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vfd turns on hertz but no voltage or amperage

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Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Jraef,
I know this is old and the OP is long gone but is it possible that the overload tripped either in the drive or if it has one in the bypass assembly? I would imagine it would throw an alarm but I'm not sure, particularly if it was in the bypass section.
If the drive electronics tripped in OL, it would not ramp up, it would show the fault. If there was a bypass, I would have HOPED that the OP would have mentioned that… But that’s a good point. If there was a bypass, the VFD output would be isolated from the motor leads and be exactly the same as having an open circuit. Then if that bypass starter was tripped in OL, nothing would be happening.

It also occurred to me that in days gone by, ABB drives used to have a feature called “Base Block” which shunted the base emitter to the transistors, immediately disabling them. Other drive mfrs do the same thing, calling it an “enable” circuit and it required a jumper between two terminals to allow the drive to function. Maybe that jumper came out or was removed by someone who didn’t realize what it was. Usually though the drive gives you some sort of error code indicating that it has been disabled, but the the ABB ACS355 is an “entry level” drive so maybe not? Who knows.
 

garbo

Senior Member
Working with an ABB ACS355 drive and when I turn it on, it comes up to 36.8 hertz which is correct but I am not getting any voltage out to the motor or amperage output. I have already ordered a replacement drive but wanted to know if anyone could educate me on what is wrong internally with my drive. When it comes up to the hertz, it just sits there with no output and no faults. I have checked all the wiring going out and ohmed out the motor and everything there checked good. Any insight would be appreciated.
I always talked to drive service techs but always got the run around with ABB. Took me two weeks several phone calls & emails just to let me know how to locate DC buss voltage that we had to insert on our once to quarterly drive PM'S. Had a few old drives that parameters would get changed on their own that drove me crazy troubleshooting. They were obsolete drives where they had LCP'S ( local control panels = fancy name for touch screen ) cooling fans and the 1 to 3 contactors. Bypass drives especially types with test position all have 3 contactors.
 

milmat1

"It Can't Do That !"
Location
Siler City, NC USA
Occupation
Controls Engineer
I have always found it best to first reset the VFD to factory parameters (Initialize) before beginning. Always !
Then set the parameters you need. This has saved me many many times ..
 
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