21
2.4
Method of Operation
2.4.1 Connect the equipment via the mains cable provided, to a 3-phase 4-wire supply.
2.4.2
Connect the output leads to the desired output terminals which are located on the
top panel. The methods of connection are described in
Section 2.3
. Select the
desired output.
2.4.3
It is advisable to make a preliminary test on the test object, starting at zero voltage,
in order to test the load impedance, before performing the test with regulator set at
higher values. Therefore, ensure the regulator knob is fully anti-clockwise before
switching on.
2.4.4
Connect the supply lead to the mains and move the supply switch to the ON position,
The supply ON lamp should now be illuminated.
2.4.5
Ensure the timer mode switch is in the OFF position. Select the desired ammeter
range.
2.4.6
Depress the ON push-button.
2.4.7
Increase the current by rotating the regulator knob in a clockwise direction until the
desired currents are indicated on the ammeters. Depress the output OFF push-
button.
2.4.8
Connect the test object contacts to the relay contact terminals on the test set,
select timer mode switch:
N/O or N/C contacts
, reset timer if necessary.
2.4.9
Depress the ON push-button and the following occurs:-
a.
Timer will start, current will flow through the test object
b.
Once the test object's contacts have changed state the timer will stop and
the test current will be automatically switched off
c.
2-3 seconds must now elapse before the timer function is active and ready
for a repeat test.
2.4.10 On completion of the test, return regulator to zero and switch off the supply.
Before disconnecting the test object ensure the mains supply switch is in the OFF
position.
2.4.11 It is usual to repeat the above test method several times checking that the times
are consistent. However, it is advisable to allow the relay to cool between tests,
particularly, if large overcurrents are being passed through the relay.
2.4.12 When testing thermal devices or circuit breakers with no auxiliary contacts, the
test method is the same except that the timer control switch is in the "
I
" position.
