Emergency/Test Operation; Inverter System Control - Mitsubishi Electric MSC-CA20VB Service Technical Manual

6-21. EMERGENCY / TEST OPERATION
In case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the front of the indoor
unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of remote con-
troller run down. The unit will start and OPERATION INDICATOR lamp will light.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan speed runs at
High speed and the system is in continuous operation. (The thermostat is ON.)
After 30 minutes of test run operation, the system shifts to EMERGENCY COOL / HEAT MODE with a set temperature of
24°C.
The fan speed shifts to Med. speed.
The coil frost prevention works even in emergency operation, and defrosting too.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO (
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter, normal operation will start.
NOTE : Do not press EMERGENCY OPERATION switch during normal operation.

6-22. INVERTER SYSTEM CONTROL

6-22-1. Inverter main power supply circuit
NOISE
POWER
N/F
SUPPLY
Function of main parts
SYMBOL
IPM INTELLIGENT POWER MODULE
CB1~3
SMOOTHING CAPACITOR
CT1~2
CURRENT TRANSFORMER
CT61 CURRENT TRANSFORMER
L
REACTOR
PFC POWER FACTOR CONTROLLER
R64A, R64B
CURRENT-LIMITING RESISTOR
X64
RELAY
EMERGENCY
OPERATION switch
FILTER P. C. BOARD
R64A/R64B
X64
CT61
NAME
• The following indication applies
regardless of the shape of lamp.
OPERATION INDICATOR lamp
Press once
Press again
Press once again
POWER BOARD
L
PFC
It supplies three-phase AC power to compressor.
It stabilizes the DC voltage.
It measures the current of the compressor motor.
It measures the current of the main power supply circuit.
It rectifies AC, controls its voltage and improves the power factor of
power supply.
It restricts rush current with the resistance.
It short-circuits the resistance which restricts rush current during the
compressor operates.
95
) mode.
<Cool>
<Heat>
<Stop>
V
MC
CT1
U
U
+CB1
CB2
CB3
IPM
V
CT2
W
FUNCTION
Lighted
Not lighted
W