Dyno motor drive recommendation 1

[BobM2]

I need to design a small dyno to test our product. It will need to drive and "absorb" power. Near zero to about 700 RPM in torque control. Max torque about 180 in#. I was thinking a vector drive with regen. Any comments?

 

[Skogsgurra]

Sounds OK, Bob.

If I have got the units right (used to SI) you will have a little more than 20 newtonmeter at around 73 rad/second. The power would be close to 1500 W and a 1,5 or 2,2 kW vector drive would be just fine. They can usually be connected to a single phase and that could be a benefit in some cases.

An induction motor (I would select 8 poles for 700 RPM and optimum performance at 50/60 Hz) with or without encoder is your electric/mechanical transducer.

The regeneration is a problem moneywise. Vector drives with regeneration are expensive at these power levels. A braking resistor and a chopper (usually built into the drive) is the safe and easy way to go and you do not loose much energy if you are not planning to regenerate most of the time. Cooling the resistor can be a challenge.

Any qualified drives salesman should be able to recommend the right stuff for this application. Most vector drives have quite good torque control. I would say that you can keep the torque constant within a few percent and read it from the drive with at least five percent. A simple calibration (lever and spring scale or weights) can bring the torque error down to one or two percent.

 

[BobM2]

Thanks much! I'm surprised they measure torque that accurately. I thought I'd have to add a torque cell to the dyno but at only a 5% error I can use the drive's torque readout and control.

 

[Skogsgurra]

You got it! Realistic demands usually saves money.