I-Gard MGFR Series, Инструкция по эксплуатации, Страница: 14 / 24

6. INSTALLATIONS
6.1 SITE REQUIREMENTS
MGFR receives a current input signal from the secondary of one of the zero sequence sensors described in section
3. The sensor should be selected according to the busbar/conductor size and the model of MGFR being used. The
sensor should be placed in the panel where the busbars/conductors are accessible. All three phase conductors
and the neutral must pass through the window of the sensor. The relay should be mounted on the front side of the
panel. Wiring from the secondary of the sensor are to be brought to the X and X1 terminals (W1 and W2 in case of
MGFR-SE-ZB) of the relay. See Fig. 5 and Fig. 6 for interconnection detail. Wiring connections should be made with
standard switchboard No. 14 SWG copper wire to the external terminal blocks on the rear of the MGFR. For MGFR-
SE-ZB Types the TEST winding R3, R4 on the Type RZ ZSCT should be connected for primary injection testing, as
required by code.
Note: For proper operation of the MGFR relays, the chassis should be grounded.
6.2 MOUNTING
The MGFR relay should be located in a position not subject to dirt, corrosive fumes or temperatures outside the
specified limit. The relay should be mounted in a 159 mm x 108 mm (6.25” x 4.25”) cutout on the compartment door
of the panel within reach of an observer or operating personnel. This is shown in Fig. 7. First, remove the “C” shaped
mounting bracket from the back of the MGFR, install the MGFR on to the relaying compartment door from the front
and through the cut out, refasten the mounting bracket on to the MGFR with the two No. 6-32 retained screws
provided. Tighten the screws so that the relay sits flush with the compartment door.
When the unit is in position and powered up, the display should, ideally, show ‘0.00’. Check the relay operation by
pressing the SELF TEST button to ensure that the unit is working properly. See Section 2.6.2.
7. MAINTENANCE
7.1 GENERAL
Each MGFR relay is tested before shipment. It is ready to be used after it has been inter-connected with the ZSCT
and the other components of the trip unit, and the appropriate settings have been selected.
The only maintenance recommended is the periodic verifi cation that the relay is functioning. Usually, the visual LED
display is a good indication of its proper operation. If the display shows ‘0.00’ or any value up to ‘0.10’, this situation
is normal. The verifi cation may further be supplemented if so desired by the following procedures:
a) For models having TRIP INHIBIT facility, perform the SELF TEST operation explained in section 2.6.3.
b) For MGFR-1-ZB models not having TRIP INHIBIT facility, perform the SELF TEST operation if the Breaker can
be tripped without incident.
c) If discontinuity of supply during SELF TEST operation in b) is not desirable, you may avoid this test, or
disconnect the trip circuit of the breaker involved.