BENSHAW RediStart EXEXMVRMX3 Series, Руководство пользователя

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Description
The Imbalance Delay parameter sets the time that the current imbalance must be greater than the Percent
Imbalance (PFN 05) parameter before a trip will occur.
See Also
Current Imbalance Trip Level (PFN 05) on page 78.
Residual Ground Fault Trip Level PFN 07
LCD Display
Range Off, 5 – 100 % FLA (Default: Off)
Description
The Residual Ground Fault parameter sets a ground fault current trip or indicate level that can be used to
protect the system from a ground fault condition. The starter monitors the instantaneous sum of the three line
currents to detect the ground fault current.
Ground Fault Trip: The EXMVRMX
3
will trip with a ground fault indication if:
- No other fault currently exists.
- Ground fault current is equal to or greater than the GF Trip Level for a time
period greater than the GF Trip Delay (PFN 09).
Once the starter recognizes a ground fault condition, it shuts down the motor and declares a Fault 38 (Ground
Fault).
If a programmable relay (I/O 01 - 08) is set to "Ground Fault", the starter energizes the relay when the
condition exists.
A typical value for the ground fault current setting is 10% to 20% of the full load amps of the motor.
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NOTE: This type of protection is meant to provide machine ground fault protection only. It is not meant to
provide human ground fault protection.
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NOTE:
The EXMVRMX
3
residual ground fault protection function is meant to detect ground faults on
solidly grounded systems. Use on a high impedance or floating ground power system may impair the
usefulness of the EXMVRMX
3
residual ground fault detection feature.
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NOTE: Due to uneven CT saturation effects and motor and power system variations, there may be small
values of residual ground fault currents measured by the EXMVRMX
3
during normal operation.
See Also Ground Fault Trip Time parameter (PFN 09) on page 80.
Auto Reset parameter (PFN 23) on page 84.
Controlled Fault Stop Enable parameter (PFN 25) on page 85.
Relay Output Configuration parameters (I/O 10 - 15) on page 91.
79
6 - PARAMETER DESCRIPTION
PFN: Resid GF Lvl
07
Off
Alarm
Condition
Fault
Trip
% FLA
Ground Fault
Trip Time
PFN 09
Residual Gnd Fault
Level
PFN 07
Time