Repair - TM-5-4930-233-140320

TM 5-4930-233-14

TM 4930-14/1

AIR COMPRESSOR ASSEMBLY

5-13. ALTERNATOR - REPAIR - (Cont.)

Repair

CAUTION

Do not immerse alternator assembly in cleaning solvent of any kind. Do not dean

isolation diodes with cleaning solvent. The diodes are coated with a special

corrosion resistant paint. Failure to follow this caution can lead to severe

equipment damage.

WARNING

Cleaning solvent is flammable and toxic to the skin, eyes, and respiratory tract.

Skin, eye, and respiratory tract protection is required.

(1)

Clean parts with a soft bristle brush moistened with tri-ethane.

WARNING

Compressed air used for cleaning or drying can create airborne particles that may

enter the eyes. Pressure shall not exceed 30 psi (207 KPa). Wearing of goggles is

required.

(2)

Dry parts with filtered, low-pressure compressed air or a clean lint-free cloth.

(3)

Inspect brush assembly for excessive wear, replace brush assembly if 3/16 of inch (4.76 mm) or less extends

beyond bottom of holder.

(4)

Check brush assembly spnring tension with suitable spring scale. Spring tension should be 4 to 6 ounces

(112 to 168 grams).

(5)

Test rectifier diode in heat sinks connecting one of multimeter leads to the heat sink and the other multimeter

lead to the diode stem, and note the reading. Then reverse the multimeter lead connections, and note the

reading. If both readings are very low, of if both readings are very high, the diode is defective. A good diode

will give one low reading and one high reading (at least 100 times the low reading).

(6)

Test isolation diode assembly by connecting one of the multimeter test leads to the output terminal stud of

the diode, the other to the exposed metal area on heat sink, and note reading. Then reverse the lead

connections and note reading. If both readings are very low, or if both readings are very high, the diode is

defective.

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