(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) | |
| Low Start Current |
Operation starts at (8 Hz), and the start current is less than the normal operating current. This prevents the flickering of fluorescent lights or television screens that occurs when ordinary A/C units start.
7-2-3. Compressor Temperature Control
To protect the compressor coil from overheating, the operating frequency is controlled based on the compressor discharge temperature.
Compressor discharge temperature
(°F)
Trip
(230)
5Hz every 30 sec. reduction
(223)
2Hz every 30 sec. reduction
(212)
Increase
prohibit range
No control
(Hz reduction)
(194)
*Within the
70