GEK-49822
GENERAL
Since all
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
effects of the enclosure will be accurately duplicated during testing. A relay may be
tested without removing it from the panel by using a
test plug.
This plug
makes connections only with the relay and does not disturb any shorting bars in the
case. The
test plug may also be used. Although this test plug allows greater
testing flexibility, it requires CT shorting jumpers 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
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 properly test alternating current relays, it
use a
wave of current and/or voltage.
The purity of the
from harmonics) cannot be expressed as a finite number for any particular
relay; however, any relay using tuned circuits, R-L or RC networks, or saturating
electromagnets (such as time overcurrent relays) is affected by non-sinusoidal
waveforms.
TARGET AND SEAL-IN UNIT
The target and seal-in unit has an operating coil tapped at 0.2 and 2.0 amperes.
When used with trip coils operating on currents ranging from 0.2 to 2.0 amperes at
the minimum control voltage, the target and seal-in tap screw should be set in the 0.2
ampere tap.
When the trip coil current ranges from two to 30 amperes at the minimum
control voltage, the tap screw should be placed in the 2.0 ampere tap.
The seal-in tap screw is the screw holding the right-hand stationary contact of the
seal-in unit. To change the tap setting, first remove the connecting plug. Then take a
screw
the left-hand stationary contact and place it in the desired tap.
Next,
remove the screw
the other
place it back in the left-hand contact. This
procedure is necessary to prevent the right-hand stationary contact from getting out of
adjustment.
Tap screws should
be left in both taps at the same time.
Pickup and Dropout Test
1. Connect relay studs 1 and 2 (see internal connections diagram) to a DC source,
ammeter and load box so that the current can be controlled over a range of 0.1 to 2.0
amperes.
2. Close or jumper the contact(s) that parallel the seal-in unit contact.
3. Increase the current slowly until the seal-in unit picks up. See Table 11.
4. Open the parallel contact circuit of step 2; the seal-in unit should remain in the
picked up position.
5. Decrease the current
until the seal-in unit drops out. See Table 11.
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