I.L. 41-490H
23
b. Use the No. 4 test connection and repeat the pro-
cedure above for checking the T
B C
compensator.
15.2 Spring Restraint
a. Use test No. 1 connections except reverse the
voltage phase sequence by interchanging the
Brush connections so that Brush No. 1 is connect-
ed to 3F and Brush No. 2 is connected to 1F.
b. Adjust the voltage V
1F2F
and V
2F3F
for 3.5 volts
each with Brush No. 2 and Brush No. 1 respec-
tively. Position the moving-contact spring adjuster
so that the contact just floats and then return the
circuit connections to normal with Brush No. 1 to
1F and Brush No. 2 to 3F. De-energize the relay.
Spring should reset the contacts.
15.3 Contact Adjustment
The procedure for contact adjustment for the
phase-to-phase unit is identical to that described for
three-phase unit.
15.4 Impedance Check
Using the connections for Test Nos. 5, 6, and 7, set
the phase-shifter so that the current lags voltage by
θ
m
. The current required to trip the phase-to-phase
unit should be within the limits specified for each of
the voltages. Note that for the phase-to-phase unit
t h e i m p e d a n c e m e a s u r e d b y t h e r e l a y i s
where V
L-L
is phase-to-phase fault
voltage and I
L
is phase current.
The current required to close contacts of the top unit
should be:
∆
For current limits when
θ
m maximum torque angle is not
75˚, multiply the values above by
where
β
= new
maximum torque angle for which the relay was calibrated.
For test voltages to be of correct sequence and val-
ues, use the following equation:
(13)
15.5 Indicating Contactor Switch (ICS)
Close the main relay contacts and pass-sufficient dc
current through the trip circuit to close the contacts
of the ICS. The current should not be greater than
the particular ICS tap setting being used for the
0.2–2.0 ampere ICS. The operation indicator target
should drop freely.
The contact gap should be approximately 0.047" for
the 0.2/2.0 ampere unit between the bridging moving
contact and the adjustable stationary contacts. The
bridging moving contact should touch both station-
ary contacts simultaneously.
16. COMPENSATOR CHECK
Accuracy of the mutual impedance Z
C
of the com-
pensators is set within very close tolerances at the
factory and should not change under normal condi-
tions. The mutual impedance of the compensators
can be checked with accurate instruments by the
procedure outlined below.
a. Set T, T
A
, T
B
, T
B
, and T
C
on the 1.23 tap for
.2
-
4.5 range
5.80 tap for
.75
- 21.2 range
10.0 tap for
1.3
- 36.6 range
b. Disconnect the “L” leads of sections M, M
A
, and
M
C
and the red-marked leads of R
3
, R
2A
, and R
2C
(with resistor loading removed
θ
= 90˚.
c. Connect terminals 12 to 14, 15 to 17, 16 to 18 and
pass 10 amperes ac current in terminal 19 and out
of terminal 13.
d. Measure the compensator voltage V
C
with a high
resistance voltmeter (5,000 ohm/volt) as tabulat-
ed below. Refer to Figure 1 for the location of R
3
,
R
2A
AND R
2C
.
Relay Range
.2 - 4.5
.75 - 21.2
1.3 - 36.6
V
fault
= V
1F-2F
(Volts)
30
30
30
∆
Trip Current (amps) 13.3 - 14.7 2.85 - 3.15 1.63 - 1.80
Phase-shifter
Set at current lagging
V
1F-2F
(
θ
m
)
75˚
75˚
75˚
Z
R
V
L
L
–
2
I
L
---------------
=
75
sin
β
sin
---------------
Measure V
C
Between
Voltmeter Reading
Lead
and Fixed
End of
V
1
1
F
–
V
2
2
F
–
V
in
V
fault
–
2
-------------------------------
=
=
