Frequency Control - Mitsubishi Electric PURY-P200YLM-A(1) Service Handbook

[5-2 Outdoor Unit Control ]
5-2-6

Frequency Control

Depending on the capacity required, the frequency of the compressor is controlled to keep constant evaporation temperature
(0°C [32°F] = 0.71 MPa [103 psi]) during cooling operation, and condensing temperature (49°C [120°F] = 2.88 MPa [418 psi])
during heating operation.
The table below summarizes the operating frequency ranges of the inverter compressor during normal operation.
The OS in the multiple-outdoor-unit system operates at the actual compressor frequency value that is calculated by the OS
based on the preliminary compressor frequency value that the OC determines.
Model
P200
P250
P300
P350
P400
P450
P500
EP200
EP250
EP300
EP350
EP400
EP450
EP500
The maximum frequency during heating operation depends on the outside air temperature and the dipswitch settings.
(1) Pressure limit
The upper limit of high pressure (63HS1) is preset, and when it exceeds the upper limit, the frequency is decreased every 15
seconds.
The actuation pressure is when the high-pressure reading on 63HS1 is 3.58MPa[519psi].
(2) Discharge temperature limit
Discharge temperature (TH4) of the compressor in operation is monitored, and when it exceeds the upper limit, the frequency
is decreased every minute.
Operating temperature is 115°C [239°F].
(3) Periodic frequency control
Frequency control other than the ones performed at start-up, upon status change, and for protection is called periodic frequen-
cy control (convergent control) and is performed in the following manner.
Periodic control cycle
Periodic control is performed after the following time has passed
30 seconds after either compressor start-up or the completion of defrost operation
30 seconds after frequency control based on discharge temperature or pressure limit
The amount of frequency change
The amount of frequency change is controlled to approximate the target value based on the evaporation temperature (Te) and
condensing temperature (Tc).
HWE1314A
Frequency/cooling
Max Min
52Hz 10Hz
65Hz 10Hz
74Hz 16Hz
95Hz 16Hz
97Hz 16Hz
111Hz 16Hz
120Hz 16Hz
52Hz 10Hz
65Hz 10Hz
74Hz 16Hz
95Hz 16Hz
97Hz 16Hz
111Hz 16Hz
120Hz 16Hz
- 138 -
Frequency/heating
Max Min
58Hz 27Hz
74Hz 27Hz
92Hz 29Hz
107Hz 29Hz
107Hz 29Hz
124Hz 29Hz
129Hz 29Hz
58Hz 27Hz
74Hz 27Hz
92Hz 29Hz
107Hz 29Hz
107Hz 29Hz
124Hz 29Hz
129Hz 29Hz
GB