Overload Control - Hitachi UTOPIA RAS-4HVRP2E Service Manual

8 Electrical checks of main parts
Inverter
5 Fin temperature increase
a. Level of detection
When the temperature of internal thermistor exceeds more than 80ºC (for 3HP), 90ºC (for 4 to 6HP) an abnorma-
lity 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 sour-
ce is cut off
6 Earth detection
a. Level of detection
When the starting current of the compressor reaches 80% of the overcurrent protection value 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 sour-
ce is cut off.

8.1.6 Overload control

1 Level of detection
When the output current exceeds 105% of the maximum output current an abnormality is detected.
2 Function
An overload signal is issued when output current exceeds 105% of the maximum output current and the frequency
decreases.
For 10 seconds after the output current decreases lower than 88% of the rated current the operation is performed with
the compressor frequency limited to the upper level frequency when the output current decreases lower than 88% of
the rated one.
However if the frequency order is smaller than the maximum value the operation is performed according to the order.
3 Cancellation of protection function
After the operation described in the above item 2. is performed for 10 seconds this control is cancelled.
164 SMGB0136 rev.0 - 07/2021