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E-13
Technical Specifications
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames E & F
Electrical Ratings: 890CS - Calculation
The required rating for the 890CS input stage can be calculated by adding up the sum of the motor
currents attached to the associated output stages.
For example:
if a 45kw 4 pole, 400VAC motor has a FLC of 82A,
and a 90kW 4 pole, 400VAC motor has a FLC of 157A.
Then a system with 1 x 45kW motor and 1 x 90kW motor has a total load current of 239A, which is
greater than the single 162A 890CS input stage rating. This example would need to use 2 x 162A 890CS
input stages in parallel.
But, if it is known that the 45kW motor is overhauled during normal operation, then that motor current
can be subtracted from, and not added to, the total load current.
In this case, total load current would be reduced to 75A. This is within the rating of a single 108A 890CS
input stage.