I have a project coming up where I am going to need a decent sized 24v (preferably) geared motor.
10mm shaft, 18RPM (Which I shall halve with the chain drive gearing) and it will be driving a 1200mm diameter steel water wheel.
The wheel doesn't have any water on it (its just a prop), but this thing is going to be heavy, made out of 4mm sheet steel. So there is going to be some momentum there to cope with.
Ideally, I would drive it off some kind of speed controller / H-bridge, so that I can introduce some controlled starting up and slowing down ramps to remove any weight loading.
But... trying to find a UK based supplier is proving difficult. SteppersOnline for instance have some great stuff, but it all ships from China and I don't have the timescale for that.
Anyone got a decent (and not exorbitant cost) UK supplier idea?
You might try a general google search for reconditioned motors using your preferred search engine.
Mechanical isn't my area of expertise but maybe deciding on the HP of your motor would help narrow things down.
Something that is probably easily acquired anywhere is an old windscreen wiper motor. It'll be 12VDC but would that sort of thing work with the appropriate gearing? I don't know much about HGVs but do they use 24V - wonder if they have 24VDC wiper motors?
Trucks usually use 24 volt. It's worth trying. As wiper motors are DC powered a H-bridge is the right one.
Go to a scrap yard and ask!
Steppers are hardly good in Your application.
Well this is the slight issue. I am not entirely sure how to calculate the NM I require etc.
It's also a bit of a guess at the moment how much it will all weigh.
What I do know is a 1200mm metal wheel, 10" wide with metal water buckets around its circumference is gonna weigh a lot.
I have used the windscreen wiper style motors before and they are pretty decent. But... they are usually only 40% duty. Not designed for 100% duty (running all the time).
I just tried a 50RPM wiper motor on 24v through a BTS7960 43A H-Bridge (because I had those kicking around). At anything but full speed the whine from the motor was horrible.
I could probably mess with the PWM timing, but to be honest I think the H-bridge idea is a non-starter for such a low speed.
Maybe if I get a 24v 6RPM Wiper style motor and go from there. Had no luck yet anywhere else (so tired of finding 'UK' stores to then find out they are actually in China).
My only concern is 'whiplash' / momentum. Driving such a large wheel directly off a gearbox with gears and chain is leaving zero flexibility.
I should add there is an Arduino going on this! That was going to be the speed control, lighting and encoder position reader (they want it to stop at exact positions).