PowerFlex755 no torque

I am trying to startup a PF755 with a 400hp motor.
I did the startup wizard and all the auto tunes with the motor uncoupled. It runs and follows speed when uncoupled fine. It has one DI card for giving a "permissive" signal.
When it's coupled and I reference say 30 Hz, the motor spins as it should until it runs into the current limit. Speed stops at 25 Hz, and then when the amps start to come down it tries to speed up to speed setpoint. The motor can be turned hand while coupled, freely turns.
Uncoupled the motor is using a max of 110 amps, works like a charm.
I have the same drive model running two other 350 hp drives with no problems. Have verified the motor wired correctly, and compared the setup to the other drives.
The drive is doing all that it should be as it tries to boost speed but shuts down on current limit. As it should...
The low torque, with exceptionally high amperage has me scratching my head.

Could you send parameters of your drive in pdf?

What is the FLA of the 400hp motor and what is the current rating of the drive, it may be big enough for the 350hp motors but no big enough for the 400hp motor.

Alan

a062549 said:

I did the startup wizard

Click to expand...

Would that be energy saving mode?

Not sure what your voltage in China is, here in the US our volts to Hz ratio is 7.666 volts to the Hz. When you are experiencing the problem, check your output volts against the amps. If it's considerably below your volts to hz ratio you need to not use the energy saving startup wizard.

Sounds as though you have inadvertently set a torque limit in programming. Uncoupled, the motor can get to 110A because that is mostly reactive current, not torque producing current, the drive will know the difference if you are in any kind of Vector mode. So under load, the torque producing current is hitting that limit and overriding your speed command, which is exactly what it is supposed to do. I don't have my manual here to look, but there is a parameter for torque limit, check the value you have it set for.

Update!

So the AB Service person comes by to look at the drive issue.

He says, "Oh, its in Param 35, it sould be Induction SE, not V/Hz. And not pump/fan!
I replied "but it is a pump"(?)

We changed it to Sensorless Enhanced and Custom vhz, Paramerters 35 & 65. BANG it works as it should...

We changed the others to the custom v/Hz too. All good now.

Thanks for the replies!!
J