FUNCTIONING OF EQUIPMENT
Items in parentheses refer to 1973 model only.
and (A1L4) and capacitor A1C3 (A1C4).
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
transistor (A1Q1), resistor (A1R2) and associated
and FO-1). The input shunt trip circuit breaker provides
automatic turn off for high or low input voltages and
manual turn off for the normal operation of the inverter.
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
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).
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
voltmeter A1M4 and the elapsed time indicator A1M5.
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).
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