When and Why to Use Line choke or Input choke for  ac drive / VFD? 

Line choke or input choke is nothing but like a transformer. Its basic function is to protect drive from surge voltage or over voltage spikes in the Mains input supply to VFD.

Ac drive works on switching principle hence it produces harmonics and disturbs mains Line. Line choke helps in controlling the harmonics produced by AC drives or VFD.

Line chokes are recommended to installed right before VFD input.


Line chokes should be connected under following circumstances

1. If Main Line Supply has significant disturbance, this might be due to other equipment or machines such as welding machine, major Inductive types of loads etc.

2. If you are switching your mains supply with generator supply frequently.

3. If You installed  many ac drives at same place or same line or same Same panel.

4. If you have power factor correction capacitors at mains line supply.

5. If there  voltages variations in any of two phase more than 2% than the rated Voltage supply.

Wiring Schematic For Line Choke

It is recommended to use line choke or input choke for every ac drive installation. This not only protect your VFD  but also increase its life.

If you need any help related Line Choke or Line reactor please feel free to contact us or you can email us to info@solims.com.

We will be happy to help you


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