Shopsmith Forums

As a reader who has gained much knowledge from everyone here I say THANK YOU.

So as a minor token to pay it forward I thought I’d contribute for a change.

Last week I pulled the trigger on a Mark 7 purchase to replace my 1980 Mark 500. (for the cost difference on an upgrade I’m giving the 500 to my son.). I was looking at a Power Pro, 520, and double tilt upgrade to the 500.

In planning for its arrival, I was thinking of the 120v vs. 240v supply. I’ve read that you can change the plug, make an extension cord etc. to supply it.

I’m going to try the attached pigtail that I made up. This way I can use a normal 120v 12ga extension cord to supply either 120v or 240v. Plus I do not need to replace the plug on the Mark 7 and can go with either voltage anytime.

I understand the danger of this being used in the wrong way (a 120v tool) but will ONLY use it on the Mark 7. (Which is why I painted the receptacles red)

Hope this offers another option, and thanks again.

Steve

Kudos on using 20A plug and 20A receptacle.

IMHO this is a good 'solution'.

However it breaks 'the rules'.

The hazard is as you described, improper use by an unaware user.

For that reason, keep it locked up when YOU are not using it.

I am making something similar, but my reason was that when I go to warmer climates for the winter I don't have to find a rental unit with a garage that has the appropriate 240.

RE: the appropriate 240v -When contacting SS tech they Strongly recommended that I use 2 10 amp single pole breakers, so if that has not been passed on to you, I will do so. They said using 2 15s is just okay (not great), but my electrician explained the reasoning about the 10 amps on each leg to make 240 as safer(still went over my head, but he did a great job of trying to get it there! )
Shopsmith said that $50 for the breakers is a cheap investment for keeping the motor safer!! Either and both convinced me.

Finding 10 amp breakers (the garage is GE rather than Square D) proved to be impossible here, but a search did turn up a couple new (old stock) breakers, so they are on their way.

Next is line protection. The electrician that is doing the work took it upon himself to check out the Tekna motor and their site says to install a surge suppressor for their lathes using the same motor, so I will add one, too. Most surge suppressors that work in foreign markets will handle both 120 and 240 no matter the plug configuration. Which I hope means that the 5-15/5-15r should work just fine.

Back to your adapter -
Chopping off the plug to install a new one each move seemed a bit extreme, so rather than buying one of the 5-20p to 5-15r adapters, we just bought an appliance cord (game me an extra 6 feet of wire) with the the 6-20 plug (240v) and then spliced the 5-15r to it. Same idea as yours, but with a bit of extra wire and the 5-15r instead of the 5-20r. It was explained to me that the 5 designated pieces in the 240 environment and the 15 rather than 20 (since the M& is 7 amps in 240 mode) would be fine " in the position in which they were" which I guess is electrician speak for "they are okay but don't try anything else without calling to verify

If you are NOT going to be the only one with access to your adapter, putting one of those child proof inserts into the "R" end might get anyone else to wonder and ask why its there

Congratulations on your creation and enjoy your new acquisition!!

Be well,

Ben

PS. At the last webinar, I suggested to Doug that SS make something similar to what you have. Then they could put in all the electronic monitoring and safety circuitry. Not going to hold my breath!

The '5' designated parts are 125v. The '6' designated parts are 250v.

The '2 single pole' recommendation is contradictory. They should be ganged(i.e. 2 pole). Overcurrent in either wire causes both breakers to open.

10A breakers for residential house breaker panels are not common since the purpose of the breakers is to protect building wiring and #14 is a minimum size wire which requires 15A breaker protection.

Using 10A over current devices to protect the PP motor makes sense if it's max current draw is 7A, but should be between the receptacle and the cord.

That would require an additional enclosure to contain the 10A breakers.

So combine surge protection with 10A breakers.


Question I have is, what is the max current draw at 125V?

cooch366 wrote: I understand the danger of this being used in the wrong way (a 120v tool) but will ONLY use it on the Mark 7. (Which is why I painted the receptacles red)
Steve

Would it help if you teather the pigtail to the SS power cord (like a chuck key on a corded hand drill) to reduce the likelyhood of it being used for anything else?

Good idea on the teathering to the power cord of the MK7. I'm going to have some sort of removable attachment that I can leave on the power cord when I'm not using it and be able to easily remove it to plug into the 220v outlet. This will allow me to use it with a 120v extension cord. I plan on being religous about it's use and storrage. After thinking about this, I can understand why things like this are not "available". Could be dangerous in the wrong hands.

A couple of questions about the 10amp breakers. What is the advantage / benefit of using them? Is it so they trip out eariler? Also why single pole breakers? If it's wired 220v shouldn't you use a double pole breaker? Wouldn't is cause a problem and/or dammage if one of the singles tripped and the other didn't?

Thanks for the info Ben, I too will give Shopsmith a call to try and understand their thinking and make sure I do this right. Last thing I want to do is mess us the motor.

Also could someone shed some more light onthe advantage / benefits of the surge protection that has been talked about here? What is needed and how to hook it up. I'm thinking that it is probably short money to install if offers additional insurance for the motor. Any info or instructions would be greatly appreciated.

Thanks again... Steve

If you made it longer you could plug it back into itself forming a loop around one of the bench tubes.

When I made mine, it was much longer than yours and also acts as an extension cord. It still can be coiled and hung from the back bench tube. I too added red to the plugs.

cooch366 wrote:Good idea on the teathering to the power cord of the MK7. I'm going to have some sort of removable attachment that I can leave on the power cord when I'm not using it and be able to easily remove it to plug into the 220v outlet. This will allow me to use it with a 120v extension cord. I plan on being religous about it's use and storrage. After thinking about this, I can understand why things like this are not "available". Could be dangerous in the wrong hands. Yep!

A couple of questions about the 10amp breakers. What is the advantage / benefit of using them? Is it so they trip out eariler? Trip at a lower current, not 'earlier'. A breaker sized closer to typical(normal) operational current will trip when current exceeds that(10A) but a larger breaker(15A/20A) might not. Also why single pole breakers? If it's wired 220v shouldn't you use a double pole breaker? I see it that way also. Wouldn't is cause a problem and/or dammage if one of the singles tripped and the other didn't? The problem with 'unganged' breakers is that a single pole will only remove power from one of the two 'hot' lines.

Thanks for the info Ben, I too will give Shopsmith a call to try and understand their thinking and make sure I do this right. Last thing I want to do is mess us the motor. Do let us know how that goes!:D

Also could someone shed some more light onthe advantage / benefits of the surge protection that has been talked about here? What is needed and how to hook it up. I'm thinking that it is probably short money to install if offers additional insurance for the motor. Any info or instructions would be greatly appreciated.

Thanks again... Steve

The surge protection is to protect the electronic components in the power supply from over voltage spikes coming in on the power line. Those spikes are not a problem for an induction motor.

[quote="SDSSmith"]If you made it longer you could plug it back into itself forming a loop around one of the bench tubes.]

How does a 250v plug fit into a 125v socket?

JPG40504 wrote:How does a 250v plug fit into a 125v socket?

Whoops, it shouldn't! I know mine won't as I have a twist lock on the male end. But my cord is long enough to coil around the bench tube to make less available for knuckleheads to mess with, cooch can carry his around in his pocket.