Hi everyone,

I am part of a senior design group that is building a dynonameter to test shocks. We are ordering parts tomorrow morning and so I want to make sure that I am not missing anything. I do not have any experience with VFD's or three phase motors but I am doing my best to research and learn more each and every day.

On my parts list I have a three phase motor, a DURApulse GS3-21P0 AC Drive, an input fuse kit for the VFD, a USB to RS-485 adapter (for MODBUS communication), a load-cell, and a temperature sensor.

My question is: To wire the VFD to the motor what will I need? I assume both the VFD and motor do not come with any wires. I need to connect the VFD to a three phase 50Amp outlet that will be used to power the VFD. My guess would be to order a three phase extension cord off a website like Amazon and then cut off one of the ends off and use the leads to wire to the VFD. Any thoughts? I was thinking perhaps an extension cord like this one; https://www.amazon.com/Conntek-RUL6...d=1481208227&sr=8-2&keywords=250VAC+extension

**Note: The extension cord in the link above is a 30Amp-250V extension cord. The power supply outlet is a 50Amp outlet. The motor will only draw a few Amps of current. Is it safe to assume that the extension cord provided in the link will be ok for use (provided that prongs are compatible) along with the VFD and the Power supply outlet?

Thank you!

-Kevin


The Shock Dyno Control System
There will be two phases, a warm up phase and a test phase. The warm up phase consists of running the motor until the shock reaches a desired set temperature, when this happens the motor will stop running and there will be a small delay before automatically proceeding to the test phase. Once the test phase starts, the motor will start again and will run until a desired RPM is reached, during the test phase a graph will be plotting force (from load cell) vs RPM.

 

Not trying to be mean here, but why would you not just buy what ever length of SJO cable in the proper gauge that you need? Will be much cheaper than an extension cord. And the cord you picked is for single phase power, you need one for three phase, that means four conductors not three like your pick from Amazon. Four wires are need one for each "live" connection and a ground.

 

Use conduit for a proper job. Use armored flex conduit for a half ass job. Use an extension cord or SO cord (service cord) for a mickey mouse job.

Your name is on it.

 

I have often used super-flex metallic conduit with TEW/MTW conductors, they should be twisted the full length on the motor side, the ground conductor ran along side.
This precludes the need for specialty shielded conductors often recommended.
To make it easier on the motor, especially if non-inverter rated, a 3phase inductor/choke on the output side is a plus.
Max.
.