Section III. OPERATION OF THE FILTER UNIT

TM 3-4240-201-13

Section III. OPERATION OF THE FILTER UNIT

disconnects the 24 volt dc power supply. The centrifugal

2-7.

Power Supply

fan operates on 24 volts dc or 30 volts ac. The

centrifugal fan blows the air to the six headpieces

a. Transformer. The transformer, a part of the filter

through the connected hoses.

unit, receives the external power supply. The 115 volt 60

d. 115 Volt 60 Hz ac Power Cable. The 115 volt 60

Hz ac power supply and the 24 volt dc power supply are

Hz ac power cable is 6 feet long. It is a two wire rubber

not part of this filter unit.

covered cable that connects into ordinary housepower

b. General. Make sure that the toggle switch on

outlets by plug connector.

the transformer is in OFF position. Make sure that the

e. 24 Volt dc Power Cable. The 24 volt dc power

power cable that extends from the transformer group is

cable is 3 feet long. It is a two wire rubber covered cable

connected to the air purifier. Then connect the two

that has two clips covered with one black and one red

power cables that extend from the transformer as

plastic cable nipples. Squeezing the cable nipples opens

follows:

the spring-loaded clips. Clamp the black clip over the

(1) to the 115 volt 60 Hz ac power source.

negative terminal and the red clip over the positive

(2) to the 24 volt dc power source. The black

terminal.

cable nipple and clip connect to the negative terminal of

f. Relay. The relay is a double pole double throw

the battery and the red cable nipple and clip connect to

relay that operates when 115 volt 60 cycle ac power is

the positive terminal of the battery.

applied to the armature.

The relay is inside the

transformer case and it operates automatically when the

NOTE

toggle switch is on with 115 volts ac power applied.

Two 12 volt batteries must be connected

g. Air Pitrifier Cable. The air purifier cable is 3 feet

in series as shown in figure 1-1 in order

long. It is a two wire rubber covered cable with a

to get the required 24 volt dc power

electrical connector. The air purifier cable connects the

supply as shown in the wiring diagram

transformer to the air purifier.

(fig. 18).

2-8.

Protective Masks

c. Electrical Operation. When the toggle switch is

turned on and the 115 volt power cable is connected to a

A protective mask will be required for each operator of

power source, current flows through the primary winding

the filter unit. The operator may be referred to as nurse,

of the step down power transformer and through the

orderly, attendant, doctor, medic, aid man, or operator.

armature of the relay, actuating the relay.

The

The operator is responsible for first donning a protective

secondary winding of the step down power transformer is

mask; and then putting headpieces on six patients. A

connected through the toggle switch to the centrifugal

headpiece is not intended to be worn by the operator

fan in the air purifier. If the 115 volt ac power source

(attendant) of the filter unit. The protective mask

ceases for any reason, current ceases to flow through

required for the operator is not part of this filter unit. The

the armature of the relay, and the relay contacts open.

protective mask required for operator protection is the

The 24 volt dc power source is connected to the

authorized field protective mask.

centrifugal fan through a second set of contacts that are

closed in the relay and through the toggle switch. If at

any time during the operation 115 volt ac power

becomes available, the relay connects the secondary

windings of the transformer to the centrifugal fan and

Section IV. OPERATION UNDER UNUSAL CONDITIONS

2-9.

General

2-10.

Details

a. Keep the filter unit free of sand, moisture, mud,

Operation under unusual conditions includes cold

weather, wet weather, mud, seaside, high humidity, and

or any other foreign matter.

high temperatures. Protect the filter unit from exposure

to any of these conditions as much as possible.

2-3