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

1. 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.
2. 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

1. 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
2. control interface
   • Inverter models provide:
     • 0- 10V analog input (for central control)
     • Modbus/CAN communication interface
     • Frequency setting terminal

3. Analysis of operating characteristics

1. 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
2. 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

V. Professional Detection Tools

1. 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.
2. 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)