Parameter and variable descriptions – Rockwell Automation 1557 MEDIUM VOLTAGE AC DRIVE User Manual

Page 76

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PARAMETER AND VARIABLE DESCRIPTIONS

1557-UM050F-EN-P – June 2013

CT Burden Line [CT burden line]
Linear number:

151

Minimum value:

1.0 ohms

Maximum value:

1000.0 ohms (FRN 5.xx)

6300.0 ohms (FRN 4.xx)

Default value:

15.0 ohms

This parameter specifies the value of the scaling resistors for the line current feedback.
To determine the required value for the scaling resistors, first calculate the equivalent scaling resistance using
the following formula:

R =

Amps

RatedMotor

Ratio

VxC .

768

ohms

Because of hardware differences between the original Drive Control board and the new 18-pulse Drive Control
board, the actual value of resistor required depends on the firmware version:

For firmware revisions less than 5.00:

C.T. burden line =



249

ohms

For firmware revisions of 5.00 and above:

C.T. burden line =

R x

PulseNumbe

ohms

Select the nearest standard resistor value.

CT Burden Motor [CT burden motor]
Linear number:

152

Minimum value:

1.0 ohms

Maximum value:

1000.0 ohms (FRN 5.10)

6300.0 ohms (FRN 4.xx)

Default value:

39.0 ohms

This parameter specifies the value of the scaling resistors for the motor current feedback.
To determine the required value for the scaling resistors, first calculate the equivalent scaling resistance using
the following formula:

R =

Amps

RatedMotor

VxLEMRatio

768

ohms

Because of hardware differences between the original Drive Control board and the new 18-pulse Drive Control
board, the actual value of resistor required depends on the firmware version:

For firmware revisions less than 5.00:

C.T. burden motor =



249

ohms

For firmware revisions of 5.00 and above:

CT burden motor = R ohms

Select the nearest standard resistor value.