Hitachi UTOPIA RAS-4HVRP2E Service Manual page 165

8 Electrical checks of main parts
Inverter
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
between 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 sour-
ce is cut off.
3 Overcurrent protection for inverter
a. Level of detection
Š When the current detected by current sensor reaches 150% of the rated current overcurrent is detected. (Ins-
tantaneous overcurrent).
Š 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
Š When some of the output terminals "U", "V" or "W" of IPM/DIP-IPM/ISPM are short-circuited an abnormality is
detected.
Š When the running current of IPM/DIP-IPM/ISPM reaches (maximum rated current x 105%) an abnormality is
detected.
Š 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 sour-
ce is cut off.
163 SMGB0136 rev.0 - 07/2021
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