Maintenance - TM-3-4240-201-130033

TM 3-4240-201-13

the armature of the relay (5). When the armature of the

of transformer case. Installation is the reverse of

relay is deenergized, the relay mechanically switches to

removal procedure.

(3) 90 plug connector. When removing the

close a second set of contacts. The 24 volt dc power

source is connected through the second set of contacts

electrical plug connector assembly (1) on the air purifier

in the relay, through the toggle switch, and through the

power cable (18), unscrew the electrical connector cable

air purifier cable to operate the electric motor in the

clamp (3) from the electrical plug connector (1). Slide

centrifugal fan assembly. If at any time during operation,

sleeving (2) back (or up wire) from the connector. Cut

115 volt ac power becomes available, the current flows

the wire. Prepare the end of the power cable (18) for a

through the primary winding of the transformer and the

new electrical plug connector (1). Solder one wire to

armature of the relay. Actuating the armature of the

connector terminal. Bind the ground wire (24) (stripped

relay disconnects the 24 volt dc power source and

of insulation) back along cable so that it comes into

connects the 30 volt ac power from the step down power

contact with the 90 housing of connector (25). This acts

transformer.

as a ground. Push the sleeving (2) back into place and

reassemble the connector. Tighten the two screws so

that the clamp firmly grips the cable (18).

5-5.

Maintenance

(4) Plug connector.

Remove the plug

connector (17) from the 115 volt ac power cable by

a. Transformer Case. Determine whether the case

removing the screws which fasten the wires to the

or cover is damaged. Replace if necessary. Check all

terminals of the connector; then pull the plug connector

circuits within the transformer case for continuity using a

from the power cable. Strip insulation from power cable.

voltmeter or ohmmeter. Replace defective parts and

Fasten wires to each terminal by wrapping the lead

check for continuity.

under the screw. Tighten screw.

b. Power Cables. Disconnect the ac and dc power

c. Relay. Inspect the contacts and clean them if

sources.

Inspect the power cables for damaged

necessary. Tag and disconnect or unsolder the electrical

insulation, connectors, electrical connector cable clamp,

wires from the relay (5) terminals. Remove machine

and battery electrical clips. If inspection reveals damage,

screws (4) and remove the relay from the transformer

disassemble or remove ((1) through (4) below).

case.

Assembly or installation procedure is the reverse of

d. Toggle Switch.

Tag and disconnect the

removal of disassembly procedure.

electrical wires (13) from the toggle switch (14). Remove

(1) Replacing battery electrical clips and

machine screws (15) and remove toggle switch (14) from

cable nipples. The cable nipples (19, fig. 5-4) are made

transformer case (16). Fasten the toggle switch inside

of plastic and are used to insulate the battery electrical

the transformer case using the machine screws. Fasten

clips (20). Slide the cable nipples back along the battery

the insulated electrical wiring (13) to the terminals on the

power cable (18) far enough to expose the screw

toggle switch (14).

terminals on the battery electrical clips. Loosen the

e. Transformer. Tag and disconnect the insulated

screws and disconnect the clips from the cable.

electrical wires from the transformer (10). Remove

Examine the red and black colored plastic cable nipples

machine screws (6), flat washers (7), lockwashers (8),

(19) at this time.

If the cable nipples require

and nuts (9).

Remove the transformer from the

replacement, do it while the electrical clips are

transformer case (16). Fasten the transformer in the

disconnected. Install a cable nipple by pushing a wire

case using the four screws (6), flat washers (7),

from the battery power cable through the nipple. Install

lockwashers (8), and nuts (9). When connecting wires,

battery electrical clips by reconnecting the wires to the

make sure that the primary winding of the transformer is

clips. Slide the nipples over the battery clips leaving only

connected to 115 volts 60 Hz ac wiring (fig. 1-6). Make

the jaws exposed.

sure that the secondary winding of the transformer is

(2) Power cables. Remove the transformer

connected to 30 volts ac wiring as shown in figure 1-6.

cover (11, fig. 5-4). To disconnect one or all three

power cables (18) from the transformer case (16),

unscrew the electrical conduit bushing (22), loosen the

electrical box connector (23), and disconnect the wires

of the cables from their points of connection inside the

transformer TM 3-4240-201-13 case. Pull wiring clear

5-5