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Vol. 2.6 © 2020 Hanbell Precise Machinery Co., Ltd. All rights reserved
Adjustment of inverter’s frequency for capacity modulation
1. The increment and decrement of inverter frequency is differentiated according to the loading
mode. When the output cycle time arrives (for example, 30 second), determine the adjustment
of frequency based on the difference between current CHWT and target CHWT.
※
Taking 800RT as an example, 1Hz is approximately 7.2% (58RT) of cooling capacity change
rate.
2. Assuming that the set value of cooling water output temperature is 7°C, neutral zone temperature
difference is ± 0.2°C, output cycle time is 30 seconds, rapid loading and unloading frequency is 1 Hz.
Normal loading and unloading temperature difference is 0.5°C and frequency increase and decrease is
0.5Hz. Change of CHWT and inverter output are listed in the following table
Target chilled water temperature (CHWT), 7
℃
Range
<
6.8
℃
6.5~6.8
℃
6.8~7.2
℃
7.2~7.5
℃
>
7.5
℃
Loading mode
fast unloading normal unloading
Neutral zone
normal loading
fast loading
Inverter output
-1Hz
-0.5Hz
no action
+0.5Hz
+1Hz