Re: [CAD_CAM_EDM_DRO] Re: Hysteresis Brake

Earle,

Neat idea! I might add that a source of cheap (as in free) shaded pole
AC fan motors is defunct microwave ovens. Pick them up at the curb on
trash day, or at the local recycling center.

The little transformer on the oven control panel usually has a diode
bridge and filter cap, and might have just enough current output to
drive the brake. Can't beat free for that, either!

Dave

erich10983@... wrote:

> I've done this several times for low torque payouts for sapphire fiber and wire wound resistor machines. The simplest and best approach is to use a shaded pole motor with DC on the motor coil. A shaded pole fan, rated at 120 VAC can be driven by a 0 to 24 VDC to give a very smooth, completely controllable viscous drag to your payout spool. This is very inexpensive and works about well as any of the commercial systems I've seen.
>
> As an extra, I've mounted a pot with a swing arm to monitor the diameter of the payout spool to control the torque as the diameter decreases.
>
> Earle Rich
> Mont Vernon, NH
> LaBelle, FL (Way south of the tornado damage here in Florida)
> Posted by: "Graham Stabler" eexgs@... eexgs
> Sat Feb 10, 2007 4:09 am (PST)
>
> Is it possible to make a simple manually adjusted hysterisis brake for
> fairly low torques to be used in wire tensioning?
>
> Does anyone have any experience with this and indeed does anyone have
> an idea of the cost of commerical units including electric versions?
>
> Cheers,
>
> Graham