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
T
VxC .
.
768
.
1
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 =
R
xR
249
249
ohms
For firmware revisions of 5.00 and above:
C.T. burden line =
R x
r
PulseNumbe
6
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
.
1
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 =
R
xR
249
249
ohms
For firmware revisions of 5.00 and above:
CT burden motor = R ohms
Select the nearest standard resistor value.