Drive "Motor Temp" warning (4310)

[servospec]

I am having a problem with an ABB ACS800 vfd diplaying "Warning Motor Temp 4310)". The drive is 550kw. The motor has a cooling fan mounted and the mtor estimated temperature is (actual signals 1.37 is 93.4 deg c.) Any thoughts?

 

[DickDV]

If you know the motor temperature via actual signals then you must have thermocouples or RTDs installed in the motor. In that case, you should be using the parameters in Group 35 to inform the drive of the motor temperature.

I suspect that you have not turned off the motor overload calculations in Group 30 Parameters 04 thru 09 and these are giving you this warning.

It may also be that you have installed separate thermocouple or RTD receivers to measure motor temperature. In that case, the relay output of the receivers needs to be wired to an external fault loop on the drive digital inputs. You will not get a Motor Overtemp warning or fault with that configuration but rather an External Fault. Your fault would still be coming from Group 30 as mentioned above.

 

[servospec]

Yes, There is an RTD wired to a seperate temperature overtemp device in the control panel. This device has a relay output wired to a AB ControLogix PLC input. The drive's temperature is an estimated motor temperature. The motor protection mode is "User Mode". Group 30 has ben configured by whomever did the startup. The frequency reference is 35HZ and the motor load is current is about 85% FLA. I will look at group 35 settings ASAP.

 

[DickDV]

Well now, hold it for a moment. If the RTD's go to their own controller and then to a PLC, there is no need of looking at Group 35 since that is used to set up RTD's connected directly to the drive inputs.

I understand that the drive is set up in Group 30 Parameter 04 thru 09 to estimate motor heat but then there is also a separate RTD system watching the same motor.

Since the motor is being protected by RTD's, I don't see any point in leaving the Group 30 protection on. If you trust the RTD's, turn 30.04 to OFF and your problem will go away.