Figure 4-41.2. Alternator testing. (Sheet 2 of 8)

Custom Search

Figure 4-41.1. Alternator testing.(Sheet 1 of 8)

TM-55-1905-217-12 Landing Craft Mechanized; Steel; DED; Overait Length 74 Feet Mod 1 Marl VIII Navy Design LCM-8 Hull Numbers 8500 and 8580 thru 8618 Manual

Figure 4-41.3. Alternator testing. (Sheet 3 of 8)

TM 55-1905-217-12

low when testing the alternator system.

(4) The voltage regulator used on hull

numbers 8540 thru 8560 and 8580 thru 8618 can be

adjusted by two methods to suit operating conditions.

CAUTION

Disconnect battery negative lead prior to removing or

installing the voltage regulator.

A step adjustment can be made by removing the voltage

regulator and using the metal strap provided on the

underside of the regulator. Placing the strap between

the center terminal and "LO" terminal, the voltage will be

decreased by 0.6 volt. A fine adjustment of the voltage

can be made by the following procedure:

Figure 4-41.2. Alternator testing. (Sheet 2 of 8)

(a) Engine not running.

(b) Connect voltmeter across battery

CAUTION

terminals.

Do not disconnect either alternator output lead while the

alternator is operating.

scale) between the positive terminal of the starter

solenoid and the positive output terminal of the

CAUTION

alternator.

Do not disconnect any battery cable connection while the

(d) Start engine and operate at 1000

alternator is operating.

rpm.

(e) Apply accessory load (or adjust

CAUTION

carbon pile) until ammeter reads 10.0 to 15.0 amperes.

Do not ground alternator field terminal.

(f) Allow electrical system to stabilize

(voltmeter stops changing).

CAUTION

(g) Remove the screw in the regulator

Disconnect negative battery cable prior to removing or

cover to gain access to the rheostat. Using a No. 0

installing alternator or regulator.

Phillip screwdriver, turn 1 clockwise to increase voltage

or counterclockwise to decrease the voltage until the

NOTE

voltmeter indicates the desired reading.

When doing alternator systems checks, ensure that

landing craft battery is in good condition and fully

CAUTION

charged.

Do not force rheostat beyond stops.

(2) Volt-ammeter resistance testing unit with

(h) Replace screw in regulator cover

following meter scales:

when adjustment is completed.

DC voltmeter

0-40 volts

d. Alternator Removal (fig. 4-42 and fig. 4-43) for

DC ammeter

0-10 amps, 0-100 amps

Hull Numbers 8540 thru 8560 and 8580 thru 8618.

Series Resistor

1/4 ohm

(1) Remove the alternator cover.

Field rheostat

0-50 ohm/65 watt

(2) Remove and tag electrical leads.

(3) Remove -adjustment strap bolt and move

Carbon pile

alternator as necessary to remove belt.

Ohmmeter

(4) Remove mounting bolt and remove

DC test lamp, 12 or 24 volts

alternator.

Battery hydrometer

Jumper leads 2, 4, 6, 10 feet in length with alligator clips

(3) Figures 4-41.5 through 4-41.8 provides

test instructions and test schematics to fol-

4-45