50
Electronic Motor Protection Relays
Condition
Red O.L LED
Remarks
Operation normal
Off
Overcurrent
Flicker
Flicker during overcurrent
Trip over-current
On
The EMPR is tripped
3. Set the operating time
D-Time (Delay Time) : 0~30 sec
It refers to the time of delaying EMPR operation in order to prevent Trip from a motor’s staring current.
1) With the use of D-Time Knob, set up a delay time taken from motor starting to normal running current.
2) If you are unaware of a start delay time, set it to the maximum time and measure how long it takes to reach the normal starting current of the
motor, and then set it up again. (Reference: in case of general load, set it to about 3~5 seconds.)
Note) If actual load current fails to detect during a set time, a motor can be damaged. Set up a delay time rightly.
O-Time (Operating Time) : 0~15 sec
It refers to the time taken from the start of overcurrent to EMPR Trip. After the set O-Time, EMPR is Tripped.
1) With the use of O-Time Knob, set up an operating time.
2) If O-Time is the minimum value, EMPR is immediately tripped as soon as overload occurs. (Reference: generally, set it to 4~6 seconds.)
A-Time (Auto Reset Time): 0~120 seconds; set up an automatic reset time in auto reset type.
4.
Set the operating current
Setting is based on the rated current of a motor (normal operating current).
1) Check that a motor’s rated current is within the current control range of EMPR.
2) Set RC (Rating Current) Knob up to the maximum and run the motor.
3) In normal operation state, slowly turn RC Knob counter clockwise and stop at the point that overcurrent display lamp (O.L) flickers. At this point,
the actual load current value (100%) of the motor is displayed.
4) From the point, turn RC Knob clockwise. Set up the knob at this point that O.L lamp is turned off (less than motor full load current).
Generally, set it to 110~120% of actual load current (set to a value lower than a motor full load current).
5
.
Check the LED condition when operation
1) GMP60T
Definite time characteristic 1
1
.
Check the rated voltage and
apply the control power to A1
and A2 terminal
If 220V power is supplied to a model for
AC110V, overvoltage occurs and thereby
EMPR has a failure.
2. Check the Test/Reset button
operation
1) If Test/Reset button is clicked once, O.L
(display lamp) is turned on, EMPR is
Tripped, and output contact runs.
2) If Test/Reset Button is clicked once again when EMPR is Tripped, the display lamp is turned off and the equipment returns to its original state
(Reset).
Note) 1. To prevent a Trip accident, Test/Reset button is designed not to work while a motor is running. 2. If Test/Reset button is clicked twice within 0.5 second, it is possible to check the final failure cause.
2) GMP60-3T/3TR
The same as the LED operation state in operation.
current(s)
time(%)
Test/Reset button
O-Time knob
RC (A) knob
D-Time knob
O.L LED
Operation
&
setting method