Sevcon MillipaK 4QPM Manual page 58

Controller Protection
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Motor Protection Cutback
By monitoring the motor current over a period of time, the controller then calculates the total
power dissipation within a typical motor and so estimates the motor temperature rise.
After setting Motor Protection Cutback to ON, the estimated motor temperature can then be used
to set the maximum allowed motor current and thus prevents excessively high motor temperatures
being reached.
The maximum allowed motor current will reduce down to a minimum of 30% of the Armature
Block rating if the estimated Motor Temperature rises to a dangerous level.
If Motor Protection Cutback is set to OFF then there will be no reduction in allowed maximum
motor current due to estimated motor temperature, although any other forms of maximum current
reduction (such as thermal cutback) will still be applied.
The Upper and Lower Limits set the cutback levels. The maximum allowed current is linearly
cutback between the two levels. As the levels are reduced the maximum allowed current will be
cutback earlier.
Motor Protection Cutback
Calibrator Menu Reference:
Options
OFF
Current Cubed Lower Limit
Calibrator Menu Reference:
Minimum Maximum
0 254
Current Cubed Upper Limit
Calibrator Menu Reference:
Minimum Maximum
1 255
MillipaK 4QPM Controller Manual
ON
Step Size
1
Step Size
1
POWER UP
12.09
Default
OFF
Immediate
8.01
Typical Value
25
Immediate
8.02
Typical Value
40
Page 58
Motor Protection Cutback
13/08/03