Author Topic: Foot Switch  (Read 3700 times)

Offline EIEIO

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Re: Foot Switch
« Reply #15 on: June 14, 2013, 08:04:05 am »
Dustin,   I misunderstood.   I suspect that sending variable amounts of current to the saw by the way of a pedal could damage the motor. 
That is correct - you don't want a potentiometer (variable resistor) on the AC input to your saw. On my original Porter-Cable saw, a dead-man switch worked but killed the light same as the motor. I opened the circuit and found the location of the speed control pot and paralleled it with a resistive pot foot switch to control speed like a sewing machine - but  that's more trouble than it is worth. Holding constant speed is hard on your leg/foot so I tended to just hold it full on or full off. But full off on the pot does not stop the saw - just gets it to minimum speed.

Stick with the Dead-Man switch for on/off and use the saw's speed control and a light that keeps power even when you remove your foot from the switch.
EX-21 arrived 2-1-2013!
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IBMer

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Re: Foot Switch
« Reply #16 on: June 14, 2013, 12:30:32 pm »
Ray,   I had the same thought.  A variable foot switch would work by reducing current to the motor.   Over time, it may damage the motor, like a freezer during frequent brown-outs.     Plus it would make your saw feel too much like a sewing machine  :P :o :P   

Offline EIEIO

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Re: Foot Switch
« Reply #17 on: June 14, 2013, 06:09:21 pm »
The motors in these saws don't directly use the AC input from the wall outlet. They are permanent magnet DC motors. They convert the 120V AC from the wall to DC then use varying DC voltage (by PWM on the P-C) to control speed. Putting a resistor on the AC input does not work.
EX-21 arrived 2-1-2013!
Porter-Cable PCB370SS in the corner
Lancaster Ohio
Ray Hayes - RMHayes@RMHayes.US
www.RMHayes.US

Offline GrayBeard

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Re: Foot Switch
« Reply #18 on: June 14, 2013, 07:12:37 pm »
a word on 'deadman switches'....

I have the one from Harbor Freight and have used ti for about 2 yrs.
Then I bought one from Peachtree...MUCH better!!!

It has a much 'lower' profile and is much more comfortable!!!
Using the HF switch got to the point that in my configuration I was getting 'shin splints' after a few hours of cutting because I had to hold my foot at such a high angle and the one from Ptree is much flatter to the floor and therefore much more comfy!

Think about this when selecting your "DeadMan" switch....

~~~GB~~~

I never really wanted to grow up....All I wanted was to be able to reach the cookie jar...and play with my DW 788

IBMer

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Re: Foot Switch
« Reply #19 on: June 18, 2013, 09:38:39 pm »
The motors in these saws don't directly use the AC input from the wall outlet. They are permanent magnet DC motors. They convert the 120V AC from the wall to DC then use varying DC voltage (by PWM on the P-C) to control speed.

Mine is powered by a Flux Capacitor, so I have no need for potentiometers.   It's the same one I use to generate the twenty thousand gigawannawatts needed to power my time machine.. 

Offline EIEIO

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Re: Foot Switch
« Reply #20 on: June 18, 2013, 09:44:59 pm »
OK then, no need for that kind of pot  ~~~8).
EX-21 arrived 2-1-2013!
Porter-Cable PCB370SS in the corner
Lancaster Ohio
Ray Hayes - RMHayes@RMHayes.US
www.RMHayes.US

Offline Billy in Va

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Re: Foot Switch
« Reply #21 on: June 18, 2013, 10:13:26 pm »
I use the on Off foot switch. tried the dead man type and found it was tiring. I can move my leg in different positions for each cut. Its what works best for me
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IBMer

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Re: Foot Switch
« Reply #22 on: June 19, 2013, 10:14:22 pm »
I use the on Off foot switch. tried the dead man type and found it was tiring. I can move my leg in different positions for each cut. Its what works best for me

Mine has saved my bacon..  Well my fingers a few times.    I've had very small pieces become stuck on my blade and go for a wild ride.   Being able to just lift my foot to stop the saw saved me from some serious pain.

 

SMF

Teknoromi