Powerflex 753 drive overload fault

[Elijah58]

Guys,
I have a powerflex 753 25hp that we installed replacing a powerflex 700 25hp. we had a short that took out the drive and we installed a powerflex 700 20hp just to get by till we got the 753 in. the 20 hp seemed to work fine except when we got into a heavy load and then would fault at about 29 amps. when we installed the 753 everything seemed ok but started getting a "Motor Overload Fault" and shutting the machine down. Parameters in the 700 25hp and the 753 25hp. are the same but it is kicking out at around 23 amps. motor is 460 V rated at 25hp 26FLA. Has anyone run across this issue with this drive.
Thanks in Advance,
Eli

 

[jraef]

Did you re-do the Autotune procedure on the new 753 when you installed it?

 

[Elijah58]

Yes, the autotune was done.

 

[kamenges]

Are you running at a speed that results in an RPM below 20 Hz? The drive comes with a default configuration that assumes a TEFC motor construction. The drive applies a derating curve to the continuous current at at output frequencies below 20 Hz. This can be configured so it is effectively ignored.

Keith

 

[rdrast]

The PF 750's are EXTREMELY sensitive to just about everything out of the box. Check P413, "Mtr OL Factor", it defaults to 100%, I bump it up to at least 125.
Actually, I have had to go so far as to set the Motor OL Actn (P410) to "Alarm".

While you are at it, take a look at P463 "InPhase Loss Lvl"... That I set at 1000, and also set the "InPhase LossActn" (P462) to "Alarm" as well.

Then there is also P409 "Dec Inhibit Actn" that I also set to either ignore or Alarm.

 

[Elijah58]

Thank you, running at 21 amps and 4.5hz

 

[Elijah58]

That worked so far, i think that may be the answer.
Thanks guys for everything,
Eli

 

[kamenges]

Before you end up buying a new motor because you cook the one you have, what is your motor construction?

Keith

 

[Elijah58]

Not sure what u are asking?
Eli

 

[JaxGTO]

I have seen about a 10% failure of PowerFlex drives OUT OF THE BOX. I would start a tech support ticket which you will need to exchange it.

 

[ianingram]

Not sure what u are asking?
Eli

Do have forced cooling on the motor running at 4.5Hz?

 

[Elijah58]

Do have forced cooling on the motor running at 4.5Hz?

No i don't, should I? I noticed the motor running fairly warm the last couple weeks.
Eli

 

[ianingram]

Yes, you should have forced cooling for an electric motor operating at low Hz.
At 4.5Hz, the motor fan will not be producing enough airflow to cool the motor.

I was looking for a relevant link...
If it is a SEW motor, it is mentioned on this page:
http://www.sew-eurodrive.com.au/produkt/accessories-and-options-for-motors.htm

 

[Elijah58]

RDRAST Thank You, This has solved the problem, we have run production since yesterday without any issues whatsoever. I am so greatful to have a site like this to come to for help, It has helped me many times, just wish I was a little more knowledgeable to be able to give something back.

ianingram: the motor is a BLUE MAX, on a SEW gearbox.
Thanks Again,
Eli

 

[kamenges]

Blue Max motors in that horsepower rating are TENV (totally enclosed non-ventilated) construction. They are physically designed to dissipate all the heat they generate down to zero speed without air-over cooling. So you are good.

Keith