IMM 8001/8002 – Digital Motor Protection Relay
ICE / CEE
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IMU307-1 GB Ind. B
81
TESTS : Verification of UNDER VOLTAGE AFTER START PERIOD protection [27]
CONNECTION
Protection verification
Voltage generator connected to terminals 19–21
Current generator connected to current input phase 1 or 3 so that normal operation after start can be simulated. Identical simulation with
EL1 input activation.
No voltage coefficient of correction.
Sequence of operations to be performed
Results to be obtained
Simulate normal operation of the motor with the instantaneous application
of an Ipos current equal to at least 1.5 In (start), then by decreasing
the Ipos current to a value close to In (normal operation), or wait for
a time greater than
2tst>
or Simulate motor operation by ap24V to the
EL1
input (wire between
terminals A3 and B18), and wait for a time greater than
2tst>
The under voltage function after the start period is now permanently active.
This function is inhibited when the current is cut off, or when
EL1
is deactivated.
Check of under voltage unit after start
Check of operating level U<
Put into service the protection, and route it to a chosen unit.
Note the value of operating level
U<
Check that starting is ended to start the verification.
Apply a voltage greater than displayed operating level
U<
Gradually decrease the voltage down to operating level
U<
If necessary, check the U13 value on the display during the injection.
Check of time-delay tU<
Note value
tU<
Preset the voltage to 1.2 times the displayed operating level.
Cut off the voltage injection only: time-delay tU< must be started at this
time.
the Start Function indicator LED illuminates on reaching
the displayed operating level.
At the end of the set time-delay :
the selected relay must be energised,
the Internal Trip indicator LED must
illuminate,
the fault message and related information must
be displayed.