8 Electrical checks of main parts
Inverter
SMGB0136 rev.0 - 07/2021
161
8
Protection function
Applicable
model
RAS-3HVRC2 RAS-(4-6)HVNC1E RAS-(4-6)HNC1E
Excessive high
or low voltage
for inverter
Excessive low voltage at a voltage is lower than 194 V DC
Excessive high voltage at a voltage is higher than 400 V DC
Excessive low voltage at a voltage is
lower than 350 V DC
Excessive high voltage at a voltage is
higher than 750 V DC
Abnormality of
current sensor
(0A detection)
1 When the compressor’s operating frequency reaches 15 to 18
Hz after the compressor starts, the effective value of running
current at each phase is 1.5A or less.
2 The wave height value of running current for the phase
positioning is 5A or less before the compressor starts (at the
end of the phase positioning).
Cause of Abnormality: Failure of Current Sensor (on Inverter
PCB),
Failure of IPM, Failure of Compressor, Disconnected Wiring
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%
Detecting current is more than
150% of the rated current
Rated current x
150%
Rated current x
105%
Short-circuit trip of arm *)
Instantaneous overcurrent trip *)
Instantaneous overcurrent trip: it is detected when current valve is over rated current x 150%.
Electronic thermal trip: it is detected when current valve rated current x 105% for over 30 seconds or for over 3
minutes in total within 10 minutes.
NOTE
*) 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.
Short circuit in any of the “U”, “V” or “W” terminals
Running current reaches the maximum rated current.
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).
Earth detection The unit is stopped when the compressor is earthing.
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