I-Gard MGFR Series, Инструкция по эксплуатации, Страница: 9 / 24

This feature is standard in all models of the MGFR series. However, the method of self test in MGFR-SE- ZB is
different from the rest of the models.
2.7.2.1 MGFR-(1, 2, 20, 200, 1200)-ZB Types
There is a built-in test facility by a SELF TEST pushbutton on the faceplate of the relay. The self-test will
ensure the proper operation of relay circuitry, energize the trip contact, and light up the indication.
However, this will not erase the last fault current value that is stored in the memory, if any. Proper
operation of the relay is indicated by a display reading of 1.1.1 for a few seconds after the SELF TEST
button is pressed.
The TRIP indicator light is reset by the TRIP RESET switch after the relay returns to normal and shows
‘0.00’.
2.7.2.2 MGFR-SE-ZB
The TEST winding terminals R3 and R4 of the RZ sensor (used normally with the MGFR-SE-ZB relay) are
connected to R3 and R4 terminals of the relay to provide Primary Injection Testing (See 3.3). To energize
the TEST winding the control supply to the relay has to be sufficiently rated to provide the TEST Current of
approximately 10 amperes at 120V, 60Hz. as shown in Fig. 6. The SELF TEST is designed to operate at any
pick-up and time settings. When the SELF TEST button on the relay is operated, a TEST current will flow in
the relay for the duration as set by the time-setting switch. The value of the current will show in the display
in per unit for a few seconds after the relay has tripped. The relay ‘knows’ that this is a TEST current and not
a FAULT current. So, this value will not be stored in the memory. The breaker will trip and the trip target will
come up.
If R3 and R4 terminals are not connected to the RZ sensor, no test current will flow in the relay when the
SELF TEST button is pressed and the relay will flash five times showing ‘0.0.0’. The breaker will not trip
but the trip target will come up.
The target can be reset by pressing the TRIP RESET button momentarily.
2.7.3 TRIP INHIBIT
Available to the models MGFR-20-ZB, MGFR-20-AB, MGFR-200-ZB, MGFR-200-AB, MGFR-1200-ZB, MGFR-
1200-AB and MGFR-SE-ZB.
This switch provides a convenient way of testing the system without operation of the breaker when the
continuity of the supply is to be maintained during self test operation.
The pushbutton on the faceplate may be used to INHIBIT the trip circuit of the relay to be energized, during the
SELF TEST operation. Pressing the TRIP INHIBIT button and holding it pressed BEFORE pressing the SELF
TEST button will prevent tripping the breaker.
WARNING
OPERATION OF THE SELF TEST WILL CAUSE THE
ASSOCIATED BREAKER TO TRIP unless the TRIP INHIBIT button
is held down for the entire duration of the test.
2.7.2 SELF TEST