PHASf ROTATION I t
290B223
Fig.
9
Test Connections for Type CN33P Relay.
in MAl, MA2
&
MA3 until the TRIP contacts just
close. This current should be 2-4 rna. (All three
currents should be the same).
Potent ial coils
should be energized at 125 volts.
C) Open switches A",
B" &
C"
&
reduce voltage on
potential coils until TRIP contacts close. This
potential should be 100 volts or less, line to
neutral.
D)
Close switches A",
B" &
C".
Place switches
A
',
B
'
&
C ' in position 2. Energize potential
coils at 125 volts, phase to neutral.
Adjust the
phasing voltage (voltage across one ohm resis
tors) until CLOSE contacts just close.
This
value should be 0.5-0.8 volts.
Calibration
If the acceptance or routine maintenance check
has shown further adjusting necessary, the following
procedure may be used to recalibrate the relay.
Mechanical
A. Set contacts (See Settings). The moving contacts
10
are adjusted such that the contact springs are
just touching their support.
Just touching is
determined as follows: With t he relay vertical,
as it would be mounted, the moving contact
springs should be touching their respective
supports. Turn the relay counter clockwise until
the moving contact is horizontal. The weight of
the moving TRIP contact should move the con
tact spring away from its support.
Turn the
relay
horizontally
in
the opposite direction
(clockwise) and the CLOSE moving contact spring
should move away from its support.
B.
Adjust the end play of the drum shaft to approx
imately .003 to .010 inches by setting the front
bearing.
C. Check the position of the moving contact as
sembly in relation to the moving element stops.
It should move about an equal distance on either
side of the vertical center line with the station
ary contacts moved back.
If the position is not
correct then loosen the two screws in the counter-
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