Clutch Adjustment; Trip Unit (G2); Directional Unit (Gd) - GE CLPG12C Instructions Manual

GEI-83910
TRIP UNIT (G2)
Pickup: Connect the taps in the G2 tap block so that the desired setting will be
within the selected tap range. Should the desired setting be such that either tap
range would be adequate, it is recommended that the lower tap range be used on two-
terminal lines and the higher tap range be used on three-terminal lines. Using the
test connections shown in Figure 9, apply the desired level of current to the relay
and set pickup by means of the control-spring adjustment, as previously described
for the G1 unit.
G2 Unit Rebound Test:
Connect the relay as shown in Figure 7, and check that the G2-unit contact
wi 11 not rebound on the removal of an external fault. The test connections show
the TB unit of the NAA22A being used for this test but if an instantaneous dropout
relay is available it may be substituted. The use of the TB unit will result in
loss of instantaneous reclosure in the carri er-current scheme, and the TB unit
contact in circuit 15-16 must be shorted so that protection is still provided.
The following test procedure should be followed.
1. Close the G2 unit manually to check that the lamp will light.
2. Manually close the TB unit and apply maximum expected through-fault
current to the G2 unit.
3. Remove the current and check that the lamp does not light.
CAUTION:
It is advisable to practice this sequence, so that the tester will be
able to operate it correctly with a high-current impulse short enough
to avoid overheating the unit.
If the G2 unit fails this test, check the wipe and gap of the G2 barrel contacts,
and also the clutch slip adjustment.
CLUTCH ADJUSTMENT
Using the test connections shown in Figure 9 and the appropriate value shown
in Table II, check the clutch adjustment as previously described for the Gl unit.
DIRECTIONAL UNIT (GO)
Current-Polarized Pickup: Using the test connections shown in Figure 9, apply
the desired level of current to the relay and set pickup by means of the control-
spring adjustment, as previously described for the G1 unit. The product pickup
thus obtained will be the square of the current app 1 i ed to the relay. Thus,
if
a
product pickup of 0.25 ampere is desired, 0.5 ampere should be applied to the
relay.
Potential-Polarized Pickup: Using the test connections shown in Figure 12, the
GO unit can be set for potential polarization. When setting pickup for potential
polarization, it is recommended that a voltage (Vp) of 5 to 30 volts be used. Five
volts is the minimum value encountered in ground relaying, while above 30 volts the
current is small and difficult to measure.
Clutch Adjustment: Using the test connections shown in Figure 9 and the
appropriate value from Table II, the clutch may now be set as previously described
for the G1 unit.
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