# Hesitation switch



## hman (Mar 30, 2013)

Lots of folks use a simple center-off DPDT as a reversing switch for lathes and other tools.  The problem, of course, is that with the usual DPDT, you can easily throw the switch past the center-off position and fry it, the motor, or other electronics with the back EMF generated by the spinning motor.

A huge number of years ago I encountered a reversing switch with a unique feature.  It could not be thrown directly from forward to reverse.  You could push the toggle all the way over, but it would not switch beyond center-off.  You had to deliberately let the toggle return to center, then push a second time.

A couple years ago I started on a project to convert my Grizzly G4000 to a DC treadmill motor.  It took quite a bit of searching, but I finally stumbled onto the "official" name for this kind of switch.  It's called a "hesitation switch".  Eaton makes it.  Their part number is 7992K10.

http://www.eaton.com/Eaton/Products...s/Toggles/HeavyDutyHesitationSwitches/#tabs-1

Checking Google today, I found several sources.  Unfortunately, some suppliers, including Amazon, want big bucks (>$80) for one.  Fortunately, Allied has the switch for $24.38 (plus $?? shipping).  

http://www.alliedelec.com/search/productdetail.aspx?SKU=70155812

Current capacity of the switch is 15A@125VAC; 10A@250VAC.  It should be a worthwhile investment in peace of mind for any tool (of the correct current draw) with a reversible motor.

- hman
(John Herrmann)


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## Terrywerm (Mar 30, 2013)

John, thanks for the info. I have seen them before too, but never knew their proper name. I don't currently have a use for one, but will file it away in the back of my mind for future reference. Of course, my memory is like a steel trap.... once something gets in there is never ever gets out again!  :rofl:


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## Splat (Mar 30, 2013)

Splat likey likey hesitation switch.    I used one of them years ago on a contraption I was building. I found it in my parts draw (junk bin  ) and thought it was a regular O-x-O switch and after install it drove me nuts. I finally ran the #s on it and found out it was supposed to act like that.  Now I know its proper name. That's a helluva good idea to use on a VFD setup. I installed a O-x-O toggle in my VFD box but may switch it out for that hesi switch. Just a little piece of mind that could save one's setup. Thanks for the info, John.


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## valleyboy101 (Mar 30, 2013)

Thanks for the info.  I was in the power system business for many years and never came across one. Now that I know there is such a thing I'll keep in the ole memory bank.
Michael


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## Hawkeye (Apr 1, 2013)

Actually, Splat, I was just thinking that the one place I'm safe using an On-Off-On rotary switch is my VFD (Teco FM50). The way it's set up, if I accidentally slide through Off into reverse, it will slow to a stop, then ramp up in the opposite direction. Lots of time to correct the mistake.

In a simple switching setup, having a separate On-Off switch will prevent problems. And be a lot cheaper than the hesitation switch (but nowhere near as cool).


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