GEK-45404
12
ELECTRICAL TESTS
Drawout Relays - General
Since all drawout relays in service operate in their cases, it is recommended that they be tested in
their cases or an equivalent steel case. In this way any magnetic effects of the enclosure will be
accurately duplicated during testing. A relay m ay b e tested without removing it from the panel by
using a 12XLA13A test plug. This plug mak es connections only with the relay and does not disturb
any shorting bars in the cas e. Of course, the 12XLA12A test plug may also be used. Although this
test plug allows greater testing fle xib ility, it also requires CT shorting jum pers and the exercise of
greater care since connections are made to both the relay and the external circuitry.
Power Requirements - General
All alternating-current-operated devices are affected by frequency. Since non-sinusoidal waveforms
can be analyzed as a fundamental frequency plus harmonics of the fundamental frequency, it follows
that alternating-current devices (relays) will be affected by the applied waveform.
Therefore, in order to test alternating-current relays properly it is essential to use a sine wave of
current and/or voltage. The purity of the sine wave (i.e. its freedom from harmonics) cannot be
expressed as a finite number for any p a rticular relay; however, and relay u s in g t uned circuits, RL o r
RC networks, or saturating electromagnets (such as time-overcurrent relays) would be especially
affected by non-sinusoidal waveforms.
Similarly, relays requiring DC control power should be tes ted using d irect current and not full-wave
rectified power. Unless the rectified supply is well filtered, many relays will not operate properly
due to the dips in the rectified power. Zener diodes, for example, can turn off during these di p s . As a
general rule the DC source should not contain more than 5% ripple.
Pickup-voltage Test
The pickup voltage should be checked; for the IAV51D, IAV51K, and IAV52K, the pickup voltage
should be checked on more than one tap. See relay n am e pl a t e for value of pickup voltage (closing
volts). Test connections, Fig. 10, are the same as for the time-voltage test except that the timer is not
required.
Time-voltage Test
The time-voltage curves should be checked for one or more settings. Recommended test connections
for this test are shown in Fig. 10.