Hitachi RAS-10HRNM, Service Manual, Page: 451 / 482

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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 230V, 50Hz 400V, 50Hz
(A) 440 750
(B) 194 350
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 0.5A 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 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.
(Instantaneous 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.
11 Electrical checks of
main parts
443
SMGB0060 rev. 1- 12/2010
11