Something like a mirror ball motor

[J Pearce]

I'd separate the fixing of the arms from the spinning. Fix the arms to a hub and axle that fix to a frame with reasonable bearings - eBay cheapies ought to do fine.

 

Then use a smooth belt drive (if anything stalls it or catches the spinning thing the belt can slip, avoiding stalling the motor and limiting the risk of it removing limbs from people) off to a motor, this also opens up gearing options to get the speed you want.

 

From a quick browse I reckon you could get all the parts you need on eBay for under £40.

[Dave m]

Sorry for the delay - been awayYes- it spins like a clock.

I would check (maybe do) any wiring and PAT anything, normal RAs done as a matter of course done to anything that hangs/spins/moves

I think money is likely to be the biggest impediment as I hope to find a solution that will work (or components) first time around as there won't be the budget for a second go

This will need to be able to run 8 hours a day for a month as part of a final degree show

She does have the idea of somehow having it on a pyramid type structure made of tubing but I did point out that it was likely to need a chain drive/ big/small wheel to control the rotation speed. I could buy a toothed belt and pulleys from China .

 

[J Pearce]

I'd use a v belt rather than a toothed belt, if the tension is set appropriately this will allow it to slip if something goes wrong rather than stalling the motor or tearing itself to shreds.

[Dave m]

Lets' say the arms come to a total of 5kg. What sort of torque figure do I need to look for on a motor?

[Brian]

Lets' say the arms come to a total of 5kg. What sort of torque figure do I need to look for on a motor?

 

1) What speed does it need to turn at?

2) What acceleration does it need?

3) How balanced are the arms?

[Dave m]

The arms are cut out of mdf. 9 or 12 mm and are somewhere between 500-600 mm ( child to small adult size) I assume that they are evenly spaced onto a central hub of some sort

I need to look at it to find out

I had a thought about a rotisserie motor?

[ninjadingle]

Are the arms spinning in free air - or is there a backing plate? Thinking if the arms could run along a circular track this could take more of the load off the motor?