Overcurrent Protection Control - Hitachi SAMURAI Series Service Manual

2. Control Functions
Control of the cooling cycle

Image diagram of 0 (zero) point adjustment
In superheat control
Thermo OFF

2.2.3 Overcurrent protection control

There is a function to force unload in case that the upper limit of running current of the unit is about to be exceeded. It is
possible to change the setting value of overcurrent protection control from the "Service" menu.

Activation of overcurrent protection
When the running current of the unit reaches the upper limit of running current, the power source capacity load is abated
by means of forced unload operation. (See figure below).
Load down control is continued until reaching 98% of setting value for current limit. Load up control is restricted too
between 95% and 100% of setting value for current limit.
It is also possible to change the setting value for current limit from the settings in "Service".
Setting
value
Setting value x 0.98
Setting value x 0.97
Setting value x 0.95
41
SMGB0097 rev.0 - 07/2015
If the compressor does not stop in 200 hours
Thermo ON
If more than 24 hours have passed since the last 0 (zero) point
adjustment, then 0 (zero) point adjustment is performed during
Thermo OFF.
Load up Forced
limitation unload
Activation of over current protection control
Forced 0 (zero) point adjustment
is performed
Cancel
Compressor
current value
Load up
limitation
2
Restart after 3 minutes
Time