Service Manual

11. Electrial checks of main parts
443
SMGB0079 rev.0 - 01/2013
11
11.1.3 Protective function
1 Excessive high or low voltage for inverter
a. Level of detection
• When the voltage of direct current is greater than (A) V abnormalities are detected.
• When the voltage of direct current is smaller than (B) V abnormalities are detected.
Power supply 400V 50Hz 230V 50Hz
(A) 750 440
(B) 350 194
b. Function
When abnormalities are detected the inverter compressor is stopped and transmit the signal code of stoppage
cause to PCB1.
c. Cancellation of protection function.
Transmission for signal code of stoppage cause is cancelled when a stopping order is given or main power source
is cut off.
2 Abnormality of current sensor
a. Level of detection
When current of the inverter compressor decreases lower than 1.5A during the inverter compressor frequency bet-
ween 15Hz and 18Hz an abnormality is detected.
b. Function
When abnormalities are detected the inverter compressor is stopped and transmit the signal code of stoppage
cause to PCB1.
c. Cancellation of Protection Function
Transmission for signal code of stoppage cause is cancelled when a stopping order is issued or main power source
is cut off.
3 Overcurrent protection for inverter
a. Level of detection
When the current detected by current sensor reaches 150% of the rated current overcurrent is detected. (Instanta-
neous overcurrent).When the current detected by current sensor exceeds 105% of the rated current continuously
for 30 seconds or for 3.5 minutes in total during a 10 minutes period overcurrent is detected. (Electric thermal relay).
b. Function
When abnormalities are detected the inverter compressor is stopped and transmit the signal code of stoppage
cause to PCB1.
c. Cancellation of protection function
Transmission for signal code of stoppage cause is cancelled by stopping order is issued or main power source is
cut off.
4 Protection of IPM/DIP-IPM/ISPM
a. Level of detection
When some of the output terminals between “U” and “V” “V” and “W” “W” and “U” of IPM/DIP-IPM/ISPM are short-
circuited an abnormality is detected.When the running current of IPM/DIP-IPM/ISPM reaches (maximum rated
current x 105%) an abnormality is detected.When an internal temperature is measured by internal thermistor of IPM
an abnormality is detected.When the control voltage of IPM/DIP-IPM/ISPM decreases an abnormality is detected.
b. Function
When abnormalities are detected the inverter compressor is stopped and the signal code of stoppage cause is
transmitted to PCB1.
c. Cancellation of protection function
Transmission for signal code of stoppage cause is cancelled when a stopping order is issued or main power source
is cut off.