Hitachi RAS-4-HNCE - Maintenance Notes

11. Electrial checks of main parts
441
SMGB0079 rev.0 - 01/2013
11
Protection function
Applicable model
RAS-(4-6)HNPE RAS-(4-6)HNCE
RAS-(8-12)
HN(P/C)(E)
RAS-(2-2.5)HVNP
RAS-3HVNC
RAS-3HVNPE RAS-(4-6)HVNPE RAS-(4-6)HVNCE
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 400 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 star-
ting. 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 mo-
dule
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 (for 8 to 12HP).
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 n temperature is higher than 80ºC (for 3HP), 90ºC (for 4 to 6HP Premium), 92ºC (for
4 to 6HP Standard) or 100ºC (for 8 to 12HP).
Earth detection The unit is stopped when the compressor is earthing.