Chassis dyno

[rkosiorek]

i am looking for some ideas for a dynomometer that can be used to check hub motors once they are mounted in a rim.

i am thinking of an open class electrathon vehicle and i would like to be able to test motor and controller combinations.

i have tried google and other search engines but the designs are either too large (motorcycle/car) or too small (rc models) or require the purchase of expensive load cells and or software. so if any of you have seen something on your internet travels i would appreciate the suggestion.

rick

 

[Toorbough ULL-Zeveigh]

Something like <A HREF="http://www.ebikes.ca/simulator/">this</A> which Justin used to model the simulator.
Good only to 5 N-m, I guess you would need motors big enuf to offer equal or greater opposition to the motor under test.
Whatever you find pls keep us informed of your progress, this subject has be discussed briefly b4 centered around modifying an excercise treadmill.

 

[rkosiorek]

i like it. add a dial indicator and it could also be used for building wheels.

seriously though, i was thinking more about the electronics end of it. and if there is any software out there to simplify the task or do i have to do it allfrom scratch?

rick

 

[fechter]

I built one from a bicycle trainer that used about 4" rollers.
The tire had a tendency to slip on the roller, so the geometry had to be changed a bit so the torque helped hold the tire against the roller.

The roller was attached by a belt to an old brushed motor used as a generator. The output of the generator was sent to a load bank made out of giant surplus resistors. I used several switches to reconfigure the resistors to get different loads.

One problem was the load was a function of speed. Some kind of constant current thing would be nicer. Possibly a modified car alternator would be better. The field current could be controlled to give a constant output current (load torque) over a wider speed range.

With a car alternator, you could also continuously vary the load while running, more like an automotive dyno.

Either way, you then use something like a CycleAnalyst to measure the power output of the generator. Knowing (or guessing) the efficiency of the generator, you can calculate the power at the wheel.