7-2-2. Current Control
The operating current may rise as a result of causes including increasing heating or cooling loads or decreases in power
voltage. In these cases, the operating frequency is automatically reduced, or operation is stopped, in order to control
the operating current so that it is (20 A) or less.
The operating frequency is reduced automatically, or operation is stopped, in order to control the operating
current so that it is at or below the values shown in the table below.
(20A)
HEAT
Power breakers and fuses will not be tripped.
Operation can continue during this period with somewhat reduced heating or cooling capacity.
Operation at normal capacity is restored when the cause of the current rise is eliminated.
Description of function
•
•
•
Example of operation for heating
Current(A)
Frequency (Hz)
Trip
Hz reduction
Hz increase
prohibit
Hz reduction
Hz increase prohibit
Hz reduction
Hz increase prohibit
(16)
(15.6)
0
(30)
Example of operation during cooling
Frequency
Frequency
Current
Stops operation
Approx.3 minutes
Power Point C
Point B
Point A
(20A)
(17A)
(16.6A)
Target
frequency
Operates at the target frequency at Point A and below.
Stops increases to the frequency between Points A and B.
Reduces the frequency by 1 Hz per 0.5 seconds when Point B is exceeded.
Stops operation, and restarts it appoximately 3 minutes later, if Point C is exceeded.
(May operate when sudden voltage fluctuations occur. Indicates trouble.)
•
•
•
•
As a result:
(1) Automatic frequency control
The operating frequency upper limits shown in the figure below are established for frequency reduction and
increase-prohibit.
(2) Current control
NOTE
During defrost operation, the COOL current setting value is used.
COOL
(20.0)
(20.0)
(17.0)
(17.0)
(16.6)
Point C (peak cut trip)
Point B (Hz reduction)
Point A (Hz increase prohibit)
(16.6)
51
