Auxiliary blade release

(6) Auxiliary blade release.

The auxiliary

misalignment of contacts. Do not bump

blade release hook (14, fig. 2-5) should be adjusted to

switch during installation or it may crack or

hold the blade out of the arc chute until a predetermined

break the insulating barriers.

position in the closing operation. Close the switch slowly

(5) Lift and place switch in cabinet on the

with the maintenance handle and note the position of the

mounting angles.

primary blades when the auxiliary blade is released by the

(6)

Line holes of switch base with holes of

hook (10, fig. 2-9). The hook should be adjusted by

mounting angles.

setting the camming screw (8) to release the auxiliary

(7) Insert up through the front hole in the left

blade within the range of 1/2 inch before arcing contacts

side mounting angle a bolt, lockwasher and a plain

touch. After adjustment is made the lock nut (9) should

washer, and thread it hand tight into switch base.

be tightened.

(8) Insert a bolt with lockwasher and plain

(7) Primary contact pressure. The primary

washer up through front hole in right side mounting angle,

place the spacer on top of angle pushing bolt through it

finger pressure has been adjusted at the factory to be 12

and into the tapped hole of switch base. Tighten hand

pounds per contact. This can be measured. with a pull

tight.

scale exerting a pressure against the contact surface.

(9) Insert two bolts and plain washers up

The contact pressure of each finger 15, fig. 2-5) should

through left mounting, one midway, other in rear. Then

be measured individually. Increase or decrease the

place lockwasher and nut on them, tighten hand tight.

contact pressure by loosening or tightening the contact

(10) Install rear right side bolts same manner

bolts (4).

as Step (8).

(8) Arcing finger contact pressure. The arcing

(11) Check switch position for flatness and

finger contact pressure should be 12 pounds. This

alignment, close upper front panel to make sure operating

pressure can again be measured with a spring scale

handle can be inserted and used to operate switch. If

against the contact surface. Loosen or tighten the contact

switch is not at proper height, raise mounting angle to

bolts (7, fig. 2-8) as necessary.

next hole up in cabinet side or spacer may have to be

(9) Primary blade hinge pressure. The correct

used.

hinge pressure is essential for proper operation of the

CAUTION

switch. The hinge pressure is difficult to measure. A

required torque to move the primary blades can be easily

If spacers are used in mounting switch,

measured and substituted. The break away torque of the

make sure switch is mounted flat and is

hinge (the torque required to start the blades moving)

not distorted. If it is twisted and

should be between 60 to 90 inch-pounds. This can be

distorted it will not operate because of

measured by pulling at the buffer stop or spacer (1, fig. 2-

misalignment.

6) on the primary blade. Use a spring scale without the

(12) When switch is mounted in correct

primary contacts, arcing contacts and auxiliary block

position and flat, tighten all five mounting bolts. See table

contacts engaged. The scale reading should be 51/2 to

1-1 for correct torque values.

81/a pounds. If adjustment is necessary, remove cotter

(13) Fasten the ends of the narrow insulating

pin from either side of hinge pin (16, fig. 2- 5 1. Tighten

barrier across the bottom front of switch to the mounting

or loosen the nut as required. Move the nut in increments

angles.

of one sixth of a turn. This assures line-up for the cotter

d. Test. A standard 60 cycle high potential test at

pin replacement in hole and slot in the nut.

14,000 volts RMS will normally indicate whether the

c. Mounting Load Break Switch.

device is satisfactory for service.

(1) Open upper and lower hinged front panels

WARNING

of high voltage section.

Before applying a high-potential test make

(2) Remove upper and lower rear panels.

certain that the switch is disconnected

(3) Remove horizontal barriers and hardware

from the source and load.

that fit around primary connectors of switch.

(1) With the switch contacts in the fully

(4) Inspect switch mounting angles in cabinet

opened position, apply the high potential to each terminal

for level from front to rear and from one side to the other.

individually for one minute with all the other terminals and

When mountings are level and square make sure they are

the frame grounded.

tight.

(2) After high potential tests are made all

CAUTION

organic insulating material should be inspected for visible

Switch must be mounted in the housing,

leakage current paths. Necessary action must be taken to

supported at both front and rear. Care

replace insulation that may have been affected by

must be taken not to distort the frame by

moisture absorption.

mounting on unflat or out of square

surfaces

twisting

will

cause

2-9