Chapter 5. FUNCTIONING OF EQUIPMENT

TM 11-6130-377-14

CHAPTER 5

FUNCTIONING OF EQUIPMENT

NOTE

Items in parentheses refer to 1973 model only.

and (A1L4) and capacitor A1C3 (A1C4).

5-1. General

(5) Output Circuit Breaker and Relay (fig. 5-1E

This section describes the major functions of the inverter

and FO-1). The output of the ferroresonant filter system

at detailed schematic and block diagram levels. In

drives through the output circuit breaker A1CB2. The

addition, the functional circuits of inverter drive circuit

circuit breaker is used as an ON/OFF feature. (In the

board A1A2 are covered to explain the operating

1973 model, relay A1K3 operates during the soft start

relationships between functional elements.

feature that holds back ac output at terminals X1 and X2

5-2. System Description of Inverter

of A1TB2. The relay will be deenergized at start.)

a. The major functions of the various circuits of the

(6) 12 Volt Shunt Regulator, 1978 model only

inverter are described in the following subparagraphs and

(fig. 5-1F and FO-1). The shunt regulator provides a

are to be used in conjunction with figures 5-1 and FO-1.

regulated 12 volts dc to the inverter drive circuit board

from the 110-volt dc input. This circuit consists of

(1) Input Shunt Trip Circuit Breaker (fig. 5-1A

transistor (A1Q1), resistor (A1R2) and associated

and FO-1). The input shunt trip circuit breaker provides

circuitry.

automatic turn off for high or low input voltages and

manual turn off for the normal operation of the inverter.

(7) Inverter Drive Circuit Board (fig. 5-1G and

The circuit consists of DC circuit breaker A1CB1 (relay

FO-1). The inverter drive and its control circuitry is

A1K1) and associated circuitry.

located in inverter drive circuit board A1A2 (para 5-3).

The circuit board has the oscillator, the drive for the

(2) Input Filter and Soft Start (fig. 5-1B and FO-

SCR's, the control signals for soft start, and the sensor

1). The input filter attenuates noise so that the inverter

circuits which drive the input circuit breaker.

does not induce noise back into the DC input line. The

input filter consists of choke A1L1 capacitors A1C1 and

(8) Metering (fig. 51H and FO-1).

The

A1C2, and associated circuitry. (The soft start circuit

metering which is throughout the system consists of the

consists of SCR A1Q2, resistor A1R6, and associated

input DC voltmeter A1M1, the input DC ammeter A1M2,

drive circuitry resistors A1R4, A1R5 and capacitors A1C5

the output AC current meter A1M3, the output AC

and A1C6.)

voltmeter A1M4 and the elapsed time indicator A1M5.

(3) SCR Inverter (fig. 5-1C and FO-1). The

NOTE

silicone controlled rectifier (SCR) inverter drives the

Reference designation prefix A1 is

ferroresonant transformer and filter system. The SCR

deleted in the following discussion:

inverter consists of SCR A1Q1 (A1Q3), A1Q2 (A1Q4),

diodes A1CR4 (A1CR6), A1CR5 (A1CR7), capacitor

b. A detailed functional description of the operation,

A1C2 (A1C3), and inductors A1L2 and A1L3 (A1L5).

circuits and components of the inverter are described in

the following paragraphs (fig. FO-1).

(4) Ferroresonant Transformer and Filter (fig.

5-1D and FO-1). The ferroresonant transformer and filter

(1) When DC input power is connected to the

provide a 120-volt, 60-Hz sine wave output. This circuitry

system, DC VOLTAGE meter M1 indicates that input

consists of transformer A1T1, chokes A1L4 (A1L3), A1L5

voltage and power are being applied to

Change 1

5-1