Any electricians here?

3andstop

Focus
Silver Member
I'm putting together something for a homemade lathe and had an idea of wiring something. I could use input from a real electrician who knows if this is ok.

I'll show you what I'm thinking of ...

In this drawing, I am attempting to wire a variable speed rheostat to a drill which is used to power a home made pool cue lathe, and use a momentary on / off foot pedal switch for safety.

The plug ends on both the rheostat and the momentary on / off foot pedal switch rather than hard wiring it will allow me to disassemble the setup until the lathe is needed (which isn't very often) so wires are not all over.

The objective is to only submit the momentary foot pedal switch to full power from the circuit breaker box rather than expose it to power AFTER the rheostat so it will not overheat from excess resistance. This is why I want the order of the power flow from the circuit breaker, to the momentary switch and THEN ... to the rheostat and finally to the drill.

The main question is my use of the duplex outlet box. It certainly isn't orthodox and for all I know, there may be a specialized plug end configuration to do what I have in mind. This is why I ask.

Rather than normal wiring of white to one side on top and black to the other, I want to wire the Hot (black) wire to the silver (white terminal) on the top plug. Then allow the metal lug to carry the hot voltage to the gold (black side) of the bottom plug.

The white wire will go directly to the bottom silver screw on the bottom plug.

The momentary switch has three wires ... Common, Normally Open, and Normally Closed. I will not be using the normally closed wire.

I want to wire the Common and the Normally Open wires to a Male Plug which I can plug into the top of the Duplex outlet. This will feed current into the common of the momentary foot pedal switch.

When the foot pedal is depressed the circuit will complete and run through the normally open wire back up to the right top side of the Duplex outlet. The steel lug will carry the power down to the hot side of the bottom Duplex plug allowing the Rheostat to be powered.

Can I do this in this manner?
 

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Neil

AzB Silver Member
Silver Member
No, you can not legally do that. I suggest that you take the parts to a local electrical company, and he can diagram it out for you and tell you what parts you need. Odds are, there would be no charge.
 

Drawback

AzB Silver Member
Silver Member
I'm putting together something for a homemade lathe and had an idea of wiring something. I could use input from a real electrician who knows if this is ok.

I'll show you what I'm thinking of ...

In this drawing, I am attempting to wire a variable speed rheostat to a drill which is used to power a home made pool cue lathe, and use a momentary on / off foot pedal switch for safety.

The plug ends on both the rheostat and the momentary on / off foot pedal switch rather than hard wiring it will allow me to disassemble the setup until the lathe is needed (which isn't very often) so wires are not all over.

The objective is to only submit the momentary foot pedal switch to full power from the circuit breaker box rather than expose it to power AFTER the rheostat so it will not overheat from excess resistance. This is why I want the order of the power flow from the circuit breaker, to the momentary switch and THEN ... to the rheostat and finally to the drill.

The main question is my use of the duplex outlet box. It certainly isn't orthodox and for all I know, there may be a specialized plug end configuration to do what I have in mind. This is why I ask.

Rather than normal wiring of white to one side on top and black to the other, I want to wire the Hot (black) wire to the silver (white terminal) on the top plug. Then allow the metal lug to carry the hot voltage to the gold (black side) of the bottom plug.

The white wire will go directly to the bottom silver screw on the bottom plug.

The momentary switch has three wires ... Common, Normally Open, and Normally Closed. I will not be using the normally closed wire.

I want to wire the Common and the Normally Open wires to a Male Plug which I can plug into the top of the Duplex outlet. This will feed current into the common of the momentary foot pedal switch.

When the foot pedal is depressed the circuit will complete and run through the normally open wire back up to the right top side of the Duplex outlet. The steel lug will carry the power down to the hot side of the bottom Duplex plug allowing the Rheostat to be powered.

Can I do this in this manner?

This will work as you have designed. I would just add this as a safety precaution: Be sure to remove the metal strip on the neutral side of the receptacle so that the neutral conductor is disconnected physically from the other terminal directly below it. Your drawing depicts this as already being disconnected, which is good. Then on the footswitch conductor being used on the top left side of the top receptacle, re-identify that as a black conductor by using a magic marker. There will now be two black conductors in that cord as both of them are hot.

If you are using metal boxes, be sure to ground each box with the bare equipment grounding conductor so that in the event of a fault, the overcurrent protective device (circuit breaker) will operate.

Your hook up is not exactly National Electrical Code compliant, but with the necessary safety precautions it will work. Be sure to identify the receptacle as a special receptacle NOT to be used for any other appliance. Also be sure your dimmer is rated for a motor and not just a light dimmer. If not, you may very well burn out your motor on the drill/lathe.
 

3andstop

Focus
Silver Member
No, you can not legally do that. I suggest that you take the parts to a local electrical company, and he can diagram it out for you and tell you what parts you need. Odds are, there would be no charge.

Hey Neil .. yeah I figured it wasn't legal ... but will it work? The thing is I want to use male plugs on the foot pedal and rheostat. Hard wiring inside a box would be a non issue.

For all I know there may be proprietary style duplex receptacles for special applications like this, but I'm more concerned it will work.

Unless I'm missing something (which is totally possible) if someone were to mistakenly plug something into this duplex, there wouldn't be any shorts .. it simply wouldn't work.

My concern is more whether I'm missing something that would make this rube goldberg not work for my application. Thanks for the reply.
 

3andstop

Focus
Silver Member
This will work as you have designed. I would just add this as a safety precaution: Be sure to remove the metal strip on the neutral side of the receptacle so that the neutral conductor is disconnected physically from the other terminal directly below it. Your drawing depicts this as already being disconnected, which is good. Then on the footswitch conductor being used on the top left side of the top receptacle, re-identify that as a black conductor by using a magic marker. There will now be two black conductors in that cord as both of them are hot.

If you are using metal boxes, be sure to ground each box with the bare equipment grounding conductor so that in the event of a fault, the overcurrent protective device (circuit breaker) will operate.

Your hook up is not exactly National Electrical Code compliant, but with the necessary safety precautions it will work. Be sure to identify the receptacle as a special receptacle NOT to be used for any other appliance. Also be sure your dimmer is rated for a motor and not just a light dimmer. If not, you may very well burn out your motor on the drill/lathe.


Thanks for the input ... yes I sure would disconnect the neutral lug and I alway wrap the white neutral with electrical tape to designate line voltage. I'll also mark the receptacle. I was even considering a way to engrave on the steel outlet cover special use ... do not use ... or something to that effect. Maybe painting it red also.

The rheostat is rated for 110v and 15amps electric brush style motors. The drill is a cheapo Home Depot rated at 3.8amps.
 

Drawback

AzB Silver Member
Silver Member
Thanks for the input ... yes I sure would disconnect the neutral lug and I alway wrap the white neutral with electrical tape to designate line voltage. I'll also mark the receptacle. I was even considering a way to engrave on the steel outlet cover special use ... do not use ... or something to that effect. Maybe painting it red also.

The rheostat is rated for 110v and 15amps electric brush style motors. The drill is a cheapo Home Depot rated at 3.8amps.

"Necessity is the Mother of invention" and I think your idea is pretty clever.:)
 

Mickey Qualls

You study the watch......
Silver Member
What about wiring two single outlets (commonly known as air conditioner outlets) to each side of a double pole single throw maintained switch ?

If you've ever seen or used a truck with a lift gate (those are usually three position momentary switches, up/off/down), the switch for your lathe setup would be similar.

Flip the switch one way, it powers the outlet to the rheostat. Flip it the other way, it powers through the foot pedal.
 

3andstop

Focus
Silver Member
What about wiring two single outlets (commonly known as air conditioner outlets) to each side of a double pole single throw maintained switch ?

If you've ever seen or used a truck with a lift gate (those are usually three position momentary switches, up/off/down), the switch for your lathe setup would be similar.

Flip the switch one way, it powers the outlet to the rheostat. Flip it the other way, it powers through the foot pedal.

But that still wouldn't give the foot pedal full line voltage while controlling the power to the rheostat at the same time, would it? The idea is if I'm using the rheostat to slow the drill, and my finger gets stuck, I move my foot off the foot pedal and the drill stops.
 

mamics

AzB Silver Member
Silver Member
The objective is to only submit the momentary foot pedal switch to full power from the circuit breaker box rather than expose it to power AFTER the rheostat so it will not overheat from excess resistance. This is why I want the order of the power flow from the circuit breaker, to the momentary switch and THEN ... to the rheostat and finally to the drill.

I'm a sparky.

I can't quite follow ur explanation & diagram fully ? (though others seemed to ?)

You seem to have some reasonable electrical knowledge (current ratings / wire colour coding)

The quote above worries me a little - "exposure of footswitch to full power to prevent overheating from excess resistance"

What is ur foot switch rated at ? (voltage rating AND current rating) If it's rated at equal to or greater than ur rheostat and ur drill, then I dont see any problems with overheating no matter how u wire it up ?

....unless I'm missing something - I really don't understand the need for the modification / complexity of it to combat an overheating issue ???

Be careful dude.

I would have the footswitch plugging into a regular power outlet.
The footswitch should merely make / break the active conductor.
Rheostat plugs into the outlet side (switched side) of the footswitch.
Why won't this setup be easier / safer & still work ? (I must be missing something ?)

Cheers.
 
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3andstop

Focus
Silver Member
I'm a sparky.

I can't quite follow ur explanation & diagram fully ? (though others seemed to ?)

You seem to have some reasonable electrical knowledge (current ratings / wire colour coding)

The quote above worries me a little - "exposure of footswitch to full power to prevent overheating from excess resistance"

What is ur foot switch rated at ? (voltage rating AND current rating) If it's rated at equal to or greater than ur rheostat and ur drill, then I dont see any problems with overheating no matter how u wire it up ?

....unless I'm missing something - I really don't understand the need for the modification / complexity of it to combat an overheating issue ???

Be careful dude.

Cheers.
In my first life I was an automobile mechanic, if you ever tried to rewire under the dash of a 71 Cadillac that burned the harness, a white and black wire in my warm basement starts to look simple. :)

Well that's the other thing. I usually tend to be more cautious when I'm not sure of something. Both the rheostat and the foot pedal are rated at 15amps.

It probably would work with the pedal downstream of the resistor, but .. I just don't like the idea of introducing the extra heat to the pedal from the resistor if I don't have to. With the pedal first in series it only sees full line voltage so it's a total non issue.

I'm going to use a dedicated 15amp circuit from the main box also. It's a short run to the workbench where the lathe is, and the rheostat has a built in inline fuse.

Not to mention ... I'll have my wife try it out first! :thumbup:

Thanks for the thoughts!
 

Mikjary

Droppin' a Fauci
Silver Member
In addition, don't ground your duplex receptacle. The original neutral connection which you're heating up is connected to the ground connection. :( Also, your rheostat's grounded plug will send a hot to your rheostat housing. Ouch! GL

Best,
Mike
 

3andstop

Focus
Silver Member
In addition, don't ground your duplex receptacle. The original neutral connection which you're heating up is connected to the ground connection. :( Also, your rheostat's grounded plug will send a hot to your rheostat housing. Ouch! GL

Best,
Mike

Oh ... Mike .. .that's a gooooood thought there!!! thanks

Does the neutral screw on the receptacle have continuity to the mounting bracket for the plug to work box? Or is the ground separate and I just shouldn't ground the box. Maybe I should have my wife throw the breaker too. :scratchhead:
 
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mamics

AzB Silver Member
Silver Member
Hmmm - not that I've had much direct experience with rheostats - but is the issue of concern the heat transfer along the conductors either side of the resistor ?

3.8A drill rating.
15A rheostat rating.

I would have thought the design of the rheostat would address any possible heat transfer problems - whatever the rheostat dial is set to ??
 

Cornerman

Cue Author...Sometimes
Gold Member
Silver Member
Let me just say that asking AZ is asking for trouble.

I've built dozens of specially wired AC custom equipment as part of my career. My advice: don't do this. You're basically asking if it's okay to build a shorting switch with common household components. It's the "it looks like a plug" that's thr problem.

Put the switch inline please. And use one that is rated for the power you plan to run through it. Don't use anything that looks like common plugs and outlets as a makeshift relay. Might as well just use a relay.

Freddie <~~~ professionally speaking
 

Drawback

AzB Silver Member
Silver Member
In addition, don't ground your duplex receptacle. The original neutral connection which you're heating up is connected to the ground connection. :( Also, your rheostat's grounded plug will send a hot to your rheostat housing. Ouch! GL

Best,
Mike

The grounding strap on the receptacle shouldn't be electrically connected to the neutral terminals. It should be manufactured to be separate and not connected. Any of the receptacles available in hardware stores have the yoke connected to the EGC terminal, not the neutral. The neutral to ground connection is only permitted in the panelboard with the main breaker in it.

The receptacle should have an equipment grounding screw connected to the mounting yoke of the receptacle and not in any way connected to the neutral strap on the receptacle. Make sure of this. If in doubt, check it with a continuity meter.

It's very important to have the equipment grounding conductors connected to each metal box and to the equipment grounding screw on the receptacle. If a ground fault occurs, it is the EGC that will clear the fault by returning it to the OCPD.
 

Mikjary

Droppin' a Fauci
Silver Member
The grounding strap on the receptacle shouldn't be electrically connected to the neutral terminals. It should be manufactured to be separate and not connected. Any of the receptacles available in hardware stores have the yoke connected to the EGC terminal, not the neutral. The neutral to ground connection is only permitted in the panelboard with the main breaker in it.

The receptacle should have an equipment grounding screw connected to the mounting yoke of the receptacle and not in any way connected to the neutral strap on the receptacle. Make sure of this. If in doubt, check it with a continuity meter.

It's very important to have the equipment grounding conductors connected to each metal box and to the equipment grounding screw on the receptacle. If a ground fault occurs, it is the EGC that will clear the fault by returning it to the OCPD.

Not supposed to be. :) I have had even non grounded receptacles short when the frame is touched by the hot. Who knew?

Best,
Mike
 

Axis_of_Evil

Registered
I'm putting together something for a homemade lathe and had an idea of wiring something. I could use input from a real electrician who knows if this is ok.

I'll show you what I'm thinking of ...

In this drawing, I am attempting to wire a variable speed rheostat to a drill which is used to power a home made pool cue lathe, and use a momentary on / off foot pedal switch for safety.

The plug ends on both the rheostat and the momentary on / off foot pedal switch rather than hard wiring it will allow me to disassemble the setup until the lathe is needed (which isn't very often) so wires are not all over.

The objective is to only submit the momentary foot pedal switch to full power from the circuit breaker box rather than expose it to power AFTER the rheostat so it will not overheat from excess resistance. This is why I want the order of the power flow from the circuit breaker, to the momentary switch and THEN ... to the rheostat and finally to the drill.

The main question is my use of the duplex outlet box. It certainly isn't orthodox and for all I know, there may be a specialized plug end configuration to do what I have in mind. This is why I ask.

Rather than normal wiring of white to one side on top and black to the other, I want to wire the Hot (black) wire to the silver (white terminal) on the top plug. Then allow the metal lug to carry the hot voltage to the gold (black side) of the bottom plug.

The white wire will go directly to the bottom silver screw on the bottom plug.

The momentary switch has three wires ... Common, Normally Open, and Normally Closed. I will not be using the normally closed wire.

I want to wire the Common and the Normally Open wires to a Male Plug which I can plug into the top of the Duplex outlet. This will feed current into the common of the momentary foot pedal switch.

When the foot pedal is depressed the circuit will complete and run through the normally open wire back up to the right top side of the Duplex outlet. The steel lug will carry the power down to the hot side of the bottom Duplex plug allowing the Rheostat to be powered.

Can I do this in this manner?


---------------------------


You are really over thinking this project. Forget all of the extra wiring, foot pedal, etc.

Just use the rheostat (aka: variable speed controller) as it is intended with the drill.

Place this controller close to your work... i.e. the tip end of the shafts. The 1/2 second or so you wold save using a foot pedal contraption vs pressing the controller on/off switch is meaningless.

FYI... you will want to use one of the drills that has a max rpm ~800.. it's ideal... ~500 rpm for tip work and ~500 to ~800 rpm for cleaning, polishing, etc. The max 2500 rpm drill are not a good fit.

Good Luck!
 

Mikjary

Droppin' a Fauci
Silver Member
Let me just say that asking AZ is asking for trouble.

I've built dozens of specially wired AC custom equipment as part of my career. My advice: don't do this. You're basically asking if it's okay to build a shorting switch with common household components. It's the "it looks like a plug" that's thr problem.

Put the switch inline please. And use one that is rated for the power you plan to run through it. Don't use anything that looks like common plugs and outlets as a makeshift relay. Might as well just use a relay.

Freddie <~~~ professionally speaking

^^^^^^ I like this the best of all.

Best,
Mike
 

Nick B

This is gonna hurt
Silver Member
The Engineer in me says....please don't do this. If you can't properly diagram this or don't know whether it will work you are not qualified to do this. How would you feel if you hurt yourself or someone else all in the name of saving a few bucks? Find a friend or pay someone.

An improper ground or wiring mistake can ruin a day or someone's life. Arc flashes occur in milliseconds. You would be amazed how much energy is a behind a 15Amp circuit.

https://www.youtube.com/watch?v=Hp1JdVwbN_U


Nick
 
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