Compressor Speed Control - Fujitsu AUXB04GALH Service Manual

2-3-2 Compressor speed control

(1) Speed range and controlling
- On operation range: 20 - 115 rps*
- Changing interval: 60 sec.
- When the multi connection outdoor unit has the same type of compressor, all of compressors rotational speed are controlled
with the same speed at the normal operating condition.
- All of the outdoor unit compressors must start at the start-up process.
- The Normal start process (Except the condition of Cold start)
The first target speed is decided by indoor unit capacity demand.
The upper limit speed at starting is made 60 rps and is raised in 30 rps to 90 rps after 60 seconds.
(The upper speed limit depends on the operating high pressure value)
[rps]
115
90
60
Hold 60 seconds
60
- The lower limit speed at start-up changes depending on the outdoor temperature
[rps]
65cc (79cc) type compressor
74(60)
37(30)
24(20)
- 10
Outdoor temperature
- Cold Start start process
Condition: Outdoor temperature below 21
Control HP*: Change the rps so that high pressure does not reach to protection condition
[rps]
Process 1
70
1 min or Max.15 min.
Normal control starts
[sec]
120 180
[
7
21
and the system stopped for more than 1 hour]
Process 2
Process 3
Control HP* Hold
30 sec. 10 sec.
Maximum speed: 80rps
3.80MPa
Maximum speed: 90rps
3.25MPa
*The maximum speed: 115 rps
---> Cooling 100 rps
]
Normal control starts
[sec]
02-05
Heating 115 rps