[Stoves] Question regarding motors

[Steve Taylor]

On 29 May 2012 20:27, Frank Shields <frank at compostlab.com> wrote:

> Stovers,****
>
> ** **
>
> ** **
>
> I want to turn a frame holding solution of biochar along with toxicants to
> determine up-take potential. Also to turn wood and biochar  pellets to
> determine hardness. It needs to turn at 30 and 50 RPM. ****
>
> Can I use a ¼ HP motor with a Variac ? I have a motor ordered that turns
> at 52 RPM (gearing included) and would like to fine turn it to 50 rpm then,
> if it will not destroy the motor, adjust it down to 30 rpm with the same
> variac.****
>
>
>
>
> No, sorry, to assuming its an AC motor, you'll burn it out in short order.
AC motors tend to run at a multiple of mains frequency, or a shade off.
When they are run under-voltage, then there isn't sufficient current to
convert into torque, but enough current to convert into heat, and they'll
burn up.

For proper speed control, I recommend an AC inverter drive like this one
from Ebay.
http://www.ebay.com/itm/Allen-Bradley-PowerFlex4-0-25HP-0-230VAC-Drive-22A-V1P5N104-/270941251762?pt=LH_DefaultDomain_0&hash=يتيمعف١خخبطضبء

Steve
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