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Jon Danniken[_7_]

On 02/16/2013 08:56 AM, wrote:
On Fri, 15 Feb 2013 22:47:50 -0700, "Steve B"
wrote:

I am going to cannibalize a Sawzall to crack pecans. I need to slow it
down. If I use a dimmer, will that be adequate, and work? Or do I need to
go with a larger rheostat?

Steve

A dedicated speed control will work better than a lamp dimmer because
of the inductive component of the universal motor in a sawzall. A
rheostat will be your least effective solution - a big Variac would
work better - but remember, you will reduce the power of the motor by
a whole lot more than you reduce the speed. What youreally want is a
variable speed sawzall.

A variac does work, but the motor will slow down when a load is applied.
This is one of the benefits to a phase angle controller; because the
motor still gets full voltage, there is far less speed variation when a
load is applied.

I guess it would depend on exactly how the unit was repurposed; maybe
the load used for cracking pecans would be so low that the variac would
work just fine (and then you have an excuse to buy a variac if you
didn't have one before).

Jon