What materials do I need to wire a VFD to a three phase motor?

[eternalphoenix64]

Hopefully I'm offering new information. Look for something called SO cord. A good starting point on selecting the right gauge is to look at the FLA on the motor nameplate. That motor nameplate will also give you a TON of other info that you can take to any sort of electrical engineering handbook and it will tell you what the requirements are for you to create a safe circuit. For safety, GET A LICENSED ELECTRICIAN.

As far as materials (compiling a complete list, some of which you may have already) - you may/will need:

• overload protection for the motor set to the FLA of the motor(similar to this: http://www.****************/Product...sl1t6ORh6UpCOn-z8uwgOp6p_gKhBVcyO4aAlW58P8HAQ)
• an input for the VFD to know how fast to run
• the VFD
• the motor
• your load cell (not necessary for wiring the motor, that sounds to be fairly standalone)
• Possibly 3 phase fuse holder depending on what's upstream of the outlet (here's some examples: http://ab.rockwellautomation.com/Circuit-and-Load-Protection/1492FB-Fuse-Holders)
• correct size and type of fuses (min. 125% of motor FLA)
• SO cord as mentioned above
• If this is not a standalone system, I assume it is going into a cabinet, so you may need to consider mounting hardware
• It sounds as though this IS a standalone system, you can get an outlet connector to match whatever your outlet is (be sure to meet or exceed the current and voltage ratings of the outlet) and that can be wired up by your electrician with the SO cord
• Mounting hardware/method for standalone system

I'm sure other people can think of more things than that.

 

[James Mcquade]

I'm sorry, but unless something changed recently, I am not aware of SO cord being acceptable for use with a VFD.
you have to use cable / wire rated for use with a vfd.

other questions to ask.
how far is the power source to the drive?
how far is the vfd from the motor?
what is the voltage? 240 - no line load reactors needed
480 you must look at the distances, use shielded cables, line and load reactors may be needed.

as already pointed out, get a qualified electrician to help.

regards,
james

 

[keithkyll]

SO is fine for the input side. Do not size it for the load. It's big because it's being used with 50 Amp service. The ground lead must be big enough to blow the 50 Amp breaker in case of a short.
Specified VFD rated cable for the output. However, I've seen just about everything used except VFD rated cable all the way to 200 HP. The "Licensed Electrician" puts it inside conduit and calls it done, and dares you to argue.

In post #1, he asked about a 25 foot cord.
It's 208/240. Only 1 horsepower. 750 Watts. 5.7 Amps. Line/load reactors not needed.

No mention of VFD rated cable here either. I believe in it, but it's an uphill battle.