Hitachi RAS-(2-3)HVRN(S)(2), Service Manual

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11 Electrical checks of
main parts
441
SMGB0064 rev.0 - 08/2011
11
Protection function
Applicable model RAS-(4-12)HRNM(2)(E) RAS-(3-6)HVRNM(2)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.