Generator Motor

[fitek]

I received the Unite motor yesterday afternoon. Unfortunately the sprocket does't work with a bike chain. It's a bit more heavy duty.

I bought #25 sprockets but those have pretty small teeth. I guess I'll buy some #25 chain and swap sprockets.

Oh, there is no freewheel.

I also got 4 SLA batteries from a UPS. They were not doing so well in the UPS, but they have enough juice to turn this motor, and, hopefully, be useful for some testing

 

[fitek]

Forgot to metion that I also bought two Kollmorgens from Bob Mcree. I'll look for a rectifier to use on those.

I also found a treadmill by the side of the road and pulled the motor out. It is a 2 hp, 120v permanent magnet motor. Rated for 3000rpm and 8a.

 

[bobmcree]

i have sold all the motors i had with blown controllers. thanks for the interest. these motors are great for testing controllers on the bench as they will run on 24v at less than an amp, so you can use a current limited power supply when debugging.

i still have plenty of working ones.

 

[fitek]

Still having problems mating the motor and cranks. I tried to pull apart two donor crank sets but they were all rusted. I ordered an 80 tooth #25 sprocket and an 11 tooth one. The 11 tooth has a sloppy fit and the 80 tooth has holes that are not helping with mounting to a bike crank. I ordered some #35 chain and #25 and another small sprocket. If I can't get the #25 sprockets working, I will have some made by my buddy with a cnc machine. Then it should fit whatever I dream up.

 

[vanilla ice]

Which 11t did you order??

 

[fitek]

I got the 8mm D shaft 11t sprocket from TNCscooters.com. It's $5. Not sure about the quality of their stuff, as all I got was the motor and two sprockets, but they were very quick with the shipping. I had the parts in like 3 days. Of course they charge more on shipping than, say, electricscooterparts.com but I bought enough stuff that the cost was spread out.

The chain should be arriving this week, so hopefully I can make some progress this coming weekend.

I just visited a bicycle store and looked at some internal gear hubs. I had heard these mentioned on this forum before, but didn't know what they were. Bicycle Science 3rd ed mentions the Rohloff internal hub. Unfortunately all very pricey, near $200... except for the 3 speed Shimano, at $70. It's easier to get a bigger motor and more batteries than mess around with that stuff.

 

[vanilla ice]

Thats too bad the 11t doesnt fit tightly. There are some ~7.95mm shaft standard sprockets that maybe you could file out so they would fit snugly. I remember seeing a link here at ES for a robot supply place that had unhardened steel ones for like $2 or $3 each if yours isn't working out. I can't find the link now...

 

[fitek]

Heh, just stumbled across my own thread. I wanted to update this for anyone who should come looking at it in the future.

I am currently running the Unite MY1018z 36v with the middle chain ring from a front crank set and with it's stock sprocket on the motor shaft, using 1/8" BMX chain. It is wired through the largest diode I could find at the store to ONE 12v battery. I attempted all sorts of gearing using different chain types to charge a whole 24v pack, but it was simply too difficult. When I make it to Home Depot, I will just use a light switch to swap which battery I am charging. I am able to generate up to 40v and 10-15amps of current if I pedal really really fast. A leisurely 60 or 70 rpm produces about 5-8 amps. There is no resistance to the pedaling when I pedal very slowly, but once the motor makes more than 12v I can feel it gets harder to pedal. The BMX chain gearing of something like 3:1 is about right. I ran 2:1 earlier and I had to pedal at about 100 something RPM to get a decent charge going.

Next thing to try: pedal a DC hub motor.