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
The operating frequency upper limits shown in the figure below are established for frequency reduction and
increase-prohibit.
(2) Current control
(230)
(223)
(212)
Trip
5Hz every 30 sec. reduction
2Hz every 30 sec. reduction
No control
Increase
prohibit range
(Hz reduction)
(°F)
Compressor discharge temperature
(194)
Within the increase-prohibit range, the range changes
to the Hz reduction range (2 Hz every 30 seconds) if
the compressor temperature rises by 4 °F.
*
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.
7-2-2. Low Start Current
To protect the compressor coil from overheating, the operating frequency is controlled based on the compressor
discharge temperature.
7-2-3. Compressor Temperature Control
70