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.
As a result:
•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 | (20A) | Power Point C |
(16.6A) | Point A | |
| (17A) | Point B |
| Target |
|
frequency |
| |
Frequency | Frequency |
|
| Stops operation |
|
| Approx.3 minutes |
|
•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.)
(1)Automatic frequency control
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 |
| COOL |
|
|
|
|
Point C (peak cut trip) | (20.0) |
| (20.0) |
|
|
|
|
Point B (Hz reduction) | (17.0) |
| (17.0) |
|
|
|
|
Point A (Hz increase prohibit) | (16.6) |
| (16.6) |
NOTE During defrost operation, the COOL current setting value is used.
(2) Current control
The operating frequency upper limits shown in the figure below are established for frequency reduction and
Current(A) Example of operation during cooling
Trip | Hz reduction | |
Hz reduction | ||
Hz increase prohibit | ||
Hz increase | ||
| ||
prohibit |
| |
(16) | Hz reduction | |
Hz increase prohibit | ||
(15.6) | ||
| ||
0 | Frequency (Hz) | |
| (30) | |
| 78 |
