THEORY OF OPERATION - TM-9-2920-224-34-P0021

TM 9- 2920- 224- 34&P

THEORY OF OPERATION

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THIS WORK PACKAGE COVERS:

Theory of Operation and Equipment Data

GENERATOR OPERATION

a. Mounting Holes. The generator is mounted to mounting pad on the engine by six studs which correspond to

six keyhole--type mounting holes (14) in flanged end of generator housing.

b. Generator drive shaft (15) is spline coupled to the engine drive and transmits engine drive torque to both ends

of hollow armature shaft. Connection between drive shaft and armature shaft at drive end is not rigid but

through friction damper mechanism (16) on the drive shaft. Connection between drive shaft and armature

shaft at commutator end is made quite rigid by tapered splines drawn together.

1) Friction damper mechanism (16) is adjusted to allow limited slippage at about 20 lb--ft. Input torques

which exceed setting of damper mechanism use the length of drive shaft (15) as a torsion bar. Torsion

spring action absorbs shocks (sharp peaks in drive torque) which could damage generator.

2) Damper mechanism (16) also permits at least 0.010 inch displacement between axis of generator input

spline and axis of male spline on armature (19).

Stator assembly

11.

Commutator end bearing

Pole shoe

12.

Brush cover band assy

Filter assembly

13.

Interpole coil

Ground lead

14.

Keyhole--type mounting hole

Brush spring

15.

Drive shaft assembly

Brush assembly

16.

Damper mechanism

Brush holder

17.

Air--outlet grille

End bell

18.

Drive end bearing

Fan cover

19.

Armature

10.

Cooling fan

20.

Field coil

Figure 1--2. Sectional View of Typical Generator Assembly.

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