
How to judge whether a scroll compressor is frequency converted
To determine whether a scroll compressor is a frequency conversion model, it can be comprehensively identified through the following five dimensions:
1. Equipment identification observation
- Nameplate marking
Inverter models are usually clearly marked:- “Inverter”
- “Variable Frequency”
- “Frequency conversion drive”
- example: The nameplate of Mitsubishi compressors is marked with “FV Series”, which represents the inverter model.
- Technical Manual Parameters
Review technical documentation for:- Frequency range (e.g. 30-90Hz)
- Frequency conversion control methods (such as vector control/V/F control)
2. Control system testing
- Existence of frequency converters
- Inverter compressors must be equipped with independent frequency converters (usually located in the electric cabinet)
- appearance characteristics: The inverter has a cooling fan, digital display, and frequency adjustment knob
- control interface
- Inverter models provide:
- 0- 10V analog input (for central control)
- Modbus/CAN communication interface
- Frequency setting terminal
- Inverter models provide:
3. Analysis of operating characteristics
- start-up characteristics
- Soft start of inverter compressor (current rises slowly)
- The starting current of the fixed frequency compressor is 5-7 times the rated current
- noise change
- Inverter models reduce the noise by 3-5dB(A) at 50% load compared to full load
- The noise of fixed frequency models is basically constant
4. Comparison of energy efficiency ratios
load rate | Inverter model EER | Fixed frequency model EER |
---|---|---|
100% | 3.2-3.5 | 3.0-3.3 |
70% | 3.0-3.3 | 2.5-2.8 |
50% | 2.8-3.0 | 2.0-2.3 |
V. Professional Detection Tools
- clamp ammeter
- Measuring operating current: Inverter models reduce the current significantly under partial loads
- example: The full load current of the 11kW compressor is 22A, the current of the inverter model is about 12A at 50% load, and the fixed frequency model still remains at 20A.
- spectrum analyzer
- Test the vibration frequency of the motor: There is a deviation between the frequency of the inverter model and the power frequency (50Hz)