Hi folks. New to the AAC boards. Not an electronics pro...just knowledgable enough to be dangerous...

I have a 1950 Radial Arm Saw that does not have the modern saw-stopping tech built in. When the saw is turned off, it continues to turn for a few minutes. I found the attached diagram for a way to draw current from the spinning motor after it has been turned off. It pulls that current into a coil that heats up, slowing down the blade. Would anyone on the billboards want to help me find the modern parts to allow me to make the 'toaster brake'? I am not at all sure what these things are. If I had a good diagram, I am sure I could build it and put it into service, eliminating some safety hazards with the spinning blade and making for a nice conversation starter.

I have attached the old instructions and picture and diagram of the current switch for the 220v machine.

thanks in advance for any help!
Stephen Neely
Pittsburgh, PA
Woodworker and very amature hacker.

 

You can get the parts from Digikey.
The Diode rect. is a common item, also the low value 10w resistor in place of the brake element.

 

You can do it by using a DPDT power switch where the second pole is simply connected to a fat resistor 5-10ohm range? This one seems a bit complicated. But, the original power switch would have to be removed from this vintage piece.

power

Brake

 

DC injection braking of an AC motor is quite effective and an old well proven method.
.

 

You can do it by using a DPDT power switch where the second pole is simply connected to a fat resistor 5-10ohm range? This one seems a bit complicated. But, the original power switch would have to be removed from this vintage piece.

power
View attachment 283304
Brake

View attachment 283305

Apparently not the best idea. Use the DC break. Check your DM mailbox above (red "1" on it.

 

A separate "Push-Button", which is always "in-Circuit", and ready to be pushed,
even when the Motor is normally Powered, is a very hazardous idea.

The Original-Power-Switch needs to be re-wired to operate a DPDT-Relay
which controls the Power to the Motor,
then a Timer installed to apply the DC-Power to the Motor via a second Relay,
which will be automatically activated, for a pre-set time-period, after the Motor is switched-off.
.
.
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