Wiring Braking Resistor

I have a 2.2kw 220 volt HY VFD powering a 1.5KW spindle. I ordered and just received the recommended 70ohm/300 watt resistor for braking. I want to position the resistor outside my diy electronics cabinet - mounting it directly to a piece of 1/4 aluminum plate I had on hand, and then the plate to the wall (with standoff). The leads on the resistor are pretty beefy and the outer coating looks like a heat resistant woven coating. From the VFD to the resistor’s leads, do I need anything special for wire? I was going to just use two short lengths of 12 gauge wire (trimmed from an old extension cord).

I would make sure the wires going from the drive to the resistor were the same size or pretty close to the same size on the resistor. As for the type of wire you should be good with using what you have as long as they don’t get close to the resistor.

Hey John,

in my VFD manual, there are the following notes regarding braking resistor:

  • The cable from the external resistor to the inverter must not exceed 5 m
  • The individual wires from the resistor to the inverter must not be bundled

Also you are told to use

the same wire size for the resistor as for the other power lines

e.g. to motor (there is a table for wire sizes with one column for power lines and one column for signal wires. The wire size depends on the model). Also it says:

  • “USE 60/75 C Cu wire only” or equivalent.

Also it says:

  • Keep the Inverter away from heating elements (such as a Braking Resistor,
    reactor, etc.).