Re: [Emc-users] VFD Tweaking

2016-03-29 Thread Nicklas Karlsson 
> ...
> So, I reset the VFD to factory settings, and tried running from the
> operator panel. Lo and behold it all worked fine, and at 100Hz I get
> the full 3000rpm spindle speed that the lathe is rated for.
> Oddly, the display at 50Hz / 1440 rpm _still_ only says 3.5A.

There is a very strong correlation between current and load/torque.

> ...

>  I am also very baffled why the same motor would trip out a 3hp VFD at
> 12A and 1500 rpm but run at 3000 rpm at 3.5A with a 4hp VFD.

Probably because of wrong parameters. Flux weakening by lowering voltage is 
possible, to move in the opposite direction by applying full voltage at lower 
than rated speed is possible but is probably not a very good idea.


Nicklas Karlsson

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Re: [Emc-users] VFD Tweaking

2016-03-29 Thread andy pugh 
On 7 January 2016 at 23:20, John Kasunich  wrote:
>> I am sure you are right, but that wasn't my point. 240V single-phase
>> VFDs largely top-out at 3HP.
>
> Doesn't need to be single phase input.
>
> A single-phase input VFD has modestly up-rated diodes and caps to
> handle the higher peak currents and ripple current that comes with
> a single phase operation.


Clearly there is a lot more to this VFD thing than I thought.

I got a 4hp Huangyang VFD from that eBay. Communicating with it via
RS485 turned out to be very easy with the hy_vfd HAL component.

This evening I connected it to the lathe, and found that the lathe
would turn at very low speeds, but then it was acting like the
clutches were not working.
But it had all worked OK before, and nothing had changed but the VFD.

So I fitted the castor-frame to the lathe, and rolled it away from the
wall so that I could see the motor shaft.
Very bizarrely the motor was running weakly at low speed requests,
then getting even weaker at higher speed requests, and basically
stopping at a VFD-displayed 50Hz and 3.5A.

Well, at least it wasn't a clutch problem..

So, I reset the VFD to factory settings, and tried running from the
operator panel. Lo and behold it all worked fine, and at 100Hz I get
the full 3000rpm spindle speed that the lathe is rated for.
Oddly, the display at 50Hz / 1440 rpm _still_ only says 3.5A.

Setting it back to RS485 didn't bring back the wierd behaviour, it was
running happily at 3000 rpm in high range and seemed to make decent
torque down to 80rpm in low range.

So, I have no idea what was wrong at first, but maybe it got unhappy
being powered up with no motor when I was setting up RS485.

 I am also very baffled why the same motor would trip out a 3hp VFD at
12A and 1500 rpm but run at 3000 rpm at 3.5A with a 4hp VFD.

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Re: [Emc-users] VFD Tweaking

2016-01-20 Thread andy pugh 
On 15 January 2016 at 14:59, andy pugh  wrote:

> It's an interesting device, and I think I have repaired it. Pictures here:
>
> http://bodgesoc.blogspot.co.uk/2016/01/holbrook6.html

And the latest is that the Variator now seems to work:
https://www.youtube.com/watch?v=0uGYNYR-6SA

But I have made a bracket to not use it:
https://picasaweb.google.com/108164504656404380542/Holbrook#6242003069535317714

The spindle now spins to 2500 but still not the full 3000.
There is a good chance that the spindle oil pump was broken for long
enough for damage to occur to the head bearings. I have to admit that
they do rumble a bit.

I will get the lathe fully functional first, then decide on head bearings.
Bearings are listed as 387/382B Which are available and not as
frightening as I feared:
http://simplybearings.co.uk/shop/p40679/Major-Brand-387/382B-Imperial-Taper-Roller-Bearing-Flanged-Cup-and-Cone-Set-2.25x3.8125x0.8268-inch/product_info.html

Though if I _really_ like the lathe, perhaps I will get carried away:
http://simplybearings.co.uk/shop/Taper-Roller-Bearings-Super-Precision-Taper-Roller-Bearings-Flanged-Cup-Type-Taper-Roller-Bearings/c1_5458_5461/p20036435/Gamet-110057X/110096XC-Super-Precision-Tapered-Roller-Bearing-Flanged-Cup-Type-57.15x96.838x29.5mm/product_info.html

I don't know how much those are, but 55/100mm ones are £216 each.

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Re: [Emc-users] VFD Tweaking

2016-01-20 Thread John Kasunich 


On Wed, Jan 20, 2016, at 06:17 PM, andy pugh wrote:
> On 15 January 2016 at 14:59, andy pugh  wrote:
> 
> > It's an interesting device, and I think I have repaired it. Pictures here:
> >
> > http://bodgesoc.blogspot.co.uk/2016/01/holbrook6.html
> 
> And the latest is that the Variator now seems to work:
> https://www.youtube.com/watch?v=0uGYNYR-6SA
> 
> But I have made a bracket to not use it:
> https://picasaweb.google.com/108164504656404380542/Holbrook#6242003069535317714
> 

If it works, and you expect it to continue to work, why not use it?
You will have more HP delivered to the spindle over the full speed range
than if you were to use only the VFD and 2-speed box.

That control shaft turns easily - looks like a NEMA 23 stepper would have
no trouble controlling it.

Although I guess sequencing is a challenge, can only adjust while running.
Are there clutches downstream of the variator?  I'd be tempted to rig a crude
low PPR encoder on the output shaft of the variator, start the motor with 
clutches off, adjust variator to desired gearbox input speed, then close either 
the high or low range clutch to start the spindle.

Although I guess you would rather have the gentle acceleration (and
dynamic braking) that comes from starting and stopping with the VFD
instead of the clutches.

OK, I'm starting to understand your decision :-)


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Re: [Emc-users] VFD Tweaking

2016-01-20 Thread andy pugh 
On 20 January 2016 at 23:49, John Kasunich  wrote:
> That control shaft turns easily - looks like a NEMA 23 stepper would have
> no trouble controlling it.
>
> Although I guess sequencing is a challenge, can only adjust while running.
> Are there clutches downstream of the variator?  I'd be tempted to rig a crude
> low PPR encoder on the output shaft of the variator, start the motor with
> clutches off, adjust variator to desired gearbox input speed, then close 
> either
> the high or low range clutch to start the spindle.

I have considered that sort of thing, and I have it in reserve if I
don't like VFD-only control.
It isn't a huge job to put the Variator back in again.

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Re: [Emc-users] VFD Tweaking

2016-01-20 Thread Jon Elson 
On 01/20/2016 05:17 PM, andy pugh wrote:
> I will get the lathe fully functional first, then decide 
> on head bearings. Bearings are listed as 387/382B Which 
> are available and not as frightening as I feared: 
> http://simplybearings.co.uk/shop/p40679/Major-Brand-387/382B-Imperial-Taper-Roller-Bearing-Flanged-Cup-and-Cone-Set-2.25x3.8125x0.8268-inch/product_info.html

Wow, really lucky they are that cheap on a big lathe.  I 
fear a set for my 15" Sheldon would run about what I paid 
for the lathe - $2300 or so.

Jon

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Re: [Emc-users] VFD Tweaking

2016-01-15 Thread andy pugh 
To add to this thread. It became more and more likely that the
Variator was the source of the trouble, and then abundantly clear when
the Variator locked up.

It's an interesting device, and I think I have repaired it. Pictures here:

http://bodgesoc.blogspot.co.uk/2016/01/holbrook6.html

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Re: [Emc-users] VFD Tweaking

2016-01-15 Thread Jim Craig 
On 1/15/2016 8:59 AM, andy pugh wrote:
> To add to this thread. It became more and more likely that the
> Variator was the source of the trouble, and then abundantly clear when
> the Variator locked up.
>
> It's an interesting device, and I think I have repaired it. Pictures here:
>
> http://bodgesoc.blogspot.co.uk/2016/01/holbrook6.html
>
That is an interesting device. I have not seen anything like that 
before. It was also an entertaining read.

Thanks for the link.

Jim

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Re: [Emc-users] VFD Tweaking

2016-01-08 Thread John Kasunich 


On Thu, Jan 7, 2016, at 08:29 PM, Steve Traugott wrote:
> On Thu, Jan 7, 2016 at 5:14 PM, Brian Morel  wrote:
> 
> > As far as the current issue, you need to be careful using old motors with
> > a vfd.  The insulation ratings of the older motors were not designed to
> > handle the voltage spikes that can occur with running motors fairly
> > deviated from their original hz designs.
> >
> 
> This sounds to me like a likely culprit.  The high-frequency, high-amperage
> switching on the output side of a VFD causes high voltage transients which,
> if the motor isn't rated for VFD duty, can pierce the winding insulation
> and cause internal arcing and carbon tracks.  You may be seeing higher
> current simply because the windings are now shorting together in a few
> spots.
> 
> I remember spending some time searching for a good 5 HP motor with the
> right insulation rating to run on a VFD -- they cost a bit more, and are
> harder to find.  I don't now remember what the magic designation is, but a
> quick google search just now tells me it may have been "class H"
> insulation.  In several subsequent years of running said motor and VFD,
> I've never had any issues.
> 
> This looks like a pretty good overview:
> http://energy.gov/sites/prod/files/2014/04/f15/motor_tip_sheet14.pdf
> 
> Steve

If you are doing 400V (EU) or 480V (USA), this is definitely an issue to
think about when retrofitting a VFD to an older motor.  But many LinuxCNC
retrofits are on smaller machines with 240V motors.  Including Andy's
machine that started this thread.  On a 240V motor the insulation system
is usually a non-issue, unless the motor is really ancient.

>From the paper that Steve referenced above:

 The insulation system on a 208/230-V motor is identical to that
 of a 460-V motor. Thus, voltage spikes produced by inverters on
 208- or 230-V systems are unlikely to cause insulation damage
 at any cable length or drive carrier frequency.


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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Jon Elson 
On 01/07/2016 05:14 PM, Stephen Dubovsky wrote:
> FWIW, I have a 7hp hitachi vfd on my Sheldon R15 (5hp motor.) running from
> 1ph 240V.  I found the drive cheap so I simply oversized it vs building an
> external rectifier/cap.
>
>
HAH!  I can top that!  I have an 11 KW Tosvert VFD on MY 
Sheldon R15.   No need to worry about the rectifier/caps on 
that.

Jon

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread John Kasunich 


On Thu, Jan 7, 2016, at 05:31 PM, andy pugh wrote:
> On 7 January 2016 at 22:10, John Kasunich  wrote:
> 
> > This is rarely ever done in industry because industry doesn't want
> > to pay for the extra iron, copper, silicon, and capacitors needed
> > to build a 10HP motor and VFD when they're only going to get
> > 2HP from the shaft.  But for a one-off where you find the motor
> > and/or VFD cheap on eBay or a scrap-heap, it can work very well.
> 
> I am sure you are right, but that wasn't my point. 240V single-phase
> VFDs largely top-out at 3HP.

Doesn't need to be single phase input.

A single-phase input VFD has modestly up-rated diodes and caps to
handle the higher peak currents and ripple current that comes with
a single phase operation.

A larger three-phase input drive running at half or less of its rating
doesn't need any up-rating, the parts are already large because the
drive is large.

You don't want a drive that will refuse to run on single phase.  But
I haven't encountered any such things until you get to 50-100HP or
more.  Smaller ones just have ordinary dumb diode bridges and 
no clue whether the input is missing a phase. 

If there is any form phase loss protection, it is likely based on looking
at the cap bank ripple voltage because that doesn't require any extra
sensors.  Again, the derate helps.  Running a 10HP drive at 10HP
on single phase will cause a lot of cap ripple voltage, and the drive
might well detect that and trip to save the caps.  Running that same
drive at 2HP on single phase is likely to have less ripple than running
at 10HP on three phase.  The detection algorithm won't have a clue.

> 
> https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/?filter=Input%7c230Vac+1ph
> Does actually list some, I admit. But I am fairly sure that there
> weren't any over 2.2kW last time I looked a couple of years ago.
> 
> -- 
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> If you can't fix it, you don't own it.
> http://www.ifixit.com/Manifesto
> 
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 23:20, John Kasunich  wrote:

>> I am sure you are right, but that wasn't my point. 240V single-phase
>> VFDs largely top-out at 3HP.
>
> Doesn't need to be single phase input.

Interesting.

However, it is starting to look likely that the VFD I have will be OK
if I remove the Variator.
I might even have a buyer for the Variator, there is a chap in
Australia who want's to buy all the parts that I take off the lathe,
and as he has no drivetrain at all, I suspect he might be interested.
I will have to determine if it is actually broken first, of course.

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Stephen Dubovsky 
They do typ top out around 3HP 1ph.  So just don't use them;)

What John pointed out is entirely correct.  The inverter runs from a
rectified DC bus.  There are 2 things limiting you running a 3ph vfd on a
1ph line.
1) Phase loss detection.  Some big inverters will fault if they detect one
of the phase inputs missing - it can usually be disabled in a software
setting though.
2) heating and ripple in the diode rectifer and caps.  There will be more
ripple current in the caps on 1ph AND it will be going though only 4 diodes
(vs 6 in a 3ph configuration.)  They will be more stressed.  This is why
most people recommend oversizing a 3ph vfd if running it on single phase -
to get oversized caps and diodes.  But if you are using a 10hp motor to
replace a gearbox, you will never actually be drawing 10hp but only 2hp as
high torque at low speed = low hp.  (if you resist the temptation to
overload the original machine and use all the avail new hp;))  There are
however easy solutions if you actually want to run a 10hp vfd *AT* 10hp.
Every one I've ever seen has the rectified DC bus available at terminals.
You can add more external caps to that bus.  You can even use a BEEFY
external rectifier thats rated at your single phase ripple to feed the VFD
w/ DC directly (again, phase loss detection needs to be turned off.)

FWIW, I have a 7hp hitachi vfd on my Sheldon R15 (5hp motor.) running from
1ph 240V.  I found the drive cheap so I simply oversized it vs building an
external rectifier/cap.

SMD

On Thu, Jan 7, 2016 at 5:31 PM, andy pugh  wrote:

> On 7 January 2016 at 22:10, John Kasunich  wrote:
>
> > This is rarely ever done in industry because industry doesn't want
> > to pay for the extra iron, copper, silicon, and capacitors needed
> > to build a 10HP motor and VFD when they're only going to get
> > 2HP from the shaft.  But for a one-off where you find the motor
> > and/or VFD cheap on eBay or a scrap-heap, it can work very well.
>
> I am sure you are right, but that wasn't my point. 240V single-phase
> VFDs largely top-out at 3HP.
>
>
> https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/?filter=Input%7c230Vac+1ph
> Does actually list some, I admit. But I am fairly sure that there
> weren't any over 2.2kW last time I looked a couple of years ago.
>
> --
> atp
> If you can't fix it, you don't own it.
> http://www.ifixit.com/Manifesto
>
>
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 23:14, Stephen Dubovsky  wrote:
> 1) Phase loss detection.  Some big inverters will fault if they detect one
> of the phase inputs missing - it can usually be disabled in a software
> setting though.

OK, I wasn't aware that it could be switched off. With one I have
played with previously that wasn't an option.
(The current item under discussion allows it, but there is no need)

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread John Dammeyer 
I think that was my original point.  Capacitors are expensive and bulky.
Especially if you buy ones that have wide temperature ranges and can handle
a large amount of ripple current.  All which are a requirement for switching
power supplies which is what the VFD really is.

A manufacturing building a VFD for use on 3phase can use a smaller capacitor
than one who has to limit to the same ripple on single phase.  Here's a
simple explanation.
http://www.electroschematics.com/7048/capacitor-input-filter-calculation/

With 3 phase there is less time between each peak to recharge the capacitor
and therefore the ripple is lower with the same size capacitor.  Or the same
with a smaller value capacitor.   If the ripple is too much then the VFD
will probably fault out or become eratic.

My simple and inexpensive Automation Direct VFD meant for 1HP can run a 1 HP
motor on 3 phase.  My South Bend lathe originally had a 3/4HP motor and it's
unlikely I'd even load it at full RPM to require the 1 HP so I can get away
with single phase input for a 1HP motor.  The lathe headstock bearings are
the limiting factor for top speed on my lathe.

And as Stephan mentioned, the diodes can also be an issue if they are sized
on the edge and expected to work with 3 phase.

John



> -Original Message-
> From: Stephen Dubovsky [mailto:smdubov...@gmail.com]
> Sent: January-07-16 3:14 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] VFD Tweaking
> 
> 
> They do typ top out around 3HP 1ph.  So just don't use them;)
> 
> What John pointed out is entirely correct.  The inverter runs from a
> rectified DC bus.  There are 2 things limiting you running a 3ph vfd on a
> 1ph line.
> 1) Phase loss detection.  Some big inverters will fault if they detect one
> of the phase inputs missing - it can usually be disabled in a software
> setting though.
> 2) heating and ripple in the diode rectifer and caps.  There will be more
> ripple current in the caps on 1ph AND it will be going though only 4
diodes
> (vs 6 in a 3ph configuration.)  They will be more stressed.  This is why
> most people recommend oversizing a 3ph vfd if running it on single phase -
> to get oversized caps and diodes.  But if you are using a 10hp motor to
> replace a gearbox, you will never actually be drawing 10hp but only 2hp as
> high torque at low speed = low hp.  (if you resist the temptation to
> overload the original machine and use all the avail new hp;))  There are
> however easy solutions if you actually want to run a 10hp vfd *AT* 10hp.
> Every one I've ever seen has the rectified DC bus available at terminals.
> You can add more external caps to that bus.  You can even use a BEEFY
> external rectifier thats rated at your single phase ripple to feed the VFD
> w/ DC directly (again, phase loss detection needs to be turned off.)
> 
> FWIW, I have a 7hp hitachi vfd on my Sheldon R15 (5hp motor.) running from
> 1ph 240V.  I found the drive cheap so I simply oversized it vs building an
> external rectifier/cap.
> 
> SMD
> 
> On Thu, Jan 7, 2016 at 5:31 PM, andy pugh <bodge...@gmail.com> wrote:
> 
> > On 7 January 2016 at 22:10, John Kasunich <jmkasun...@fastmail.fm>
> wrote:
> >
> > > This is rarely ever done in industry because industry doesn't want
> > > to pay for the extra iron, copper, silicon, and capacitors needed
> > > to build a 10HP motor and VFD when they're only going to get
> > > 2HP from the shaft.  But for a one-off where you find the motor
> > > and/or VFD cheap on eBay or a scrap-heap, it can work very well.
> >
> > I am sure you are right, but that wasn't my point. 240V single-phase
> > VFDs largely top-out at 3HP.
> >
> >
> > https://www.inverterdrive.com/group/AC-Inverter-Drives-
> 230V/?filter=Input%7c230Vac+1ph
> > Does actually list some, I admit. But I am fairly sure that there
> > weren't any over 2.2kW last time I looked a couple of years ago.
> >
> > --
> > atp
> > If you can't fix it, you don't own it.
> > http://www.ifixit.com/Manifesto
> >
> >
> >

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Brian Morel 
It is very common in the industry now to run 3ph vfd's off single phase.  I've 
sold a 100hp 240v drive that runs a pump driven by a 50hp motor.  Some 
manufacturers even recommend the 2:1 ratio of vfd rating to motor rating and 
warranty the drive when it's used that way.  The real issue is the 240v 1ph 
power line size requirements.

As far as the current issue, you need to be careful using old motors with a 
vfd.  The insulation ratings of the older motors were not designed to handle 
the voltage spikes that can occur with running motors fairly deviated from 
their original hz designs.

If it was my equipment I would see if I can find out where the issue is using 
one of those contactless thermometers.  If your amperage is spiking, there is 
an induced load somewhere, and you might be able to figure out where by 
checking the temp of the motor and variator.  No idea if it would really work 
though.



Sent from my iPad

> On Jan 7, 2016, at 6:38 PM, John Dammeyer <jo...@autoartisans.com> wrote:
> 
> I think that was my original point.  Capacitors are expensive and bulky.
> Especially if you buy ones that have wide temperature ranges and can handle
> a large amount of ripple current.  All which are a requirement for switching
> power supplies which is what the VFD really is.
> 
> A manufacturing building a VFD for use on 3phase can use a smaller capacitor
> than one who has to limit to the same ripple on single phase.  Here's a
> simple explanation.
> http://www.electroschematics.com/7048/capacitor-input-filter-calculation/
> 
> With 3 phase there is less time between each peak to recharge the capacitor
> and therefore the ripple is lower with the same size capacitor.  Or the same
> with a smaller value capacitor.   If the ripple is too much then the VFD
> will probably fault out or become eratic.
> 
> My simple and inexpensive Automation Direct VFD meant for 1HP can run a 1 HP
> motor on 3 phase.  My South Bend lathe originally had a 3/4HP motor and it's
> unlikely I'd even load it at full RPM to require the 1 HP so I can get away
> with single phase input for a 1HP motor.  The lathe headstock bearings are
> the limiting factor for top speed on my lathe.
> 
> And as Stephan mentioned, the diodes can also be an issue if they are sized
> on the edge and expected to work with 3 phase.
> 
> John
> 
> 
> 
>> -Original Message-
>> From: Stephen Dubovsky [mailto:smdubov...@gmail.com]
>> Sent: January-07-16 3:14 PM
>> To: Enhanced Machine Controller (EMC)
>> Subject: Re: [Emc-users] VFD Tweaking
>> 
>> 
>> They do typ top out around 3HP 1ph.  So just don't use them;)
>> 
>> What John pointed out is entirely correct.  The inverter runs from a
>> rectified DC bus.  There are 2 things limiting you running a 3ph vfd on a
>> 1ph line.
>> 1) Phase loss detection.  Some big inverters will fault if they detect one
>> of the phase inputs missing - it can usually be disabled in a software
>> setting though.
>> 2) heating and ripple in the diode rectifer and caps.  There will be more
>> ripple current in the caps on 1ph AND it will be going though only 4
> diodes
>> (vs 6 in a 3ph configuration.)  They will be more stressed.  This is why
>> most people recommend oversizing a 3ph vfd if running it on single phase -
>> to get oversized caps and diodes.  But if you are using a 10hp motor to
>> replace a gearbox, you will never actually be drawing 10hp but only 2hp as
>> high torque at low speed = low hp.  (if you resist the temptation to
>> overload the original machine and use all the avail new hp;))  There are
>> however easy solutions if you actually want to run a 10hp vfd *AT* 10hp.
>> Every one I've ever seen has the rectified DC bus available at terminals.
>> You can add more external caps to that bus.  You can even use a BEEFY
>> external rectifier thats rated at your single phase ripple to feed the VFD
>> w/ DC directly (again, phase loss detection needs to be turned off.)
>> 
>> FWIW, I have a 7hp hitachi vfd on my Sheldon R15 (5hp motor.) running from
>> 1ph 240V.  I found the drive cheap so I simply oversized it vs building an
>> external rectifier/cap.
>> 
>> SMD
>> 
>>> On Thu, Jan 7, 2016 at 5:31 PM, andy pugh <bodge...@gmail.com> wrote:
>>> 
>>>> On 7 January 2016 at 22:10, John Kasunich <jmkasun...@fastmail.fm>
>>> wrote:
>>> 
>>>> This is rarely ever done in industry because industry doesn't want
>>>> to pay for the extra iron, copper, silicon, and capacitors needed
>>>> to build a 10HP motor and VFD when they're only going to get
>>>> 2HP from the shaft.  But for a one-off where you

[Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
My lathe has a 3HP motor driven by a 3hp VFD.
There is also a Kopp Variator variable speed drive, and a 2-speed
gearbox with electromagnetic clutches.

Running at 50Hz it thus has two speeds, 10-500rpm and 80-3000 rpm.

The VFD works fine in the lower range, but in the higher speed range,
unless the variator is wound down to a low speed, the VFD current
reaches 18A and the VFD trips out.

I am wondering if the 1968 3hp motor was made of bigger horses than
the 2015 3hp VFD.

I further wonder if I can change the V/F curve to keep the motor
current inside the limits of the VFD. Does that seem reasonable, or
will the motor simply run slower, make less back-emf and sink even
more current?

This might be a link to the manual
http://www.lovatoelectric.com/HandlerDoc.ashx?s=I365GB12_12.pdf=119

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread alex chiosso 
Hi Andy.
Did you fit the proper values for the paramters Group 1 and 2 ?
This VFD seem to have no selftuning procedure isn't it ?
In any case I do believe that the VFD is maybe too small for the motor
you're running (old type).
Have you tried to measure the motor current value drived without the VFD ?
In the VFD parameters you can setup the maximum current on the motor and
the VFD should protect itself from an overload (or it should do).

Regards

On Thu, Jan 7, 2016 at 3:32 PM, Dave Caroline 
wrote:

> My old Adcock and Shipley mill motor has some of those larger horses,
> two dead VFDs so far.
>
> Dave Caroline
>
> On 07/01/2016, andy pugh  wrote:
> > My lathe has a 3HP motor driven by a 3hp VFD.
> > There is also a Kopp Variator variable speed drive, and a 2-speed
> > gearbox with electromagnetic clutches.
> >
> > Running at 50Hz it thus has two speeds, 10-500rpm and 80-3000 rpm.
> >
> > The VFD works fine in the lower range, but in the higher speed range,
> > unless the variator is wound down to a low speed, the VFD current
> > reaches 18A and the VFD trips out.
> >
> > I am wondering if the 1968 3hp motor was made of bigger horses than
> > the 2015 3hp VFD.
> >
> > I further wonder if I can change the V/F curve to keep the motor
> > current inside the limits of the VFD. Does that seem reasonable, or
> > will the motor simply run slower, make less back-emf and sink even
> > more current?
> >
> > This might be a link to the manual
> > http://www.lovatoelectric.com/HandlerDoc.ashx?s=I365GB12_12.pdf=119
> >
> > --
> > atp
> > If you can't fix it, you don't own it.
> > http://www.ifixit.com/Manifesto
> >
> >
> --
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>
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Steve Traugott 
Here's a better VFD/motor matching overview, with a pretty picture of
what's going on (scroll down until you get to the schematic showing the
three output PWM waves):

http://www.franklin-controls.com/pump/blog/motors/

On Thu, Jan 7, 2016 at 5:29 PM, Steve Traugott  wrote:

> On Thu, Jan 7, 2016 at 5:14 PM, Brian Morel 
> wrote:
>
>> As far as the current issue, you need to be careful using old motors with
>> a vfd.  The insulation ratings of the older motors were not designed to
>> handle the voltage spikes that can occur with running motors fairly
>> deviated from their original hz designs.
>>
>
> This sounds to me like a likely culprit.  The high-frequency,
> high-amperage switching on the output side of a VFD causes high voltage
> transients which, if the motor isn't rated for VFD duty, can pierce the
> winding insulation and cause internal arcing and carbon tracks.  You may be
> seeing higher current simply because the windings are now shorting together
> in a few spots.
>
> I remember spending some time searching for a good 5 HP motor with the
> right insulation rating to run on a VFD -- they cost a bit more, and are
> harder to find.  I don't now remember what the magic designation is, but a
> quick google search just now tells me it may have been "class H"
> insulation.  In several subsequent years of running said motor and VFD,
> I've never had any issues.
>
> This looks like a pretty good overview:
> http://energy.gov/sites/prod/files/2014/04/f15/motor_tip_sheet14.pdf
>
> Steve
>
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Jim Craig 
Excellent information John! I learned something today.

I may have to go with a larger motor and VFD for my mill if I decide to 
remove the variable sheave belt drive.


On 1/7/2016 4:10 PM, John Kasunich wrote:
> Actually, the domestic (input) power is not an issue.  The only factor is
> the cost of the oversized motor and VFD.  Anyone lucky enough to
> find a really good deal on a motor/VFD rated significantly more than
> the nominal HP of their machine can take advantage of it to get more
> torque at low speeds.
>
> Think about what a VFD does:
>
> The rectifier section of the VFD converts fixed frequency and voltage
> input power into fixed voltage DC power and stores it in a capacitor bank.
>
> The inverter section of the VFD converts fixed voltage DC power from
> the capacitor bank into variable voltage variable frequency AC power
> and sends it to the motor.
>
> The power delivered to the motor contains two components - real and
> reactive power.  The real power is converted to mechanical power at
> the shaft.  The reactive power provides the magnetic fields needed to
> make the motor work.  The reactive power sloshes back and forth
> between the motor phases and the power line (if across-the-line) or
> between motor phases and the cap bank (if VFD), with no net power
> transfer.
>
> Lets say the original motor on the machine was 2HP, three phase.
> Connected across-the-line on a big industrial 3-phase line, and loaded
> to 2HP, it might draw 6A - this reflects both real and reactive power.
> Uncouple the shaft, and the no load current reflects only the reactive
> power.  Typically 30-50% of full load current - let's say it is 40% for this
> motor, so 2.4A.  So the reactive power required or this motor is
> 2.4A*240V*sqrt(3) = 1kVA.  This is constant, regardless of the load
> on the shaft.
>
> Put the 10HP motor across that same big industrial line, and load it
> down to 10HP.  The full load phase current might be 30A.  No-load
> current might be 40% of that, or 12A.  The reactive power requirement
> is 12*240*sqrt(3) = 5kVA.  Again, it is constant regardless of load.
>
> If you had a three phase 6A power line capable of running the 2HP
> motor without a VFD at full load, it couldn't even run the 10HP motor
> at NO load, because it couldn't supply the 12A of reactive power.
>
> But with the VFD things change.  Since the inverter provides all the
> reactive power, the line never sees it.  The line and the rectifier section
> only have to handle the real power.  So the 10HP VFD can spin up
> the unloaded 10HP motor, while drawing next to no power from the
> 2HP power line.
>
> If you are running at rated speed (say 1500 RPM) and start to apply
> load torque, the line will have to supply the real power.  When the
> torque reaches 7 ft-lbs, the shaft power will be 2HP.  At that point
> you need to stop increasing the torque, or you will overload the line.
>
> But the motor and drive were both designed to deliver 10HP.  That
> means the motor COULD deliver 35 ft-lbs of torque at any speed
> from zero (with adequate cooling) to 1500 RPM.
>
> If you drop the speed from 1500 RPM to 300 RPM, you can increase
> the torque from 7 ft-lbs to 35 ft-lbs and the real power is still only 2HP.
> Since the real power is 2HP, the power line can deliver it.  An ammeter
> on the single phase input line might show 8-9 amps, but the same
> ammeter on the motor connections could show 30 amps.
>
> This is rarely ever done in industry because industry doesn't want
> to pay for the extra iron, copper, silicon, and capacitors needed
> to build a 10HP motor and VFD when they're only going to get
> 2HP from the shaft.  But for a one-off where you find the motor
> and/or VFD cheap on eBay or a scrap-heap, it can work very well.
>


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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Gene Heskett 
On Thursday 07 January 2016 09:10:23 andy pugh wrote:

> My lathe has a 3HP motor driven by a 3hp VFD.
> There is also a Kopp Variator variable speed drive, and a 2-speed
> gearbox with electromagnetic clutches.
>
> Running at 50Hz it thus has two speeds, 10-500rpm and 80-3000 rpm.
>
Those ranges aren't identical, it would be 4000 rpm as a top speed 
otherwise.

> The VFD works fine in the lower range, but in the higher speed range,
> unless the variator is wound down to a low speed, the VFD current
> reaches 18A and the VFD trips out.

Acc that manual, it should be able to goto 20.5 amps (from the source 
line), not 18. On this side of the pond that would be at least a 10 
gauge circuit, possibly 8 depending on how far from the service.

> I am wondering if the 1968 3hp motor was made of bigger horses than
> the 2015 3hp VFD.

1 HP, I was always told, will raise a 550 lb weight 1 foot in 1 second. 

They do not seem to use a horsepower translation, and I don't have a clue 
how to compare a 1 hp PMDC motor that claims to use 9.5 amps at full 
song from a 127 volt AC input with that of a 3 phase motor. That 1HP, as 
shipped, made 2250 rpms in high gear at the spindle, BUT when fed from a 
127 Volt DC supply through one of Jon's pwm servo drivers, turns 2750 at 
no load. The OEM controller was an scr based unit that also restricted 
the speed in reverse to about 110 revs, but with the pwm servo driver, 
is orthogonal, spinning as fast in reverse as fwd.

But my gut reaction is that a 2.2kw inverter should translate to about 
2.5 HP.

You said electromagnetic clutches for the gear change, are these band 
brakes, or mechanical dogs or sliding gears that can only be changed at 
zero or creep speeds?  I'm thinking if band brakes, the released band is 
dragging, and half an hours running at the higher range might disclose 
heating in that gearbox.

There is always a possibility that the variator's higher speed ranges may 
have excessive friction from uneven wear. That I would think, would also 
result in additional, detectable, heat being developed in the variator.

I also assume you've already checked those.  AIUI, your normal line 
voltage for a single phase circuit is something in the 220 volt 50 Hz 
range, which could add a gauge number from what we'd use on this side of 
the pond, meaning that a 10 gauge feed line should be sufficient. We 
have more than 220 here for the full load wireing, closer to 254 these 
days but of course thats from a center tapped circuit giving 127 to 
ground for either leg. OTOH I expect you've already metered that for 
excessive losses.  You don't miss much.
>
> I further wonder if I can change the V/F curve to keep the motor
> current inside the limits of the VFD. Does that seem reasonable, or
> will the motor simply run slower, make less back-emf and sink even
> more current?

I'd think that factory defaults should be the most efficient settings.

I am thinking in terms of supply voltage stiffness issues, or excessive 
friction someplace in the drive between motor and chuck including both 
motor and headstock bearings. That, and the inverter could be a mite 
puny for 3HP.

Basically, if the HP is put in, it has to be converted to 
heat "someplace". In this case apparently not at the cutting tool edge.

> This might be a link to the manual
> http://www.lovatoelectric.com/HandlerDoc.ashx?s=I365GB12_12.pdf=119

Let us know what you find.

Cheers, Gene Heskett
-- 
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 15:01, alex chiosso  wrote:

> In the VFD parameters you can setup the maximum current on the motor and
> the VFD should protect itself from an overload (or it should do).

That doesn't seem to be how it works.

If the current goes over the specified motor current (02-01) then it
trip out on motor-overload
if the current is higher than the 18A VFD limit then it trips out on
VFD overload.

What I want to do is not trip out on either overload limit. I was
wondering what the likely effect would be of reducing the applied
voltage in an attempt to limit the current.

Fitting a bigger VFD will be difficult as I only have 240V single phase.

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Dave Caroline 
What I did was reduce the maximum acceleration so the motor took less
current coming up to speed.


Dave Caroline

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Steve Traugott 
On Thu, Jan 7, 2016 at 5:14 PM, Brian Morel  wrote:

> As far as the current issue, you need to be careful using old motors with
> a vfd.  The insulation ratings of the older motors were not designed to
> handle the voltage spikes that can occur with running motors fairly
> deviated from their original hz designs.
>

This sounds to me like a likely culprit.  The high-frequency, high-amperage
switching on the output side of a VFD causes high voltage transients which,
if the motor isn't rated for VFD duty, can pierce the winding insulation
and cause internal arcing and carbon tracks.  You may be seeing higher
current simply because the windings are now shorting together in a few
spots.

I remember spending some time searching for a good 5 HP motor with the
right insulation rating to run on a VFD -- they cost a bit more, and are
harder to find.  I don't now remember what the magic designation is, but a
quick google search just now tells me it may have been "class H"
insulation.  In several subsequent years of running said motor and VFD,
I've never had any issues.

This looks like a pretty good overview:
http://energy.gov/sites/prod/files/2014/04/f15/motor_tip_sheet14.pdf

Steve
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Les Newell 
One way to avoid the arcing problem is to add some inductance to each 
phase between the VFD and motor. The inductors slow down those fast 
switching edges and protect the motor windings.
If you know what you are doing you can also add some capacitance after 
the inductors to get an almost perfect sine wave. You have to be careful 
doing this if you vary the speed because you can get resonance between 
the inductors and capacitors which will do odd things to the voltage at 
some frequencies.

A while back I scored a large 240->415 (UK mains voltages) auto 
transformer so I now have a 415 single phase main that I use to supply 
VFDs on my converted 3-phase machines.

Les

> This sounds to me like a likely culprit.  The high-frequency, high-amperage
> switching on the output side of a VFD causes high voltage transients which,
> if the motor isn't rated for VFD duty, can pierce the winding insulation
> and cause internal arcing and carbon tracks.  You may be seeing higher
> current simply because the windings are now shorting together in a few
> spots.


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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Stephen Dubovsky 
The lack of torque multiplication by removing a variator/gearbox can be
partially solved by just using a bigger motor.  Its my understanding that
Monarch use a 10hp motor+VFD for 10EE retrofits instead of using a
gearbox.  Simple.  The original MG set versions used a 3hp??  Though I have
no idea w/ all the series conversion efficiencies n that thing what you
realistically got out of the last shaft at the end.  You can get another
~2x multiplier by overspeeding an 1800rpm motor to 3600.

SMD

On Thu, Jan 7, 2016 at 3:29 PM, Stuart Stevenson  wrote:

> I don't remember exactly where (heh) but is have seen this quote somewhere
> before.
> "If you can't fix it you don't own it."
> Where might I have possibly seen that?
> On Jan 7, 2016 2:14 PM, "John Kasunich"  wrote:
>
> >
> >
> > On Thu, Jan 7, 2016, at 02:42 PM, andy pugh wrote:
> >
> > >
> > > This is strongly pointing to a mechanical problem with the Variator.
> > > Which I have been quoted £1600 to refurbish.
> > >
> > > The variator is noisy (it shouldn't be), can't be adjusted when the
> > > spindle is stopped and is difficult for a PC to control. It also might
> > > be broken.
> > >
> > > I was wondering whether to keep it, I think my mind is made up.
> >
> > Bummer.  That looked like an interesting device.  And reducing speed
> > by mechanical methods gains you torque, while reducing with a VFD
> > does not.
> >
> > If you think it's broken anyway (and not economical to send out for
> > repair), maybe it's time to get out the tools and take it apart.  Might
> > get lucky and find something that can be repaired in your own shop.
> >
> > --
> >   John Kasunich
> >   jmkasun...@fastmail.fm
> >
> >
> >
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Gene Heskett 
On Thursday 07 January 2016 11:02:06 andy pugh wrote:

> On 7 January 2016 at 15:37, John Kasunich 
> wrote:
>
> Answering the only question that I can answer immediately:
> > Second question: what is the nameplate amp rating of the motor?
> > If this is a 30A motor drawing 18A, then the motor and load is
> > probably fine and you need a VFD that can deliver 30A without
> > tripping.  If the motor nameplate says 15A, then the VFD is doing
> > its job and protecting the motor from an overcurrent that might
> > otherwise burn it up.
>
> The motor has no nameplate. However was supplied as a unit with the
> Variator (Model M18, the same as a modern M318)
> www.allspeeds.co.uk/wp-content/files_mf/brochure.pdf
>
> The manual states 5A / Phase @400V but I have rewired the motor for
> 240V.
>
> (Maybe I should try wiring it back to 440V?)
>
That might be a good idea as a test. It would cut the motor current 
nominally in half.

> If I was to use a clamp ammeter, would I look at VFD input current or
> an individual phase current? I am not 100% clear which the VFD is
> displaying.


Cheers, Gene Heskett
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Stuart Stevenson 
I don't remember exactly where (heh) but is have seen this quote somewhere
before.
"If you can't fix it you don't own it."
Where might I have possibly seen that?
On Jan 7, 2016 2:14 PM, "John Kasunich"  wrote:

>
>
> On Thu, Jan 7, 2016, at 02:42 PM, andy pugh wrote:
>
> >
> > This is strongly pointing to a mechanical problem with the Variator.
> > Which I have been quoted £1600 to refurbish.
> >
> > The variator is noisy (it shouldn't be), can't be adjusted when the
> > spindle is stopped and is difficult for a PC to control. It also might
> > be broken.
> >
> > I was wondering whether to keep it, I think my mind is made up.
>
> Bummer.  That looked like an interesting device.  And reducing speed
> by mechanical methods gains you torque, while reducing with a VFD
> does not.
>
> If you think it's broken anyway (and not economical to send out for
> repair), maybe it's time to get out the tools and take it apart.  Might
> get lucky and find something that can be repaired in your own shop.
>
> --
>   John Kasunich
>   jmkasun...@fastmail.fm
>
>
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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread John Kasunich 


On Thu, Jan 7, 2016, at 11:02 AM, andy pugh wrote:
> On 7 January 2016 at 15:37, John Kasunich  wrote:
> 
> Answering the only question that I can answer immediately:
> 
> > Second question: what is the nameplate amp rating of the motor?
> > If this is a 30A motor drawing 18A, then the motor and load is
> > probably fine and you need a VFD that can deliver 30A without
> > tripping.  If the motor nameplate says 15A, then the VFD is doing
> > its job and protecting the motor from an overcurrent that might
> > otherwise burn it up.
> 
> The motor has no nameplate. However was supplied as a unit with the Variator
> (Model M18, the same as a modern M318)
> www.allspeeds.co.uk/wp-content/files_mf/brochure.pdf

Well that is disappointing.  Did it fall off or something?  Or was there never
a nameplate?  I've never seen an industrial motor without a nameplate,
They are required by code so the installer can select the appropriate wire
size and set the overcurrent protection.

> The manual states 5A / Phase @400V but I have rewired the motor for 240V.
>
> (Maybe I should try wiring it back to 440V?)

You wrote "5A @ 400V", and then wrote "back to 440V".  Is it 400 or 440?

In the states, dual voltage motors are 460/230 (older motors might be labeled
440/220).  Either way it is a 2:1 ratio and it is done by having dual windings 
that
are connected in either series or parallel.  There are usually nine leads in the
terminal box.

My understanding is that in EU and UK, dual voltage motors are 400/230.
That is a sqrt(3):1 ratio and it is done by reconnecting from wye to delta.
There are six leads in the terminal box.

Which one applies here?  Was there a wiring diagram for the reconnection
or did you have to guess?  How confident are you that the reconnection is
correct?

If the nameplate data is truly 5A at 400V, and you converted it from wye 
to delta to run it on 230V, then the current rating should be 8.66A at 230V.

5A * 400V * sqrt(3) = 3.46kVA, and 8.66A at 230V is the same.

3HP is 2.24kW.  2.24kW / 3.46kVA = 0.65 power factor, which is maybe
a bit lower than I'm used to but not at all out of line.

There is no way you should be seeing 18A, and no reason to switch back
to 400 (or 440)V.  Doing so would hurt motor performance.  The only reason
you might want to _temporarily_ switch back is if there is uncertainty about
the connections.  Restoring it to the "as received" configuration might help
troubleshooting - although there is no guarantee that it wasn't already 
wrong.
 
> If I was to use a clamp ammeter, would I look at VFD input current or
> an individual phase current? I am not 100% clear which the VFD is
> displaying.

Look at motor current.  I would be utterly astonished if the VFD was 
displaying input current.  The vast majority don't have any form of sensor
on the input, it is the output current that matters for both motor control
and protection.

More questions:  when does the trip happen?  During acceleration,
or some time later after it has reached normal speed?  If during 
acceleration, does it happen right away (say less than 10% of 
full speed)?  Or later, at 50% speed or higher?

If it is happening during acceleration, my first guess would be that
you are trying to accelerate too fast.  It looks like your two speed
ranges have either a 6:1 (based on top speed) or 8:1 (based on 
bottom speed) ratio.  That means the spindle inertia reflected back
to the motor is either 36 or 64 times higher in high range than in
low range.

When the lathe was operated across-the-line, the motor and the
line would just grunt a little.  Current could hit 600-800% of rated,
torque might be 300-500% of nominal, and up she comes.  The 
overload relays have a time/current profile that is specifically 
designed to pass such short-term overloads, and the fuses are
also selected to deal with them.

With the VFD it is another story completely.  IGBTs don't have the
thermal mass of copper and iron, and can't handle such large 
overloads.  Most have instantaneous trip at about 200% of rating,
with an inverse time/current trip curve for lower currents.  A typical
"normal duty" drive might trip in 3 seconds at 150% and one minute
at 110%.  A "heavy duty" drive could typically give 200% for 3 seconds
and 150% for a minute.

You want to keep the current during acceleration below 150%,
by slowing down the acceleration rate.  For a load like a lathe 
where you won't be cutting during accel I'd actually aim to keep
the accel current at 100% or less - why beat things up to save
a couple seconds?

It looks like parameters 00-14 and 00-16 are acceleration times.
What do you have them set to?  If they are short, make them
longer.  The default 10 seconds should be OK, so I'm a little
perplexed - did you change the defaults?  For experimentation
purposes don't hesitate to set them to 60 seconds or so, that
will let you watch the meters as it slowly accelerates and get
a better idea of what is going on.  If a 60

Re: [Emc-users] VFD Tweaking

2016-01-07 Thread Przemek Klosowski 
On Thu, Jan 7, 2016 at 10:55 AM, Gene Heskett  wrote:
> On Thursday 07 January 2016 09:10:23 andy pugh wrote:

>> I am wondering if the 1968 3hp motor was made of bigger horses than
>> the 2015 3hp VFD.
>
> 1 HP, I was always told, will raise a 550 lb weight 1 foot in 1 second.
>
...
> But my gut reaction is that a 2.2kw inverter should translate to about
> 2.5 HP.

1HP = 0.7457 kW, right? close enough to 3/4kW for most applications.

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 18:10, John Kasunich  wrote:

>> The manual states 5A / Phase @400V but I have rewired the motor for 240V.
>>
>> (Maybe I should try wiring it back to 440V?)
>
> You wrote "5A @ 400V", and then wrote "back to 440V".  Is it 400 or 440?

It depends on where you look.
The lathe installation instructions say "440V 50Hz 3-phase"
The Variator Unit section says: "5.0 A per phase FLC at 400V"

> My understanding is that in EU and UK, dual voltage motors are 400/230.
> That is a sqrt(3):1 ratio and it is done by reconnecting from wye to delta.
> There are six leads in the terminal box.

UK power is nominally 230V to harmonise with the EU, but is 230 +10% -
5% and is normally 240V.
It was 240V when the lathe was made.
https://www.tlc-direct.co.uk/Book/1.1.htm
That also says that the spread of allowable UK 3-phase voltage is 376 to 440V.

> Which one applies here?  Was there a wiring diagram for the reconnection
> or did you have to guess?  How confident are you that the reconnection is
> correct?

There was no wiring diagram, so I guessed.
Before
https://picasaweb.google.com/108164504656404380542/Holbrook#6184070662873243538
with wires labelled A1, A2, B1, B2, C1, C2
After:
https://picasaweb.google.com/108164504656404380542/Holbrook#6184102342306740594

> 5A * 400V * sqrt(3) = 3.46kVA, and 8.66A at 230V is the same.

I left the clamp ammeter at work, but looking at the VFD display.

Low speed / low ratio: 80rpm = 3.0 A
Low speed / high ratio 500rpm = 6.0A
High speed / low ratio  500rpm = 3.4A
High speed 10 A = 2000rpm.

> More questions:  when does the trip happen?  During acceleration,
> or some time later after it has reached normal speed?  If during
> acceleration, does it happen right away (say less than 10% of
> full speed)?  Or later, at 50% speed or higher?

It rather depends on how I operate the controls.
I can start at low speed and slowly wind-up the variator and get about
1800 rpm.
However, if I want to be able to start and stop without variator
action then I have to leave the variator at the 1000 rpm setting.
As the variator can not be adjusted without the spindle turning it is
better not to have to be twiddling it before stopping to re-start.

I have, in the course of discovering the last fact, made some
interesting discoveries.

In the 1000 rpm position at 100 Hz I can have 2000 rpm at 7A.
If I stay at 50Hz and wind up the variator then the current rapidly
rises. If adjust speed to 10A then it is about 2000 rpm, but then all
of a sudden the current ramped up to 18A and the VFD tripped.

This is strongly pointing to a mechanical problem with the Variator.
Which I have been quoted £1600 to refurbish.

> It looks like parameters 00-14 and 00-16 are acceleration times.
> What do you have them set to?

They were 7.5 and 10.

>   For experimentation
> purposes don't hesitate to set them to 60 seconds or so, that
> will let you watch the meters as it slowly accelerates and get
> a better idea of what is going on.  If a 60 second accel still
> results in current of more than 8A we will need to dig deeper.

This was interesting.
In the highest gear the current ramps slowly up to 18A and a trip
without the motor even moving.
At a lower variator setting in high gear there is no motor movement
until 5A, then it starts to slowly build to 2000rpm at 7A.
Then a sudden increase to 18A and a trip.

> To be honest, for something like this I strongly believe that
> the very first step is to tell the drive everything you know about
> the motor.  The highest priority are parameters  01-00, 01-01,
> and 02-01.  Those are absolutely necessary.  You probably
> want "1", "230", and "8.66" respectively.

Currently 1, 220 and 8.0.

> If you had a nameplate it would give you 02-03.  Keep 02-02
> zero since you don't know the proper value for 02-03.  If you
> can decouple the motor from all mechanical loads you could
> run it up to 50Hz to determine 02-00,   Otherwise, set 02-00
> to about 35-40% of 02-03, and keep 02-02 zero.

I could put the 2-speed box in neutral and set the Variator to minimum
speed, but the evidence really is pointing at the variator as the main
load.

The variator is noisy (it shouldn't be), can't be adjusted when the
spindle is stopped and is difficult for a PC to control. It also might
be broken.

I was wondering whether to keep it, I think my mind is made up.

-- 
atp
If you can't fix it, you don't own it.
http://www.ifixit.com/Manifesto

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 19:42, andy pugh  wrote:
> At a lower variator setting in high gear there is no motor movement
> until 5A, then it starts to slowly build to 2000rpm at 7A.
> Then a sudden increase to 18A and a trip.

I should have been more explicit here. There was no increase in speed
or output frequency, just a sudden increase in current.

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread John Kasunich 


On Thu, Jan 7, 2016, at 03:56 PM, andy pugh wrote:
> On 7 January 2016 at 20:49, Stephen Dubovsky  wrote:
> > The lack of torque multiplication by removing a variator/gearbox can be
> > partially solved by just using a bigger motor.
> 
> Not really an option on 240V domestic power.
> 3HP is almost certainly enough, with the reduction gear for big work.
> 

Actually, the domestic (input) power is not an issue.  The only factor is
the cost of the oversized motor and VFD.  Anyone lucky enough to 
find a really good deal on a motor/VFD rated significantly more than 
the nominal HP of their machine can take advantage of it to get more
torque at low speeds.

Think about what a VFD does:

The rectifier section of the VFD converts fixed frequency and voltage
input power into fixed voltage DC power and stores it in a capacitor bank. 

The inverter section of the VFD converts fixed voltage DC power from
the capacitor bank into variable voltage variable frequency AC power
and sends it to the motor.

The power delivered to the motor contains two components - real and
reactive power.  The real power is converted to mechanical power at
the shaft.  The reactive power provides the magnetic fields needed to
make the motor work.  The reactive power sloshes back and forth
between the motor phases and the power line (if across-the-line) or
between motor phases and the cap bank (if VFD), with no net power
transfer.

Lets say the original motor on the machine was 2HP, three phase.  
Connected across-the-line on a big industrial 3-phase line, and loaded
to 2HP, it might draw 6A - this reflects both real and reactive power.  
Uncouple the shaft, and the no load current reflects only the reactive
power.  Typically 30-50% of full load current - let's say it is 40% for this
motor, so 2.4A.  So the reactive power required or this motor is 
2.4A*240V*sqrt(3) = 1kVA.  This is constant, regardless of the load
on the shaft.

Put the 10HP motor across that same big industrial line, and load it
down to 10HP.  The full load phase current might be 30A.  No-load
current might be 40% of that, or 12A.  The reactive power requirement
is 12*240*sqrt(3) = 5kVA.  Again, it is constant regardless of load.  

If you had a three phase 6A power line capable of running the 2HP
motor without a VFD at full load, it couldn't even run the 10HP motor
at NO load, because it couldn't supply the 12A of reactive power.

But with the VFD things change.  Since the inverter provides all the
reactive power, the line never sees it.  The line and the rectifier section
only have to handle the real power.  So the 10HP VFD can spin up
the unloaded 10HP motor, while drawing next to no power from the
2HP power line.

If you are running at rated speed (say 1500 RPM) and start to apply
load torque, the line will have to supply the real power.  When the 
torque reaches 7 ft-lbs, the shaft power will be 2HP.  At that point
you need to stop increasing the torque, or you will overload the line.

But the motor and drive were both designed to deliver 10HP.  That
means the motor COULD deliver 35 ft-lbs of torque at any speed 
from zero (with adequate cooling) to 1500 RPM.

If you drop the speed from 1500 RPM to 300 RPM, you can increase
the torque from 7 ft-lbs to 35 ft-lbs and the real power is still only 2HP.
Since the real power is 2HP, the power line can deliver it.  An ammeter
on the single phase input line might show 8-9 amps, but the same
ammeter on the motor connections could show 30 amps.  

This is rarely ever done in industry because industry doesn't want
to pay for the extra iron, copper, silicon, and capacitors needed
to build a 10HP motor and VFD when they're only going to get
2HP from the shaft.  But for a one-off where you find the motor
and/or VFD cheap on eBay or a scrap-heap, it can work very well.

-- 
  John Kasunich
  jmkasun...@fastmail.fm

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 20:49, Stephen Dubovsky  wrote:
> The lack of torque multiplication by removing a variator/gearbox can be
> partially solved by just using a bigger motor.

Not really an option on 240V domestic power.
3HP is almost certainly enough, with the reduction gear for big work.

The Variator is 3000 rpm max output, so running a 1440 motor for the
mid range at 100Hz for the high-speed stuff ought to be a reasonable
compromise.

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 20:29, Stuart Stevenson  wrote:
> I don't remember exactly where (heh) but is have seen this quote somewhere
> before.
> "If you can't fix it you don't own it."
> Where might I have possibly seen that?

I will certainly be having a look, but I am not sure I care to invest
in the effort taken to "own" a variator.

Lots of carefully machined and matched surfaces to grind in there.

Even the special oil is £45 + £25 carriage for the Variator.

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http://www.ifixit.com/Manifesto

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Re: [Emc-users] VFD Tweaking

2016-01-07 Thread andy pugh 
On 7 January 2016 at 22:10, John Kasunich  wrote:

> This is rarely ever done in industry because industry doesn't want
> to pay for the extra iron, copper, silicon, and capacitors needed
> to build a 10HP motor and VFD when they're only going to get
> 2HP from the shaft.  But for a one-off where you find the motor
> and/or VFD cheap on eBay or a scrap-heap, it can work very well.

I am sure you are right, but that wasn't my point. 240V single-phase
VFDs largely top-out at 3HP.

https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/?filter=Input%7c230Vac+1ph
Does actually list some, I admit. But I am fairly sure that there
weren't any over 2.2kW last time I looked a couple of years ago.

-- 
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If you can't fix it, you don't own it.
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