# powerflex 400 fault



## John Valdes (May 17, 2007)

Can you operate this drive without the motor connected? If so, this will tell you if its drive related or not.


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## ScooterMcGavin (Jan 24, 2011)

I haven't tried it. The compressor contractor is coming out to look at it, but I wanted to be armed with some information before they get here as they haven't been the most knowledgeable about the electrical/control aspects of the compressors.


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## varmit (Apr 19, 2009)

It sounds like the compressor is trying to start loaded- air head pressure not relieved.


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## JRaef (Mar 23, 2009)

F12 just means that the current is attempting to go higher than the hardware based current limit of the VFD, meaning higher than the overload rating of the drive. In the case of the PF400, that is either 180% of the VFD's max amp rating for 3 seconds, or 220% instantaneously. If the compressor is locked rotor and you have an aggressive ramp profile, that could explain it.

John's suggestion of trying to operate it with the motor disconnected from the VFD will tell you if it is a damaged drive IF you still get the fault with no motor disconnected. If the fault is not there, easy step 2 would be to connect ANY other motor you have handy and see if it can spin that. If so, then you have a problem in the compressor or compressor motor.

Wherever you heard that it immediately indicates that the drive is damaged is incorrect. That is the LAST thing it would mean, AFTER you eliminate all other the more probable causes, such as locked rotor, excessive load or an overly aggressive V/Hz curve setting.


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## oliquir (Jan 13, 2011)

but vfd should show some voltage and current reading before it gives error. if it is instantaneous the vfd is probably bad


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## ScooterMcGavin (Jan 24, 2011)

The weird thing was that the VFD didn't even seem to be trying to start. As soon as you would hit the start button the VFD instantly went into the fault even though nothing happened and it didn't even seem to attempt to start the motor, 0Amps, 0volts, 0Hz on the fault data. 

The compressor was spinning free so we lifted the wires tried it and it worked. hooked the wires back up and it ran fine. We were resetting the faults on the VFD control panel, but does cycling the power do something different as far as clearing faults goes?


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## denny3992 (Jul 12, 2010)

Not sure about te pf400 but some drives will still operate small hp motors an fault on the right size motor....

Had a 250 hp drive out of box that faulted when connected.. Hooked a 20hp and it worked.... Turned out it was something in the firingboards that would work on small but not when u got to higher currents


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## KennyW (Aug 31, 2013)

scameron81 said:


> The weird thing was that the VFD didn't even seem to be trying to start. As soon as you would hit the start button the VFD instantly went into the fault even though nothing happened and it didn't even seem to attempt to start the motor, 0Amps, 0volts, 0Hz on the fault data.
> 
> The compressor was spinning free so we lifted the wires tried it and it worked. hooked the wires back up and it ran fine. We were resetting the faults on the VFD control panel, but does cycling the power do something different as far as clearing faults goes?


Sometimes. I've seen this on Powerflex 700S (mind you I've seen so many weird faults on those drives there's too many to count). 

Whatever thermal memory is inside the drive gets stuck at max and doesn't actually clear until a power cycle.


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## JRaef (Mar 23, 2009)

scameron81 said:


> The weird thing was that the VFD didn't even seem to be trying to start. As soon as you would hit the start button the VFD instantly went into the fault even though nothing happened and it didn't even seem to attempt to start the motor, 0Amps, 0volts, 0Hz on the fault data.
> 
> The compressor was spinning free so we lifted the wires tried it and it worked. hooked the wires back up and it ran fine. We were resetting the faults on the VFD control panel, but does cycling the power do something different as far as clearing faults goes?


There are two types of faults; type 1 are general faults, type 2 are those that might involve possible hardware damage. If the drive determines that a fault, or series of successive faults, may have been the result of, or WILL possibly cause hardware damage, it will categorize it (or the last one in the string) as a type 2 fault. That means it will not allow remote reset, only cycling the power will reset it, because that forces the power circuit self-check diagnostic routine that the drive goes through at power-up.


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