Hi Tom, to nip this in the bud, can you post a photo of the new motor rating plate and an archive of the drive parameters? Is the old motor identical in EVERY other way barring the kW & Amps? If not, post a photo of that as well.

If possible, can you upload a parameter set that is captured whilst the drive is running and indicate what speed you actually intended, that way, a setpoint path analysis can be undertaken.

Regards,

Graeme

What I do when things are not correct is I launch Sinamics Starter, go online with the problem VFD, and open Drive Navigator.

I watch the speed setpoint coming via telegram all the way through the drive's model to the motor.

If it changes, I figure out why and fix it.

If it stays the same and is not correct, I fix my PLC speed setpoint scaling so the PLC is sending the value the VFD expects, or fix the P2000 rated speed for what 100% speed setpoint should represent.

For you, p2000 is 975 rpm (rated speed @ 50Hz) if I have understood correctly.

The PLC should be scaling 975 RPM or 50 Hz to 16#4000 for telegram speed setpoint.  I verify nothing in the PLC logic is writing to the speed setpoint word except your telegram handler logic (in one place).

Then, I make sure the VFD is receiving the same value for speed setpoint that the PLC is sending.  FYI, if I'm using StartDrive, some of the above is handled automatically so gets skipped over.

Once I know the 16#4000 speed setpoint (100% / rated speed) command is received via telegram, then it is a matter of internal setpoint scaling which is all p2000.  That said, there are some odd settings that are only found by reviewing the motor models available in F1-help in Starter for various parameters, like speed setpoint.

I find the correct motor model diagram for my VFD (G120 or G120C?) where speed setpoint is generated.  There are some values in there that get can altered and then stuck when people commission the VFD incorrectly, then recommission it without resetting to factory defaults first.  There are some parameters which get left in a changed state and are not readily found until a thorough review of the speed setpoint control diagram is done.

Graeme

Hi Tom, to nip this in the bud, can you post a photo of the new motor rating plate and an archive of the drive parameters? Is the old motor identical in EVERY other way barring the kW & Amps? If not, post a photo of that as well.

If possible, can you upload a parameter set that is captured whilst the drive is running and indicate what speed you actually intended, that way, a setpoint path analysis can be undertaken.

Regards,

Graeme

New motor rating plate attached. I'll upload a picture of the old motor plate on another post.

For some reason, in the inverters parameters in TIA portal the "Export displayed list in CSV file" option is grey, is there another method of obtaining an archive of the parameters for you?

Just an quick update. 

Found the issue. There was a some code that had been erased at some point which multiplied the frequency input at the HMI by 2 before being sent to an Analog OUT function for scaling, so we were always getting half the value we input.

Thanks to everybody for your assistance on this, its helped me out greatly.

Tom.