An on again/off again project I am designing is a small electric cart/hoist.
Speed controllers is one of the things I have been looking at.  These are
not cheap but are available from various sources.  The trick here from what
you are describing is do you want a speed controller that maintains a
constant speed regardless of load or a just a manual speed controller.  With
the fancier type you could set it to 200rpm and it will maintain that speed
all the time.  Instant start speed under load will take a motor of approx 50
percent larger than needed to just run the load and speed.  Potters wheels I
have seen to do 20 pounds usually have 1/2 hp motors under them.  I am
thinking a 1.5hp to 2hp motor with a speed controller. Both of these should
be available through your local big box store like home depot or lowes or
even an ace hardware.
jimt

On 8/7/05 11:06 AM, "John Rodgers" <inua@CHARTER.NET> wrote:

> Thanks  Everybody for the inpout on my project. I see I need to give
> more information.
>
> I am building what is known in the pottery and mold making world as a
> "Plaster Wheel". It is somewhat like a potters wheel but the wheel head
> is made of plaster, measures 24 inches in diameter and 6 inches thick. I
> have to have enough horse power to get this thing turning from a
> standstill, and to keep it turning under a load. The static load it will
> carry can be up to 100 pounds. It functions very much like a vertical
> lathe, but cutting plaster instead of wood, so there are also turning
> loads imposed by the turning tools.  Speed control should be smoothly
> and infintely variable from 0-200 rpm at the wheel head. I'm hopping
> that I can get some sort of electrical speed controller that is like a
> potentiaometer which will allow me to just dial in whatever speed I
> want. That would be the ideal. Will consider other methods, though.
>
> Thanks
>
> John Rodgers
> 88 GL Driver
> John Rodgers wrote:
>
>> Fella's - and Ladies .... I need a little help.
>>
>> I  need to  build a  machine that uses a 1 HP Capacitor start 120v
>> electric motor that turns at 3350 rpm. The motor - by way of pulleys -
>> will drive a shaft whose rotational speed  should have a controllable
>> range from 0 to 200 RPM.
>>
>> I'm hoping that some of you folk out there know about such stuff and can
>> help me with suggestions on how to get it done.  - speed controllers,
>> variable diameter pulleys, or what ever. I am open to suggestions.
>> Specifics and specifications would be of a big help.
>>
>> I would appreciate any input.
>>
>> Thanks.
>>
>> Regards,
>>
>> John Rodgers
>> 88 GL driver
>>
>>
>
>