Check diameter of commutator

TM 9- 2920- 224- 34&P

REPAIR OF COMPONENT PARTS - CONTINUED

0009 00

Set lathe to turn armature (5) at 600 to 800 rpm.

d. Make only light cuts, no more than 0.005 inch on each pass, until entire surface of all commutator bars (6) is

involved.

e. Make one final cut at no more than 0.002 inch deep.

Check diameter of commutator (6). The commutator diameter on armature should be within 3.3050 to 3.3190

inch. If less than minimum turned diameter of 3.2200 inch, armature (5) must be replaced.

CAUTION

Use care when undercutting so that no metal is removed

from sides of segments and no mica is left standing

against side of a segment.

NOTE

Mica may be undercut with a machine or hand tools.

g. If turned diameter of commutator (6) is no less than minimum limit, undercut mica 0.052 inch wide to a depth

of 0.025 to 0.032 inch below commutator surface.

h. Start groove in mica with a 3--cornered file.

Undercut mica with a hacksaw blade.

0009 00- 2