there is a small
further movement
of the
armature.
This ensures that contact follow
through
and wiping action is present. On units fitted with hand reset flag indicators,
check the flag is free to fall before, or just as, any normally open contacts touch.
Check that the external wiring is correct to the relevant relay diagram or
scheme diagram. The relay diagram
number
appears inside the
case.
Particular attention should be paid to the correct wiring and value of any external
resistors indicated on the wiring diagram/relay rating information.
Note that shorting switches shown on the relay diagram are fitted internally
across the relevant case
terminals
and close when the module is withdrawn. It is
essential that such switches are fitted across all CT circuits.
If a test block type MMLG is provided, the connections should be checked to the
scheme diagram, particularly that the supply connections are to the ‘live’ side of the
test block (coloured orange) and with
terminals
allocated with odd
numbers
(1, 3,
5,
7, etc.).
Earthing.
Ensure that the case earthing connection above the rear
terminal
block, is used
to connect the relay to a local earth bar.
Insulation.
The relay, and its associated wiring, may be insulation tested between:
a) all electrically isolated circuits
b) all circuits and earth
An electronic or brushless insulation tester should be used, having a dc voltage
not exceeding 1000V. Accessible
terminals
of the same circuit should first be
strapped together.
Deliberate circuit earthing links, removed for the tests, must subsequently be
replaced. Terminal allocation.
Terminals of the relay are normally allocated as below, but reference should
always be made to the relevant diagram.
a) Single pole relays
Normally open contacts 1, 3 and 2,
4.
AC current input – 27,
28.
An alternative version of the relay has additional normally open contacts
connected to 5, 7 and 6,
8.
b) Triple pole relays
Normally open contacts 1, 3 and 2,
4.
The contacts are normally connected in parallel for the three phases but
a version of the relay having contacts brought out separately is available.
AC current inputs
-
23, 24 : 25, 26 : 27,
28.
2.2 Instructions to ensure that the relay can be commissioned at the specific
settings for the application
It is only necessary to check the relay at the setting on which it is to be used.
The relay
must
not be used at any setting other than that for which the setting has
been calculated.
12
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