Shopsmith Forums

[quote="JPG40504"]Your logic does not include the inductance of the motor. With a collapse of a magnetic field is the dissipation of the energy stored in that field. This results in an arc across the suddenly opened contact points. Those switch contact points must be capable of absorbing the heat generated by the arc. There is also the starting surge current which is considerably more than the normal running current.

If we were switching a purely resistive load, yer logic would be correct.]

What is the salient point here. If I get a 15amp switch from a respectable source am I not in business. Just don't shop price tag first; $5.41 is not a bad price for a good switch.

A large majority of us determine HP by counting the number of Clydesdales in the team.

I really wish I had an extra switch around to look at, or I was inclined to look inside a headstock, so all I remember is that I got a switch with a couple of amps to spare, like 15 or 20 & have used them in mine & others with no issues over several years. (I tend to think of my solutions as good if they work over time) I think my choices of G-B switches at Menards were one that was way too inadequate & the other more than needed, which I bought. I know that's vague, one was like 4-6 amps & one was 15 or 20 which I used. It seemed like a simple choice.
I like to keep stuff simple...use stuff that works that's readily available. I hate making stuff complicated & math formulas...I know, I know, I used one above. I just wanted to pretend that I know stuff.

I am not inclined to declare what should be installed (as a minimum) for a power switch in a Mark V but the switch in mine is labeled as follows:

HY7 20/12A 120/250A AC

This indicates to me that the switch works equally well as a 20amp switch in a 120vac circuit and as a 15amp switch in a 250vac circuit. There is no HP rating on the switch.

http://www.zpaul.com/z09/index.php?act= ... oductId=97

After looking at Dusty's link to a new style switch, I realize I was talking about the older plain toggle switch in the old machines. So, if we're referring to the newer safety switch, regarding what I said, I didn't get one at Menards, but the amp stuff still applies.

trainguytom wrote:After looking at Dusty's link to a new style switch, I realize I was talking about the older plain toggle switch in the old machines. So, if we're referring to the newer safety switch, regarding what I said, I didn't get one at Menards, but the amp stuff still applies.

Bill Mayo gave the best link to the old style switch earlier in this thread.

dusty wrote:Bill Mayo gave the best link to the old style switch earlier in this thread.

Agreed, but the dpst is a better 'fit'.

trainguytom wrote:I think I got the last replacement switch I used at Menards. I believe the maker is Gardner-Bender. I think it's just a double pole, single throw switch.(I might not be remembering the "single/double" thing correctly, but It looks like the SS switch & mounts easily. Just make sure you get one with load capacity comparable to what you have. It's a cheap easy replacement

I stopped at Menards for some misc. & thought I'd make a note of what my poor memory failed to recall.
The switch I've used on several older machines is: http://www.menards.com/main/electrical/wiring-devices/switches/toggle-switch-on-off/p-1460470-c-6324.htm

It's rated 20 amp @ 115v and 1 1/2hp. They're about $4.00

I was getting my replacement switch's from Ace Hardware, but they didn't last any longer than the Shopsmith ones. I just replaced mine with one that looks like the one that Bill says he has been buying.

JPG40504 wrote:Agreed, but the dpst is a better 'fit'.

Yes, I agree. I did not mean to select a dpdt for this application.

joedw00 wrote:I was getting my replacement switch's from Ace Hardware, but they didn't last any longer than the Shopsmith ones. I just replaced mine with one that looks like the one that Bill says he has been buying.

Only the terminals(screw) are a 'misfit'. Otherwise good choice(and for $4?)!