Cleaning Disassembled Parts of Accelerator Relay

TM 10-3930-609-35

3-132. Repair and Replacement of Accelerator Relay

d. If contacts on contact arm or on contact bracket

Parts

require replacement, remove nuts from threaded studs

on contacts and withdraw contacts from arm and

a. If contacts are slightly pitted or burned, smooth

bracket.

up surfaces with a file. Do not use emery cloth or

sandpaper. Discoloration on contacts does not affect

e. Remove screws, lockwashers and flatwashers

proper operation and need not be removed if contacts

which secure switch to bracket, and remove switch.

are not pitted or burned. Do not remove more metal

f. Remove self-locking nuts, cup washers and

than necessary to obtain smooth contact surfaces.

springs from studs on armature support; and, withdraw

b. Repair minor thread damage with a tap or

armature from armature support.

thread chaser.

g. Remove screws, lockwashers and flatwashers

c. Replace all cracked or distorted parts.

which secure bracket and armature support to magnet

frame; and, withdraw bracket and armature support.

d. Replace coil if damaged due to overheating or if

resistance measured is not within specified limits.

h. Remove screw and lockwasher from center of

coil core; then, remove coil core, spring washer and coil

from magnet frame.

3-133. Reassembly of Accelerator Relay (fig. 3-24)

a. Mount molded contact support on magnet frame

i. Remove flathead screw and lockwasher to

with flathead screw and lockwasher.

separate magnet frame from molded contact support.

b. Insert coil core through spring washer and

3-130. Cleaning Disassembled Parts of Accelerator

through coil and secure to magnet frame with screw and

lockwasher.

Relay

a. Blow dust from parts with compressed air under

c. Mount bracket and armature support to magnet

moderate pressure.

frame with screws, flatwashers and lockwashers.

b. If additional cleaning is required, wipe parts with

d. Install armature on armature support; then,

cloth moistened with SD.

apply springs, cup washers and self-locking nuts to

studs of armature support.

3-131. Inspecting Parts of Accelerating Relay

e. Mount switch on switch bracket with screws,

a. Inspect all threaded parts and tapped holes for

flatwashers and lockwashers.

stripping or other thread damage.

f. Install contacts on contact bracket and on

b. Inspect bus, contact arm, contact bracket,

contact arm and secure with nuts.

armature support, switch bracket, magnet frame and

g. Place contact arm on stud in armature; then,

armature for distortion or other damage.

place spring and cup washer on stud, and insert

c. Inspect contacts on contact arm and on contact

cotterpin through hole in studs. Spread prongs of

cotterpin just sufficiently to retain cotter-pin.

bracket for wear, pitting or burning.

d. Inspect shunt for fraying and for security of

h. Secure one end of shunt to contact arm with a

screw, flatwasher and lockwasher. Use a screw and

terminations.

lockwasher to secure other end of shunt and bus to

e. Inspect molded contact supports for cracks or

magnet frame.

other damage.

i. Mount stop on molded contact support with

f. Inspect springs for distortion.

screws and lockwashers.

g. Using an ohmmeter or test light, check switch

j. Mount contact bracket on molded contact

for operation as switch plunger is depressed.

support with screw and lockwasher.

h. Using an ohmmeter, check that coil has a

resistance of 46.9 4.7 ohms at 70F. Also inspect coil

for damage due to overheating.

3-45