I am trying to run a 3phase 1HP motor with a running current of 4.1A on a TECO L510 VFD. I programmed the VFD for the motor rated current, but ever time I try to start, I get Overcurrent At acceleration OC-A error. Tried upping the motor run current to no avail. Do I need to program the no load current also (code 02-00)?
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VFD - Motor OC at startup
- Thread starter Provident
- Start date
- Replies 11
- Views 2,275
SomeoneSomewhere
Hot Rolled
- Joined
- Dec 24, 2019
You have the motor connected directly to the drive, not via a contactor or switch?
wheels17
Stainless
- Joined
- May 10, 2012
- Location
- Pittsford, NY
Have you attempted to measure the current at startup, or does it trip before you can do that?
jim rozen
Diamond
- Joined
- Feb 26, 2004
- Location
- peekskill, NY
The only possible suggestion here (other than checking to see all the load wiring is correct) is to be sure to work via the
cd-rom or online manual. In the distant past I recall that the paper manual for those drives is missing some key information.
cd-rom or online manual. In the distant past I recall that the paper manual for those drives is missing some key information.
How soon does the OC occur?
1) If it happens when the motor is actually accelerating, when it has started to run, that is one thing.
2) If it happens fast enough that the motor is not turning yet, that is different.
In case "1", the problem should be with too fast an accel time. What is the motor running? A high inertia load like a big grinding wheel, or a blower may need some cut-and-try adjustment to find a good accel time, too slow ans too fast will often BOTH fail on OC.
If possible, disconnect motor from the machine (belt, shaft coupling, etc), and see if it runs with no load using the VFD.
In case 2), there may be a wiring problem, or even a fault in the VFD.
Check the wiring for unseen wire strands that may be causing a short. If nothing, then disconnect the wires to the motor at the VFD, and then do the normal start. If it works OK, and you can adjust frequency etc, then the VFD likely is OK.
Double check wiring and motor. Reconnect wires at VFD, and disconnect at motor, put wire nuts on wire ends to avoid shorts. Run the VFD again. If it works, the wires are OK to the motor, so double check motor connections, then re-connect motor and try again.
1) If it happens when the motor is actually accelerating, when it has started to run, that is one thing.
2) If it happens fast enough that the motor is not turning yet, that is different.
In case "1", the problem should be with too fast an accel time. What is the motor running? A high inertia load like a big grinding wheel, or a blower may need some cut-and-try adjustment to find a good accel time, too slow ans too fast will often BOTH fail on OC.
If possible, disconnect motor from the machine (belt, shaft coupling, etc), and see if it runs with no load using the VFD.
In case 2), there may be a wiring problem, or even a fault in the VFD.
Check the wiring for unseen wire strands that may be causing a short. If nothing, then disconnect the wires to the motor at the VFD, and then do the normal start. If it works OK, and you can adjust frequency etc, then the VFD likely is OK.
Double check wiring and motor. Reconnect wires at VFD, and disconnect at motor, put wire nuts on wire ends to avoid shorts. Run the VFD again. If it works, the wires are OK to the motor, so double check motor connections, then re-connect motor and try again.
Jraef
Titanium
- Joined
- Aug 10, 2004
- Location
- San Francisco Bay Area
All the right advice. I'll just add that the first simple step I would take would be to disconnect the motor and try to run the drive with no load connected. If you still get an OC-A fault, it's the drive, likely a shorted transistor. If not, then it's either the motor, the settings, the connection etc.
mksj
Hot Rolled
- Joined
- Aug 10, 2010
- Location
- San Diego, CA
It would help to have the L510 model number, I assume it is a 1 Hp version which is rated at 4.3A output in HD mode. So should have sufficient current unless you motor has a short or is drawing more current then rated. Also make sure your input voltage is greater than your motor rated voltage.
I would first set the motor parameters and run the Auto-tune, which will fill in the value for 02-00.
Set parameter 00-00 to 1 (SLV) if you haven't already done so.
Set motor parameters 02-01 and 02-03～02-06 to the name plate values，next set 02-07 to【1】to start the auto tune procedure. On some VFD's you need to make the program change, exit and then hit the run key if the auto-tune process does not start when you exit the programming.
During the Auto tune the display will show AT and show END briefly when auto tune is completed then the display will return back to show frequency.
After a successful auto tune the motor test data is stored in parameters 02-08 and 02-09 and parameter 02-07 is set back to 0.
I would first set the motor parameters and run the Auto-tune, which will fill in the value for 02-00.
Set parameter 00-00 to 1 (SLV) if you haven't already done so.
Set motor parameters 02-01 and 02-03～02-06 to the name plate values，next set 02-07 to【1】to start the auto tune procedure. On some VFD's you need to make the program change, exit and then hit the run key if the auto-tune process does not start when you exit the programming.
During the Auto tune the display will show AT and show END briefly when auto tune is completed then the display will return back to show frequency.
After a successful auto tune the motor test data is stored in parameters 02-08 and 02-09 and parameter 02-07 is set back to 0.
johansen
Stainless
- Joined
- Aug 16, 2014
- Location
- silverdale wa
smoke test the motor by applying 120vac to the coils, give the motor a spin and it may start up. sometimes they don't but, you should have the same behavior regardless which 2 of the 3 phases you apply 120vac to it. (don't be a moron and do this while the motor is connected to the vfd lol!) this will not hurt the motor unless you leave it plugged in for more than maybe.. a minute i'm guessing.
there is an edge case where, the boost volts can be programmed so high that the drive will over current fault on startup, but you should still see the shaft spin, but on that particular drive it doesn't look like that will be possible for the motor that you have.
it appears to me that the default for that unit is 10% of the drive voltage (22 volts) at 1-3hz. https://www.tecowestinghouse.com/Manuals/L510_instruction_manual.pdf
its possible that you have less than 5 ohms resistance in the windings, but these drives probably have a 50% over current for 10 seconds at least.. so, you should see the motor spin and its highly unlikely this is a problem.
there is an edge case where, the boost volts can be programmed so high that the drive will over current fault on startup, but you should still see the shaft spin, but on that particular drive it doesn't look like that will be possible for the motor that you have.
it appears to me that the default for that unit is 10% of the drive voltage (22 volts) at 1-3hz. https://www.tecowestinghouse.com/Manuals/L510_instruction_manual.pdf
its possible that you have less than 5 ohms resistance in the windings, but these drives probably have a 50% over current for 10 seconds at least.. so, you should see the motor spin and its highly unlikely this is a problem.
VFD an d motor OC A fault
Thanks for all the replies and advise. long story short.... Took motor apart and looked it over well, seemed to be ok, bearings good. Reconnected to VFD , set a 30 second acceleration. As the motor accelerated, I could hear something rubbing inside when it reached a certain speed. Current exceeds run value and jumps corresponding to rub point. I think the motor shaft is bent or out of balance, and the armature is rubbing. would never know it spinning by hand, nice and smooth. Oh well, it was a nice cast iron EP motor...
Thanks for all the replies and advise. long story short.... Took motor apart and looked it over well, seemed to be ok, bearings good. Reconnected to VFD , set a 30 second acceleration. As the motor accelerated, I could hear something rubbing inside when it reached a certain speed. Current exceeds run value and jumps corresponding to rub point. I think the motor shaft is bent or out of balance, and the armature is rubbing. would never know it spinning by hand, nice and smooth. Oh well, it was a nice cast iron EP motor...
Take a better look at the innards. Look for rub marks on rotating parts, and on stator. Check the fan particularly.
It is probably worth another look, you have already determined it generally works, why not?
It could easily be that there is a washer for end play that is too thin, or even in the wrong place, so when the motor is energized, it pulls the rotor end-wise and rubs.
It is probably worth another look, you have already determined it generally works, why not?
It could easily be that there is a washer for end play that is too thin, or even in the wrong place, so when the motor is energized, it pulls the rotor end-wise and rubs.
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