DEMA CPM 310 G, User Manual

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Testing & Maintenance & Reparation
Under normal service conditions, no testing or maintenance action is required for CPM 310 G. If under
a supernormal condition CPM 310 G becomes unstable or out of service, testing, maintenance or
reparation of the unit may become essential.
Test Process of CPM 310 G
 Primarily, supply auxiliary power to CPM 310 G to initiate the test process. If the auxiliary power is
supplied by local devices, test them to ensure the healthy supply. If CPM 310 G does not start up
and there is no “Power” LED signal; possible causes are supply circuit faults or the burn out of
CPM 310 G fuse. Analyze those possibilities and take the corrective actions; if the problem is
caused by the CPM 310 G fuse, replace it by a new one with specifications Ø5 mm x 20 mm T1A
(see p.19). Examine the possible causes of supply overcurrent that made the fuse burn.
 If there is no possibility of employing an appropriate relay test device for testing CPM 310 G, use
the
Function Test
option from the relay menus (see p.126).
Function Test
option generates
imaginary overcurrent and conditions, and tests the functions in services to find out whether the
relay is functioning in the desired way or not. If any protection function is active, function test will
result in tripping of the circuit breaker; consider this and set appropriate trip settings to “passive”
temporarily (see p.106) to prevent tripping of the primary circuit.
 If detailed tests are required to be carried out, use of a high-sensitivity, low-error relay test device
is essential. In this case, trip time delays should be measured independently to confirm the
correct operation of the relay. Tests must include the measurements for protection function trip
delays, positive and negative sequence current measurements; broken conductor and thermal
overload functionalities, input and output configurability.
 In the case a failure is figured out on CPM 310 G, or no specific failures are found while the relay
is not operating correctly, get in touch with DEMA Relay Industries technical services. □