Interesting motor find...

[Tinker1980]

For a number of years the wife and I have had a Kobalt 40 volt cordless weedeater. Recently, the charger gave up the ghost, and it being a Kobalt, another one was unavailing. We ended up with a DeWalt cordless weedeater, which is far and above better than the Kobalt, with a brushless motor... but I digress...

The point is, I now have a 40 volt electric motor, variable speed controller, and no battery. Just out of curiosity, I pulled the motor out of the weedeater. I expected something like a 540 or 550 motor used in cordless drills and RC cars.

I was happy to find out how wrong I was. This is a permanent magnet DC motor approximately the size of a soda can. It purrs like a kitten running on three cordless drill batteries in series (60 volts max really 54 volts nominal) and the little integrated fan moves a lot of air. Have to clamp it down, because it will jump out of your hand with 40 or 60 volts.

So I've this big torquey motor that I can run on cordless drill batteries. I can get 5 ah 20 volt Li-Ion batteries for $40 on amazon. All I need is some sort of sprocket that will fit on what seems to be a 5/16" shaft...

 

[butre]

are you sure the shaft is 5/16 and not 8mm? 8mm is a common size for small electric motors. is the shaft keyed or is it a d shaft or oval shaft?

 

[Tinker1980]

are you sure the shaft is 5/16 and not 8mm? 8mm is a common size for small electric motors. is the shaft keyed or is it a d shaft or oval shaft?

I just eyeballed it... the battery in my digital calipers had died. It could very well be 8mm, and I'll investigate it further this weekend. The shaft is round, with a smaller threaded end.

It appears there are lots of sprockets with 8mm bores. I may be able to have my machinist brother put a flat side on the shaft. I haven't a clue how fast it spins, but since it was a weedeater - actually a pretty good one - I suspect it runs about 7,000 rpm with a 40 volt battery.