Replacement of Armature Shaft.

(12) Remove pole shoe from each field coil,

(a) Insert the shaft in the armature as

then remove coil assembly.

far as possible, using hand pressure only.

Note. Record sequence of disassembly to

(b) With assembly in vertical position,

place a 3 inch long, 1 1/2 inch inside diameter, 2 inch

insure proper reassembly.

outside diameter pipe against the commutator sleeve.

(13) Disassemble and remove terminal studs if

damaged.

f. Replacement of Armature Shaft.

pipe against the bearing shoulder (drive end), apply

vertical pressure until the shaft bottoms completely

Note. If armature or armature shaft is

against the core support.

damaged. perform the following:

g. Cleaning and Inspection. Clean and inspect

(1) Disassembly.

pump motor as follows:

Caution: Insure that top end of pipe

Warning: Use an approved cleaning

makes complete contact with the core from above

solvent in a well ventilated area when cleaning parts.

the shaft, but under the core rivets.

Caution: Armature and armature field

(a) Place drive end of armature shaft in

windings must be cleaned using a clean cloth

a pipe approximately 2 inches inside diameter and

approximately 15 inches long. (fig. 3-38.)

dampened in solvent. Do not soak, dip, or saturate

armature or field windings.

(1) Using a clean cloth dampened in solvent,

clean armature and field windings and allow to dry

thoroughly.

(2) Clean all other parts in solvent and allow

to dry thoroughly.

(3) Inspect all parts for wear, broken windings,

and damage.

h. Test.

Caution: Whenever connections have

to be soldered, a resin flux must be used. Acid flux

must never be used on electrical connections.

(1) Check armature for shorts by placing it on

a "growler" and with a steel strip or a hack saw blade

held on armature core, rotate armature.

If blade

vibrates, armature is shorted in area of the core below

the vibrating blade. Copper or brush dust in slots

between commutator bars sometimes cause shorts

which can be eliminated by cleaning out slots. Shorts at

crossovers of coils at core end can often be eliminated

by bending wire slightly and re-insulating exposed bare

wire. If short cannot be eliminated, armature must be

replaced.

(2) To test armature for grounds, place one

probe of test lamp on armature core or shaft and place

other probe on each commutator bar in turn. If lamp

lights, armature is grounded and must be replaced.

(3) To test for grounded fields, place one

probe of test lamp on field frame and other probe on field

terminal. If lamp lights, field coils are grounded and

Figure 3-38. Armature shaft pipes.

must be replaced, if ground cannot be located and

(b) a second pipe of 11/4 inches inside

required.

diameter, 1 1/2 inches (maximum) outside diameter, and

i. Commutator Repair.

Carefully inspect the

approximately 4 inches long against the bearing shoulder

commutator. If burned, rough, or out-of-round, it must be

on the commutator end of the shaft.

cut down and the mica undercut. Minimum diameter for

undercutting is 3 inches.

(commutator end) and press the shaft from the arm

attire.

(2) Reassembly.

3-56