On 25 March 2014 04:08, Leonardo Marsaglia
leonardomarsagli...@gmail.com wrote:
Anyway, I think that may be using a timing pulley the ripple could be
reduced. It appears only when the axis is going up and between 3000 mm/min
and 8000 mm/min because of the high torque demand. Going down it's
Is the drive train self locking, so that if you loose power, the load
does not drop?
Or do you have a brake on the motor or someplace else?
One thing I have heard that can be a problem when using a squirrel cage
AC motor like this at very low speeds, is that the motor can overheat
due to
Field oriented control can be considered just another name for vector
control in this context. There is a distinction in that a vector
*controller* is the name given to the functions which convert the 3-phase
motor into a 2-phase reference frame upon the rotor. FOC is the whole thing
- i.e. using
2014-03-25 7:14 GMT-03:00 andy pugh bodge...@gmail.com:
You might find that if you add some bias to the PID controller then
you can make the behaviour more symmetrical. Hopefully symetrically
good, not symetrically bad. (you should find you need less P to get it
to move up)
Hi Andy,
I will
2014-03-25 12:24 GMT-03:00 Dave Cole linuxcncro...@gmail.com:
Is the drive train self locking, so that if you loose power, the load
does not drop?
Or do you have a brake on the motor or someplace else?
The joint is moved by means of a lead screw of 50 mm of diameter and 8 mm
of pitch. The
That is a good price for a drive that can do that.
Sounds like the motor will last a very long time if you run it as you
describe.
Dave
On 3/25/2014 6:09 PM, Leonardo Marsaglia wrote:
2014-03-25 12:24 GMT-03:00 Dave Cole linuxcncro...@gmail.com:
Is the drive train self locking, so that if
Yes, I hope so!
The motor was pulled out from an old beast hydro copying lathe from the
brand George Fischer. The lathe had 3 hydraulic pumps driven each one by a
5 hp electric motor.
Since the positioning system of the heater was running 3 motors (one AC
motor for the rapid feed to home
Taking back to life this topic.
I just uploaded a crappy video (sorry for the quality it was filmed with a
cheap phone) that shows how the positioning system is working.
Here's the link: https://www.youtube.com/watch?v=Rv2Y9xEkwpI
I think in the not so far future I'm going to replace the 2:1
For what you are doing, that looks really good!
Nice work!
What resolution encoder do you have on the motor?
Dave
On 3/24/2014 7:51 PM, Leonardo Marsaglia wrote:
Taking back to life this topic.
I just uploaded a crappy video (sorry for the quality it was filmed with a
cheap phone) that
Thanks Dave!
If I remember correctly the encoder is 2500 PPR. It's a lot for the kind of
job as you say so I'm pretty happy about the way it behaves.
Anyway, I think that may be using a timing pulley the ripple could be
reduced. It appears only when the axis is going up and between 3000 mm/min
On 12/12/2013 3:26 PM, Leonardo Marsaglia wrote:
2013/12/11 Dave Cole linuxcncro...@gmail.com
It sounds like you are greatly simplifying the machine. An MG set
(motor generator set) is a very old technology to create DC power. That
was probably obsolete when it was installed.
Yes indeed,
On 12/12/2013 3:30 PM, Leonardo Marsaglia wrote:
Greg and Gene (this is to avoid quoting a lot of text because you were
talking about the same thing)
I saw what the common process to make pieces out of a Delrin and Acetal is
to mold them with heat. I'm not familiar with this kind of material
On 12/12/2013 5:48 PM, Leonardo Marsaglia wrote:
2013/12/12 Gene Heskett ghesk...@wdtv.com
I expect you can, but the heat method, where the screw is clean has a
coat of mineral oil on it prevent the acetal/delrin from sticking to a dry
surface, gives you a thread that is about 40x more
On Friday 13 December 2013 09:07:06 Gregg Eshelman did opine:
On 12/12/2013 3:26 PM, Leonardo Marsaglia wrote:
2013/12/11 Dave Cole linuxcncro...@gmail.com
It sounds like you are greatly simplifying the machine. An MG set
(motor generator set) is a very old technology to create DC
On Wed, Dec 11, 2013 at 2:12 PM, Gene Heskett ghesk...@wdtv.com wrote:
On Wednesday 11 December 2013 13:50:30 Leonardo Marsaglia did opine:
It sounds like an interesting project Leonardo, so please post a link.
Question: Is this enough of a velocity variation to effect the performance
of
On 12/11/2013 4:35 PM, Leonardo Marsaglia wrote:
Yes, it would cost a lot and as you said keeping it clean requires some
kind of telescopical cover to be made. So that idea is not convenient.
I wasn't familiar with delrin, I was checking now that you mentioned and I
have some sellers near so
On Thursday 12 December 2013 08:42:15 Mark Wendt did opine:
On Wed, Dec 11, 2013 at 2:12 PM, Gene Heskett ghesk...@wdtv.com wrote:
On Wednesday 11 December 2013 13:50:30 Leonardo Marsaglia did opine:
It sounds like an interesting project Leonardo, so please post a link.
Question:
Greg and Gene (this is to avoid quoting a lot of text because you were
talking about the same thing)
I saw what the common process to make pieces out of a Delrin and Acetal is
to mold them with heat. I'm not familiar with this kind of material but
nylon 6 for example it's not complicated at all
By the way. Now the machine has a 2 to 1 reduction from the motor to the
screw and it's made with spur gears. The one on the motor and the one on
the screw are made of steel but they are related using a middle gear made
out of plastic (it's white I don't know it it's delrin or nylon, buy it has
On 12 December 2013 22:30, Leonardo Marsaglia
leonardomarsagli...@gmail.com wrote:
Are Delrin and Acetal all that different? I mean, is not
possible to thread them in the normal way?
It is perfectly possible, but the heat-moulding way gives you an exact
fit, no backlash, and no concerns that
On Thursday 12 December 2013 19:27:55 Leonardo Marsaglia did opine:
Greg and Gene (this is to avoid quoting a lot of text because you were
talking about the same thing)
I saw what the common process to make pieces out of a Delrin and Acetal
is to mold them with heat. I'm not familiar with
It's a really nice idea, I've never thought about making a thread with that
method but I think I gonna try next time I have to make a non metal thread.
2013/12/12 andy pugh bodge...@gmail.com
On 12 December 2013 22:30, Leonardo Marsaglia
leonardomarsagli...@gmail.com wrote:
Are Delrin and
2013/12/12 Gene Heskett ghesk...@wdtv.com
I expect you can, but the heat method, where the screw is clean has a
coat of mineral oil on it prevent the acetal/delrin from sticking to a dry
surface, gives you a thread that is about 40x more precise a fit _to_
_that_ _bolt_ than a tap ever
Working on my tuning I find that the vibration/oscillation I have is due to
torque. The charriot that the screw is moving is vertical and weights like
100 kg so there's a lot of force for the motor to do to lift the charriot.
That's when I get the vibrations, on the way up. On the other side, when
On 11 December 2013 12:25, Leonardo Marsaglia
leonardomarsagli...@gmail.com wrote:
I know this is due to torque but I don't know how to compensate this. If I
use low speed on the way up theres almost no vibration.
The PID component has a bias parameter which might help. I use it on
the Z of my
On Wednesday 11 December 2013 08:42:36 andy pugh did opine:
On 11 December 2013 12:25, Leonardo Marsaglia
leonardomarsagli...@gmail.com wrote:
I know this is due to torque but I don't know how to compensate this.
If I use low speed on the way up theres almost no vibration.
The PID
On 12/11/2013 06:25 AM, Leonardo Marsaglia wrote:
Working on my tuning I find that the vibration/oscillation I have is due to
torque. The charriot that the screw is moving is vertical and weights like
100 kg so there's a lot of force for the motor to do to lift the charriot.
That's when I get
On 12/11/2013 11:53 AM, Jon Elson wrote:
On 12/11/2013 06:25 AM, Leonardo Marsaglia wrote:
Working on my tuning I find that the vibration/oscillation I have is due to
torque. The charriot that the screw is moving is vertical and weights like
100 kg so there's a lot of force for the motor to do
On 12/11/2013 09:40 AM, Dave Cole wrote:
... snip
Siemens had hybrid motors that were not
standard induction motors at the time that could do better positioning
but they were as expensive ore more expensive than other companies servo
drive systems and were generally only used for very large
Well. As you say it's not the best to use an induction AC motor for a servo
work but I managed to get 0.3 or 0.4 mm of error wich is pretty cool for
the job.
I tried using the pid BIAS as Andy told to decrease vibration but nothing
happened. Also tried decreasing the servo thread speed as Gene
On Wednesday 11 December 2013 13:50:30 Leonardo Marsaglia did opine:
Well. As you say it's not the best to use an induction AC motor for a
servo work but I managed to get 0.3 or 0.4 mm of error wich is pretty
cool for the job.
I tried using the pid BIAS as Andy told to decrease vibration
If it meets your needs then you have succeeded. :-)
I have put AC servos on Induction Hardening machines before. The
machine you are using may be similar to the one I automated. The
shaft/camshaft moves vertically through an energized induction coil and
is sprayed with water to create
2013/12/11 Gene Heskett ghesk...@wdtv.com
Question: Is this enough of a velocity variation to effect the performance
of the hardening process? Or cause premature wear anyplace from the
vibration, like in the cable trough feeding this carriage?
I found the velocity variation quite good for
2013/12/11 Dave Cole linuxcncro...@gmail.com
If it meets your needs then you have succeeded. :-)
I have put AC servos on Induction Hardening machines before. The
machine you are using may be similar to the one I automated. The
shaft/camshaft moves vertically through an energized
On Wednesday 11 December 2013 17:55:39 Leonardo Marsaglia did opine:
2013/12/11 Gene Heskett ghesk...@wdtv.com
Question: Is this enough of a velocity variation to effect the
performance of the hardening process? Or cause premature wear
anyplace from the vibration, like in the cable
2013/12/11 Gene Heskett ghesk...@wdtv.com
Huge yabut there. Co$t... The precision of the ball screw apparently
isn't needed, and keeping it clean for long life could be a problem,
particularly when the nylon nut can be replaced several times during
overnight maintenance for 2% of the cost
On 12/11/2013 6:02 PM, Leonardo Marsaglia wrote:
2013/12/11 Dave Cole linuxcncro...@gmail.com
If it meets your needs then you have succeeded. :-)
I have put AC servos on Induction Hardening machines before. The
machine you are using may be similar to the one I automated. The
On Wednesday 11 December 2013 21:00:21 Leonardo Marsaglia did opine:
2013/12/11 Gene Heskett ghesk...@wdtv.com
Huge yabut there. Co$t... The precision of the ball screw apparently
isn't needed, and keeping it clean for long life could be a problem,
particularly when the nylon nut can
Well. I have some good news at leat based on my experience tuning servos. I
mounted the motor and now is working moving the screw (this is a SAE 1045
steel screw with a nut made out of nylon 6). Doing a quick tuning today I
got a 0.2 mm of error and the oscillation stoped when the joint reached
Well I tried like Andy said increasing the ferror and I can work a lot
better. Also my acceleration was too much so I decreased it and now I have
a error of 0.2 mm without fine tunning and with the motor moving air for
now, I guess that when it's attached to the screw this will be a lot
better.
On 12/05/2013 07:44 AM, Leonardo Marsaglia wrote:
Well I tried like Andy said increasing the ferror and I can work a lot
better. Also my acceleration was too much so I decreased it and now I have
a error of 0.2 mm without fine tunning and with the motor moving air for
now, I guess that when
On 12/05/2013 09:44 AM, Leonardo Marsaglia wrote:
Well I tried like Andy said increasing the ferror and I can work a lot
better. Also my acceleration was too much so I decreased it and now I have
a error of 0.2 mm without fine tunning and with the motor moving air for
now, I guess that when
2013/12/5 Kirk Wallace kwall...@wallacecompany.com
There often is a difference between the feedback resolution and the
motor resolution. For instance, if your motor can be moved to within a
degree of position, but your encoder feed back can report in tenths of a
degree. When you command a
2013/12/5 Jon Elson el...@pico-systems.com
Is this a flux vector drive, or a standard VFD? A
flux-vector drive can
perform the computations to keep the rotor excited without
moving
it. A standard VFD cannot, it has to move the motor to
excite the
induced field in the rotor. So, it will
On 12/05/2013 09:35 PM, Leonardo Marsaglia wrote:
2013/12/5 Jon Elson el...@pico-systems.com
Is this a flux vector drive, or a standard VFD? A
flux-vector drive can
perform the computations to keep the rotor excited without
moving
it. A standard VFD cannot, it has to move the motor to
I will try it with load tomorrow or next monday, because I'm finishing with
the encoder coupling for the screw. I never tried the autotunning but it is
supposed to tune all the motor parameters to get better torque. I hope that
helps to improve the positioning. Anyway as I told before I don't need
Hello all.
I managed with your help to put my 6i25 and 7i77 working.
Now I'm trying to use this to move an induction motor with a C2000 VFD to
make a positioning system. I know that this is not the best because
induction motors have no permanent magent and high inertia but Andy Pugh
made some
By the way the VFD is set to let the motor run free and I get the following
error with a max ferror of about 5 mm so It's definitely something that I'm
doing wrong.
Here's Andy's video of the spindle:
http://www.youtube.com/watch?v=3oTJNEVpvYY
Thanks!
2013/12/4 Leonardo Marsaglia
On 12/04/2013 02:19 PM, Leonardo Marsaglia wrote:
... snip
I managed to move the motor and do some tests but I can't get rid of the
oscillation from the PID. If I follow the classic way of tunning the
algorithm when I increment P I don't see any oscillation until I disturb
the motor. When that
On 4 December 2013 22:19, Leonardo Marsaglia
leonardomarsagli...@gmail.com wrote:
I managed to move the motor and do some tests but I can't get rid of the
oscillation from the PID. If I follow the classic way of tunning the
algorithm when I increment P I don't see any oscillation until I
Thanks Andy and Kirk.
I think there's nothing activated on the VFD by now, the last whing was the
acceleration.
About what you say andy, this VFD it's capable of handle a smooth turn
without load at 1 hz, but I don't know what's going to happen when the
motor is attached to the screw.
I will
51 matches
Mail list logo
