Mitsubishi Electric MS-A WA Service Technical Manual page 13

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NOISE
POWER
FILTER
SUPPLY
CIRCUIT
Function of main parts
NAME
INTELLIGENT POWER MODULE
SMOOTHING CAPACITOR
CURRENT TRANSFORMER
REACTOR
POWER FACTOR CORRECTION MODULE
RESISTOR
RELAY
2-7-2. Outline of main power supply circuit
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1. At the start of operation
Main power supply circuit is formed when RELAY is turned ON at COMPRESSOR startup.
To prevent rush current from running into the circuit when power supply is turned ON,
RESISTOR is placed in sub circuit.
2. At normal operation
When AC runs into POWER P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT.
After noise is eliminated from AC, it is rectifi ed to DC by DIODE MODULE 1.
DC voltage, to which AC has been rectifi ed by process
TELLIGENT POWER MODULE.
DC voltage, which has been stabilized in process
supplied to COMPRESSOR.
CURRENT TRANSFORMER, which is placed in the power supply circuit to COMPRESSOR, is used to measure the value
of phase current and locate the polar direction of rotor with algorithm. PWM (Pulse width modulation) controls impressed
voltage and frequency with those pieces of information.
REACTOR
RESISTOR
RELAY
POWER FACTOR
CORRECTION
MODULE
It supplies 3-phase AC power to compressor.
It stabilizes the DC voltage and supplies it to INTELLIGENT POWER MODULE.
It measures the current of the compressor motor.
It rectifi es AC, controls its voltage and improves the power factor of power supply.
It absorbs the rush current not to run into the main power supply circuit when the
electricity turns ON.
It keeps the RESISTOR, which restricts rush current, short-circuited while the
compressor is operating.
, is converted to 3-phase AC by INTELLIGENT POWER MODULE and
P
+
SMOOTHING
CAPACITOR
N
INTELLIGENT
POWER MODULE
FUNCTION
, is stabilized by SMOOTHING CAPACITOR and supplied to IN-
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CURRENT
TRANSFORMER
U
U
MS
V
3~
V
W
W
COMPRESSOR