Hitachi RAS-10HRNM, Service Manual, Page: 443 / 482

Protection function
Applicable model RAS-(4-12)HRNM(1)(E) RAS-(3-6)HVRNM(1)E
Excessive high or low voltage for inverter
Excessive low voltage at a voltage is lower than
350 V DC
Excessive high voltage at a voltage is higher than
750 V DC
Excessive low voltage at a voltage is lower than
194 V DC
Excessive high voltage at a voltage is higher than
420 V DC
Abnormality of current sensor (0A detection)
Stoppage at a current of compressor smaller than
1.5A.
When the frequency is 15 to 18Hz after starting.
Cause of abnormality:
Failure of current sensor
Failure of IPM/DIP-IPM/ ISPM
Failure of compressor / fan motor
Disconnected wiring
—
Overcurrent protection for inverter
Time
Detecting current is more than
150% of the rated current.
Rated
current
x 150%
Rated
current
x 105%
1
Short-circuit trip of arm *)
2
Instantaneous overcurrent trip *)
3
Instantaneous overcurrent trip
4
Electronic thermal trip
*) Internal protection IPM
Condition is maintained longer than 30 seconds or accumulated longer than 3 minutes during 10 minutes
sampling time.
Protection of transistor module
IPM has four protection function for self-protection.
1
Some of the output terminals between "U" and "V", "V" and "W", "W" and "U" has a short-circuit.
2
Running current reaches the maximum rated current.
3
Abnormal temperature is measured by internal thermistor.
4
Control voltage decreases abnormally.
Overload control
Overload control as a current greater than (rated current X105%).
Overload control release at a current smaller than (rated current X 88%).
Fin temperature increase The unit is stopped when the fin temperature is higher than 100ºC
Earth detection The unit is stopped when the compressor is earthing.
11 Electrical checks of
main parts
435
SMGB0060 rev. 1- 12/2010
11