Motion control for a rotating a cylinder

[Whynotreuse]

Hi, I am an inventor with mechanical expertise but I am a novice with electrical controls. I want to control the rotation of a horizontal cylinder so it rotates 360 degrees, returning to the same start/stop position each cycle. The cylinder is being driven by a 1hp 110v electric motor, at a rate of one revolution every 124+- seconds. The solution should also include a means to program 1 to 6 start/stop times on a 24 hour basis. I imagine some sort of angle position sensor is available. I would appreciate any thoughts.

Mark

 

[dlgoff]

Welcome to PF Whynotreuse.
I am assuming you are using some gear reduction between the motor and cylinder? I would think the momentum of a 1hp motor would make it difficult to get it to stop right at 360 degrees. How accurate do you need to be?

 

[Whynotreuse]

Welcome to PF Whynotreuse.
I am assuming you are using some gear reduction between the motor and cylinder? I would think the momentum of a 1hp motor would make it difficult to get it to stop right at 360 degrees. How accurate do you need to be?

Thank's for your reply.
It has to be very accurate. I was thinking the momentum would be relatively constant (6o:1) reduction ratio. Therefore my thoughts would be an adjustible sensor which stops the cycle perhaps a degree or two before 360 degrees. This should allow for the (X) degrees of movement from momentum. The cylinder is driven by sprocket and chain with a tension device removing the slack. More data available should you need it.

 

[Bob S]

You could put a retro-reflector and a photo-detector on the outside of the cylinder, or a small hole in the cylinder with a light behind it, or a micro-switch, to stop rotation every 360 degrees. After a pause, you could have a timer that starts the motor again. You could get very accurate positioning if you used a dc motor rather than induction, but they are more expensive.

I have (in my hand) an isolated single phase solid state switch that is rated at 120 V, 25A that I paid ~$10 for about a year ago. I don't know how good it is for inductive loads.
Bob S

 

[Whynotreuse]

Very helpful. I like the idea of a micro-switch since this device operates under harsh conditions and a photo sensor may get dirty. Any idea who supplies the kit necessary to get this done?

Thanks

Mark

 

[Bob S]

Very helpful. I like the idea of a micro-switch since this device operates under harsh conditions and a photo sensor may get dirty. Any idea who supplies the kit necessary to get this done?

Some industrial supply hardware stores have microswitches, but they can drive only an amp or two. So you will also need a relay or contactor that can drive the 1 HP motor.
Bob S