REPAIR - TM-55-1905-223-24-40157

TM 55-1905-223-24-4

REPAIR

Repair at this level of maintenance is by replacement of: Terminal link (8), voltage regulator (10), reverse polarity

diode (13), reverse rectifier (14), forward rectifier (15), forward polarity diode (16), and varistor (18).

a. Clean Internal Parts and Windings

(1)

Dry dust and dirt may be removed by brushing with bristle brushes followed by vacuum cleaning. Do not

use wire brushes. Vacuum cleaning is an effective and desirable method of removing dry and loose dirt

since it does not scatter dirt.

(2)

Cleaning with a dry cloth is satisfactory when the components are small, the surfaces to be cleaned

accessible and only dry dirt is to be removed.

WARNING

High pressure compressed air tanks, piping systems and air operated

devices possess potential for serious injury to eyes and exposed areas

of skin due to escaping air pressure.

(3)

Blowing out dirt with compressed air is usually effective, particularly when the dirt has collected in places

which cannot be reached with a cloth. Use clean dry air at 30 psi (206 kPa).

b. Check for Faulty Diodes and Varistor.

(1)

With the generator set shut down and cool, and electrical power OFF, check the rectifier diodes. The

rectifier assembly is split into two plates, positive and negative, and the main rotor is connected across

these plates. The positive plate has three positive diodes (semiconductors), and the negative plate has

three negative diodes semiconductors).

CAUTION

Care must be taken to ensure that the correct polarity diodes are fitted to

each respective plate.

(2)

Check the tightness of the diodes to ensure good mechanical and electrical, connection. Tighten the diodes

to 42 in-lb. (4.74 N-m).

(3)

Use a multimeter on the 10,000 ohms scale and check the diode resistance. Disconnect the flexible lead to

each diode and check the forward and reverse resistance.

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