ReplySounds like the Decelleration time is too short. I am an ABB factory trained tech and thats usually the case with them
Professional Member
im working on a frequency drive made by teco pa7300 380-460v motor is 15 hp. my sistuation is that they test the fire alarm motor starts to ramp up good. The exhaust fan extracts all the smoke no problem once they reset the smoke alarm at the pannel and the motor starts to ramps down and a fault code pops up fault over voltage. and it will pop up like 3 consecutive times then lock out on fault over voltage. i just downloaded the manual tonight and will head back tomorrow. i have a feeling i might have to change some parammeters. has anybody alse came across this issue?????? Any advice is highly appreciated!!!
Professional Member*
Sounds like the Decelleration time is too short. I am an ABB factory trained tech and thats usually the case with them
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I agree, what's your deceleration time?
Professional Member
decelleration time 1 was set to 10.0 seconds and decell time 2 was set for 90 seconds. i lowered the decell time #2 to 20 seconds and it still gives the fault. i wanted to change a few other parameters but the engineer said he only got the approval for 2 false smoke alarm test for the day. need to return tomorrow wednesday 10/26 and try it again. I appreciate all your help and inputs thanks alot!Originally Posted by CE-TECH
Professional Member*
You need to INCREASE your deceleration time, not decrease it. Set your deceleration time #2 back to 90 seconds and INCREASE your deceleration time #1 up to something like 30 or 60 seconds.
10 seconds is too short for a fan because the inertia in the fan takes longer than 10 seconds to wind down. This turns the motor into a generator and back feeds voltage into the drive which causes the DC bus overvoltage.
Professional Member*
R123 is correct. Generally an ABB VFD has a default Deceleration time of 30sec. Depending on the size of the blower wheel I have gone as far as 60 sec.
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Professional Member
i really appreciate your help ce-tech, and R123. ima go back sometime this week and increase the decell time. I was understanding it backwards. but from your point of view it makes more sense. ill keep you two posted!! Thanks.
Professional Member
As said above raise the deceleration to minimum of 60 secs or change stop from ramp to coast if all the motor is for smoke purge.
Regular Guest
have you megged the motor windings yet. Had the same problem and the decel time was adjusted made no diffrence. The motor was causing a odd back EMF the drive did not like and would lock out over current. MEG the motor to see the diffrence in the windings. Changed the motor problem went away.
Professional Member*
Set it up for coast to stop like 69 said.
“If your work speaks for itself, don't interrupt.” ~Henry J. Kaiser
"Highly efficient equipment and LEED Bldgs are very expensive to maintain in order to keep that efficiency!" ~ Me
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ill put this threade in my brain for future referance
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