On 1/1/24 11:38, Alan Condit wrote:
Hi Gene,
I had already tested my Router (also a Hitachi mv12) in a different
circuit and knew it was working. The SSR that went bye-bye was one that
I bought several years ago (used on EBay). So, after your reply, I
checked the signal from the 7i76e to the SSR and (thank goodness) it was
good. So I just went ahead and replaced the SSR with a new one. Now
everything is working.
This SSR is just controlling a line outlet. I had been using the old one
for sometime without any problems. I have never tripped a breaker. The
line into the cabinet feeds an SE600-48v switcher, a small 5v supply, a
small 24v supply and the SSR controlled line outlet.
Thanks,
Alan
*From: *gene heskett <ghesk...@shentel.net>
*Subject: **Re: [Emc-users] Damaged an SSR*
*Date: *December 31, 2023 at 1:42:07 PM CST
*To: *emc-users@lists.sourceforge.net
On 12/31/23 12:50, condit.alan--- via Emc-users wrote:
I was using an SSR to turn on the spindle on my PCBMill. By mistake I
reached over and turned off the switch on the router while it was
turned on. When I tried to turn it back on, it no longer worked. I am
hoping that I just blew out the SSR and not the 7i76e. I have a spare
SSR. Is there any precaution I should take for the future?
The only scenario I can imagine is only valid if the router has a soft
start circuit like a hitachi mv12 has. Turning it back on before it
got stopped might damage that circuit in the router. Does it work
from its own switch if plugged straight into the line?
I use big HoymC or Crydom SSR's all over the place but I also trigger
them on-off in sequence from timers in my .hal files. Usually in an
attempt to start motor supplies which if just slammed with a
mechanical switch, will instantly clear a 30 amp breaker from the turn
on in-rush, so when I do an on, they get power for the first 4 seconds
thru a 50 ohm 200 watt resistor that a second SSR shorts out 4 seconds
later after the filters are pretty well charged. With the motor itself
limited to about 2x nameplate FLA, I can run my cnc'd G0704 on a legal
for 10 gauge wire, 20 amp breaker. At turn off I throw the big
resistor back in series for a second then drop the other SSR to turn
it all off. Been doing that w/o any SSR failures I caused for about a
decade. Had a nearby lightning strike blow one of then to the
permanently on state, the only failure I've had.
Does it still work if plugged in direct? And if the SSR is switching
a duplex does a test lamp work plugged in beside the router?
Alan
Chuckle. I went a little overboard when I was making a supply for the
spindle motor on a G0704, which is a dressed up treadmill motor rated at
1hp at 90 volts and 9.7 amps grizzly was abusing with a cheap SCR based
controller. So I raided one of my ex employees for some of his
unfinished projects and came away with some big toroid transformers and
a grocery sack of 6500 uf 65 volt caps, basically making a stacked pair
of 63 volt supplies using about 16 of the caps for about 124 volts to
run the motor with, a good solid src to feed one of the PICO pwm-servo
drivers with. switching all that on along with the inrush of a couple
big stepper supplies all at once, crowbars a 30 amp breaker in the
service box that feeds just that 4 plex. So I had to stage the turn-on
by switching the power with a 60 amp SSR feeding a 50 ohm 200 watt
resistor in series with the line, charging all those caps a bit more
gently, then 4 seconds later, its safe to turn on another SSR that
shorts the 50 ohm. I now do the same thing with a 70 ohm 50 watt
resistor to soften the switchers inrush. The pwm-servo current limits at
around 18 amps if the motor gets hung, and a NEC legal 20 amp breaker in
that slot of the service stays up. The whole thing works so silently and
well that my only clue the motor is about to stall, is the squeak of the
iron in the motor when that 18 amp limit kicks in. No slowdown or other
change in the sound of its running prior to that point, and I'm getting
at least 3.5 horses out of it. For close to a decade now. Why I haven't
chewed up the gears in the mill head is beyond me, the gears are nylon!
That controller is a 4 quadrant controller. And I enjoy doing tricks in
hal, one of which is the use of a mux-4, which if it doing 3000 revs I
can reach up and turn the gears shift knob, which untally's the gear its
in which brings the motor down to about 30 rpm before I can tyurn the
knob another 10 degrees, so I can switch gears while its running at full
song but while I'm turning the gear shift knob its just creeping, too
slow to hurt anything the other gear meshes perfectly without me having
to grb the spindle and turn it till the gears engage, then in the last
degree to the stop, the tally switch for that gear closes and 150
milliseconds later the spindle is turning 1500 revs in low gear.
Similar hal trickery also allows the spindle to reverse when rigid
tapping in under 400 milliseconds. There is about 100 milliseconds when
that 4 quadrant controller runs that 130 volt worth of caps up to around
170 volts, but then it uses that over-voltage to accelerate in the other
direction, a surge that never gets to that 4 plex, its all from the caps
so the shop lights don't blink, ever. My theory is that the momentary
over voltage does cause some leakage in the caps, but is gone again
before any heat is generated, basically keeping those caps fully
"formed" And they've been abused like that for right at a decade.
VFD's are also 4 quad controllers and it recommended by the vfd makers
that the big storage caps be replaced at 5 year intervals but I'm doing
essentially the same thing with that Sheldon with its 40 lb 4 jaw chuck
as it have rigged to do rigid tapping, so the reversal time, with
careful tuning of the vfd, can reverse that 40 lb chuck turning at 100
revs, in about 500 milliseconds, with a total over travel of 1/4 turn
getting stopped. One of the things I actually meter in my lathes axis
display. At 500 revs, it is 5 or 6 turns of coarse. And again the shop
lights don't even think about blinking, its all between the motor and
the vfd with a bit of hal trickery thrown in.
Take care, stay warm nd well, Alan.
Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
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