Motor/frequency driver cable size for UL508A

[larsahl]

I'm having a bit trouble to understand what cable size to select to the UL508A standard.
It is a UL508A electrical cabinet with an input of 400V or 480V AC with 50 or 60 Hz to a frequency driver from allen-bradley.
The marking plate on the driver states 20.6A input and the manual says 22A continuous output. Seems strange to me that the output is more than the input. However what I understand is the 20.6A shall be multiplied the 1.25x which are about 26A, with that value I shall select a cable in the table 28.1 which shows me wire size AWG 10 for 30A copper wire at 75 degree Celsius. The table doesn't provide me any information for wires that are certified to 90 degree Celsius. Is there any updated table or a other table that I can use for UL508A? Seems to be quite big wire for caring 26A.

Ok now for the motor side. The motor have a FLA of 14.6A and continuous stall current of 20.6A.
Shall I calculate that cable for 14.6A or 20.6A times (1.25x)?

 

[petersonra]

I'm having a bit trouble to understand what cable size to select to the UL508A standard.
It is a UL508A electrical cabinet with an input of 400V or 480V AC with 50 or 60 Hz to a frequency driver from allen-bradley.
The marking plate on the driver states 20.6A input and the manual says 22A continuous output. Seems strange to me that the output is more than the input. However what I understand is the 20.6A shall be multiplied the 1.25x which are about 26A, with that value I shall select a cable in the table 28.1 which shows me wire size AWG 10 for 30A copper wire at 75 degree Celsius. The table doesn't provide me any information for wires that are certified to 90 degree Celsius. Is there any updated table or a other table that I can use for UL508A? Seems to be quite big wire for caring 26A.

Ok now for the motor side. The motor have a FLA of 14.6A and continuous stall current of 20.6A.
Shall I calculate that cable for 14.6A or 20.6A times (1.25x)?

UL508a does not allow you to use 90 Deg C ampacity values. In fact for the most part there are very few terminations listed for use at 90 Deg C < 600V.

It is not unusual for the output current of a drive to exceed the input current. The power factor on the input is close to unity and the PF to the motor is not.

#10 75 Deg C conductors would seem appropriate.

For the motor side you have to use the motor charts provided in UL508a to determine the required ampacity. In general none of the field wiring is part of the control panel so all you have to worry about is the field terminals and those are already provided on the VFD so you should not have to do anything at all on the motor side.