decrease decel to stop drive from faulting wtf?

ganutenator · Oct 25, 2016

schneider drive on a dryer motor application.
15hp
They had the motor rewound/dipped/repaired or what not.
Two identical motors and vfd's.
Had customer switch the wiring.
problem followed the motor.
schneider drives group had us change the decel from 30 sec to 15 sec and the problem went away, but the tech couldn't tell us why.

I can get more info tomorrow at work. think it was 212.

dalcoleman · Oct 25, 2016

what was the fault?

wknoxfarms · Oct 26, 2016

I have run into this a few times. On a drive that controls a motor with a large flywheel weight such as pumps or fans the spin down time is fairly significant, and startup current is fairly high.

If you have rampdown time set too low it will turn the vfd off too soon and usually get back fed voltage from the still spinning motor causing a fault.

If your rampdown time is too long turning the motor slow and slower will cause current to creep up to keep running the motor. My guess would be you saw an overcurrent fault.

That's at least what i have experienced, especially in rebuilt motors. They claim they are good as new but I've never had good luck with rebuilds.

Will

ganutenator · Oct 26, 2016

E- 20 Excessive Torque Boost fault on an Altivar 212. Doesn't make sense to me because the fault was on deceleration.

wknoxfarms · Oct 26, 2016

http://www.schneider-electric.us/en/faqs/FA130598/

This explains the exact situation you described.

wknoxfarms · Oct 26, 2016

From what i gather the drive, based on values you input (voltage, hp, pf, etc..) calculates the expected torque of the motor. If that is exceeded due to incorrect setup it will cause this. Did you check to verify these setting are correct?

jraef · Oct 26, 2016

When the motor was rebuilt, did anyone re-do the "Auto-tune" procedure for the Vector Control? That's what is sounds like. The drive was tuned to the motor, then the motor was changed, the drive needed to be re-tuned because the motor equivalent circuit is no longer the same. Changing the decel time may have solved the symptom, but not the problem.

Phil Buchanan · Oct 26, 2016

jraef said:
when the motor was rebuilt, did anyone re-do the "auto-tune" procedure for the vector control? That's what is sounds like. The drive was tuned to the motor, then the motor was changed, the drive needed to be re-tuned because the motor equivalent circuit is no longer the same. Changing the decel time may have solved the symptom, but not the problem.

+1

ganutenator · Oct 26, 2016

how did you find that link, wbnox?
I wonder if there is write ups on other faults that exceed the info in the manual

ganutenator · Oct 26, 2016

I agree that lowering the decel fixed the symptoms.
yes on auto tune.
I'm going w/ bad rewind.

rootboy · Oct 26, 2016

ganutenator said:
I'm going w/ bad rewind.

That's been my experience. Not a fan of motor rebuilds.

rdrast · Oct 27, 2016

rootboy said:
That's been my experience. Not a fan of motor rebuilds.

Depends on the shop.
We've never had a problem on rewinds, even for VFD's, with the shop we use.

rootboy · Oct 27, 2016

rdrast said:
Depends on the shop.
We've never had a problem on rewinds, even for VFD's, with the shop we use.

Must be nice.

I won't bring up the name of the shop, but what they seemed best at was painting the old motor blue. Other things like tagging the leads of the motor, replacing bearings, and just generally making sure that it worked, not so much.

We got a rebuilt VFD from them once, and it still had "AFU" (which sorta stands for "All Fouled Up", but not exactly) scrawled across it in magic marker from the previous owner. I'm pretty sure that it didn't work.

The company that we used to repair electronics was no better. More than once I would take the bad parts home and repair them there.

And since both companies were "partners" with the corporation, we had no say in the matter.

decrease decel to stop drive from faulting wtf?

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