Operational Frequency Control Of Outdoor Unit - Mitsubishi Electric MSC-GE-VB – E Service Technical Manual

2-8-5. Control Method of Rotation Times
Sine wave control makes the current transformers conduct real time detection of the value of the current running into the mo-
tor, locates the rotor position from the detected value, and decides if voltage should be impressed and if frequency should be
changed.
Compared to the conventional control and rotor position detection method, sine wave control can provide fi ner adjustment of the
voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.

2-9. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT

1. Outline
The operational frequency is as follows:
First, the target operational frequency is set based on the difference between the room temperature and the set tem-
perature.
Second, the target operational frequency is regulated by discharge temperature protection, high pressure protection,
electric current protection, overload protection, and the maximum/minimum frequency.
2. Maximum/minimum frequency in each operation mode
Applied model
MUZ-GC25
MUZ-GC35
MUZ-HC25
MUZ-HC35
MUZ-FD25
MUZ-FD35VA
MUZ-FD35VAH/VABH
MUZ-FD50
MUZ-GE25
MUZ-GE35
MUZ-GE42
MUZ-GE50
The operation frequency in COOL mode is restricted by the upper limit frequency after 0.5 - 1 hour as shown
below for dew prevention. It is rated frequency or less.
Upper limit
frequency
COOL
Minimum Maximum
32
32
28
28
10
10
10
20
24
20
10
20
Maximum
frequency
Rated frequency or less
0.5 - 1 hour
Operational frequency (Hz)
HEAT
Minimum Maximum
85 28 105
98 48 105
85 28 105
98 28 98
52 18 90
62 18 90
62 18 115
85 20 130
93 32 105
98 32 98
90 18 115
98 20 108
Time
20 20
DRY
Minimum Maximum
32 41
32 58
28 41
28 41
28 41
28 41
28 41
20 45
38 48
38 55
35 54
98
20