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41-251.21C
6.6.1
Adjustment and Calibration
Initially adjust unit on the pedestal so that armature
fingers do not touch the yoke in the reset position
(viewed from top of switch between cover and
frame). This can be done by loosening the mounting
screw in the molded pedestal and moving the ICS in
the downward position.
a. Contact Wipe
Adjust the stationary contact so that both station-
ary contacts make with the moving contacts
simultaneously and wipe 1/64" to 3/64" when the
armature is against the core.
b. Target
Manually raise the moving contacts and check to
see that the target drops at the same time as the
contacts make or up to 1/16" ahead. The cover
may be removed and the tab holding the target
reformed slightly, if necessary. However, care
should be exercised so that the target will not
drop with a slight jar.
c. Pickup
The unit should pickup at 98% rating and not
pickup at 85% of rating. If necessary, the cover
leaf springs may be adjusted. To lower the
pickup current use a tweezer or similar tool and
squeeze each leaf spring approximately equal by
applying the tweezer between the leaf spring and
the front surface of the cover at the bottom of the
lower window.
If the pickup is low, the front cover must be
removed and the leaf spring bent outward
equally.
6.7
DIRECTIONAL UNIT (D)
The upper pin bearing should be screwed down until
there is approximately .025" clearance between it
and the top of shaft bearing. The upper pin bearing
should then be securely locked in position with the
locknut. The lower bearing position is fixed and can-
not be adjusted.
The contact gap adjustment for the directional unit is
made as follows:
6
With the moving contact in the normally opened posi-
tion, i.e., against the right stop on bridge, screw in the
stationary contact until both contacts just close as
indicated by a neon lamp in the contact circuit. Then,
screw the stationary contact away from the moving
contacts 3/4 of a turn.
The clamp holding the stationary contact housing
need not be loosened for the adjustment since the
clamp utilizes a spring-type action in holding the sta-
tionary contact in position.
The set screw in the stationary contacts have been
factory adjusted for optimum follow and thus adjust-
ment should not be disturbed.
The moving contact assembly has been factory
adjusted for low contact bounce performance and
should not be changed.
6.8
MAXIMUM TORQUE ADJUSTMENT
Apply rated voltage to terminals 6 and 7, and 4
amperes to terminals 8 and 9, making sure the polar-
ities are correct. With the voltage and current in
phase, the contacts should close. Now adjust the
angle between current and voltage to 120° (current
leading the voltage). Adjust the resistor to just close
the contacts. Contacts should open when the angle
between current and voltage is 120° +1° leading.
The sensitivity adjustment is made by varying the
tension of the spiral spring attached to the moving
element assembly. The spring is adjusted by placing
a screwdriver or similar tool into one of the notches
located on the periphery of the spring adjuster and
rotating it. The spring adjuster is located on the
underside of the bridge and is held in place by a
spring type clamp that does not have to be loosened
prior to making the necessary adjustments.
The spring is to be adjusted such that the contacts
will close as indicated by a neon lamp in the contact
circuit when energized with the required current and
voltage as shown in Table 1, page 4. This table indi-
cates that the spring can be adjusted when the
phase angle relationship between the operating cir-
cuit and the polarizing circuit is at the maximum
torque angle or when the circuit relationship has the
Type CRN-1
Reverse Power Relay
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