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Wiring a DPST switch to convert DVR to 220V

E

ebrannon

Joined
Oct 22, 2009
Messages
79
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1
Location
Milford, PA
I want to run my Nova DVR XP on 220 volt. I have the new Double Pole Single Throw switch, but not sure the correct wiring. I checked the Technitool web page instructions, but it only says you have to change the switch, not how to do it.

Do I run the white wire from the cord to the new switch (as opposed to the board) and then run the jumper to the board?

I would hate like hell to blow the circuit board by mistake. Electronics was not my thing, I am a forester by training. We like things simple.

Ed
 
John
Because it delivers more power.

Teknatool claims it's 1/2 horse more, reality it's a bit more then 1/4

TTFN
Ralph
 
Ralph,
And what is your basis for that statement? I find no difference in power between my DVR wired at 220 and my Powermatic. If I remember correctly when I got my DVR years ago I picked it up in WV at Tim Geist's facilities and he showed me his layout and he had an outfit that actually tested the HP output of the lathe. He told me that at 220 there was a substantial increase in HP and sold me the part I would need for the changeover. Now I don't believe that he would fib just to sell me a $2 part.🙂
Bill
 
If you use the same power cord to the unit and have replaced the power plug to the wall then the white and black wires are both hot now and need to run to the new switch. It's very important to have a good ground on the remaining green wire in the cord as this is ground and neutral which should remain connected as it is now. Just make sure the green wire has a tight connection on the Nova. It is suggest to have another fuse also on the new hot wire now.
I still run mine on 110v and was going to convert it but have not found the need. You should also find a 220v surge protector which is not cheap. If you don't understand 220v I would find a friend to help.
Good luck
 
Bill

I did the math.

Power conversion is actually basic stuff. Like firms that "claim" you can get 2HP out of any 110V @15 Amp motor

The power increase is real, it's just not as great as the marketing people at Teknatool would like people to think (I suspect they "rounded" the number). Considering the cost (a DPST switch) it is worth the effort for most people
 
110V to 220V = No Horsepower Increase

Before spending a lot of time and money converting your Nova DVR XP from 110V to 220V you should read “The Truth: 240V is Better†by Kara Gebhart & Greg Hyland in the July 2004 issue of Popular Woodworking magazine. At the time this article was written Greg had been in the electrical trade for 33 years and held Electrical Contractor licenses in Ohio and Kentucky, as well as Master Electrician licenses in five local jurisdictions. Greg, unlike many of our woodworking colleagues, has the credentials to speak on the subject of 110V vs 240V.

I offer some quotes from Greg’s article for your consideration.

“You won’t save a dime and your motors won’t be more powerful if you switch to 240V. But, if you’re running multiple motors at the same time or you’re using the pre-existing wiring in your house, switching to 240V will eliminate voltage drops and stalling, as well as lengthen the life of many of your motors. In almost all cases, 240V truly is a better deal.â€

Common 240V Myths - “This, you should know: You won’t save a watt of energy or a single dime by switching to 240V. Whether you’re running a motor using 120V or 240V, the horsepower of the motor stays the same. Remember: One horsepower equals 746 watts, and watts = volts x amps. If your volts go up, your amps go down. If your volts go down, your amps go up. (Watts always stay the same.) The utility company charges you for the number of kilowatt hours you use – not amps or volts.â€

Check the nameplate on the Nova motor. It probably shows that at 115V the motor draws “X†amps. And at 230V it draws one half of “Xâ€. If volts double and amps are one half, watts (horsepower) remains constant.

Greg then goes on to offer five good reasons why 240V is better. But none of them have anything to do with increased horsepower.

In closing the article Greg offers the following:

“Switching to 240V will increase your electrical system capacity, reduce heat, lengthen the life of your motors and in general, make your workshop more efficient. Make the switch. You’ll be glad you did.â€

Again, note that there is no mention of increased motor horsepower. - John
 
Electrical Code Compliance, Anyone?

Using the white lead as a hot and the green as neutral ought to be a sure-fire way to let your insurance company out of their obligation if you ever experience an otherwise insurable loss. There are specific wiring schemas and plug/outlet combinations based on the rated voltage and current carrying capacity of the circuit.

The green ground wire is for safety only--not for carrying the full "return current" normally handled by the so-called neutral conductor. The ground lead is often one gauge size smaller than the other conductors. While true that the neutrals and grounds of all your home's branch circuits eventually tie together (often at your electrical panel, sometimes at the pole--or both, for starters) local modifications to National Electrical Codes may stipulate whether a neutral and ground may be tied together elsewhere. Notice however, that there is no instance where a ground is allowed to serve as a replacement for the neutral.

Even if you're not inclined to hire a licensed electrician to make the necessary change(s), you should consider having one inspect your work upon completion. For more details, Richter, Schwan, and Hartwell's Wiring Simplified is a well regarded reference and definitely worth the cost or visit to your local library.
 
John King said:
Before spending a lot of time and money converting your Nova DVR XP from 110V to 220V you should read “The Truth: 240V is Better†by Kara Gebhart & Greg Hyland in the July 2004 issue of Popular Woodworking magazine. At the time this article was written Greg had been in the electrical trade for 33 years and held Electrical Contractor licenses in Ohio and Kentucky, as well as Master Electrician licenses in five local jurisdictions. Greg, unlike many of our woodworking colleagues, has the credentials to speak on the subject of 110V vs 240V.

I offer some quotes from Greg’s article for your consideration.

“You won’t save a dime and your motors won’t be more powerful if you switch to 240V. But, if you’re running multiple motors at the same time or you’re using the pre-existing wiring in your house, switching to 240V will eliminate voltage drops and stalling, as well as lengthen the life of many of your motors. In almost all cases, 240V truly is a better deal.â€

Common 240V Myths - “This, you should know: You won’t save a watt of energy or a single dime by switching to 240V. Whether you’re running a motor using 120V or 240V, the horsepower of the motor stays the same. Remember: One horsepower equals 746 watts, and watts = volts x amps. If your volts go up, your amps go down. If your volts go down, your amps go up. (Watts always stay the same.) The utility company charges you for the number of kilowatt hours you use – not amps or volts.â€

Check the nameplate on the Nova motor. It probably shows that at 115V the motor draws “X†amps. And at 230V it draws one half of “Xâ€. If volts double and amps are one half, watts (horsepower) remains constant.

Greg then goes on to offer five good reasons why 240V is better. But none of them have anything to do with increased horsepower.

In closing the article Greg offers the following:

“Switching to 240V will increase your electrical system capacity, reduce heat, lengthen the life of your motors and in general, make your workshop more efficient. Make the switch. You’ll be glad you did.â€

Again, note that there is no mention of increased motor horsepower. - John
Click to expand...

John, I'm guessing that Greg's article was "an in general" piece and did not consider that the motor in the DVR is not a conventional electric motor. Nor is it even a conventional three-phase motor found in most variable speed lathes.

One of the real down-sides to the Teknatool Nova DVR/DVR-XP is that the motor (a Digital Variable Reluctance motor) is a propriety motor, made only for Teknatool. While there are other makers of this type of motor, but none that would fit into the head-stock of a DVR/DVR-XP (at least and connect to the electronics, etc)

For a DVR/DVR-XP there is an actual increase in power, but this is due to the special nature of the motor.

...and yes I will see his credentials and raise them with a BS in EE, with extra training in motors and power conversion and 35 years of experience.

TTFN
Ralph
 
Rick M said:
Using the white lead as a hot and the green as neutral ought to be a sure-fire way to let your insurance company out of their obligation if you ever experience an otherwise insurable loss. There are specific wiring schemas and plug/outlet combinations based on the rated voltage and current carrying capacity of the circuit.

The green ground wire is for safety only--not for carrying the full "return current" normally handled by the so-called neutral conductor. The ground lead is often one gauge size smaller than the other conductors. While true that the neutrals and grounds of all your home's branch circuits eventually tie together (often at your electrical panel, sometimes at the pole--or both, for starters) local modifications to National Electrical Codes may stipulate whether a neutral and ground may be tied together elsewhere. Notice however, that there is no instance where a ground is allowed to serve as a replacement for the neutral.

Even if you're not inclined to hire a licensed electrician to make the necessary change(s), you should consider having one inspect your work upon completion. For more details, Richter, Schwan, and Hartwell's Wiring Simplified is a well regarded reference and definitely worth the cost or visit to your local library.
Click to expand...

Em, Rick

Last time I checked, in a three wire 220 cord the white is one hot lead, the black another and the green is usually connected to the neutral. This is, of course, not how the romex is connected, but it is often the case in a 220 three-wire power cord.

A four-wire is different, as it includes the ground. Then the wiring is indeed white neutral, red & black hot and green/bare ground.

But your basic advise is solid, if you don't know what you are doing, get help

Ralph
 
I made the conversion

i made the conversion to 220V. Actually, pretty simple and everything runs fine.

However, the comments were very thoughtful and I am not sure it made much difference in performance, but since I had a 220V plug right next to my lathe (used for another tool at the time) I thought the extra horse power would help. It also put the lathe on a dedicated circuit, which is a benefit to me.

I will send a follow up if I really notice a difference.

Thanks for your suggestions.

Ed
 
I would be very interested if you notice any changes as I have a Nova DVR XP also and have thought about the change to 220v myself.
Glad it went well.
 
Laws of Physics Revised?

Ralph - Are you suggesting that for the motor in the Nova DVR XP the equation watts = volts x amps is not valid?

Hard for me to believe that the "special nature" of the Nova motor violates the fundamental principle of power - watts = volts x amps. For the power of the Nova motor to increase with conversion from 110V to 220V the amp draw must remain constant or at least not be reduced significantly.

This issue can easily be addressed by looking at the label on the motor. It will provide motor amp draw at both voltage levels. If the amp draw for the motor at 220V is something other than one half of the amp draw at 110V, then I can buy in to your case that the power of the motor is increased by switching from 110V to 220V. Otherwise, I'll stick with information presented in my earlier posting within this thread. - John

P.S. Here's a link to the complete article "The Truth About 240V" by Kara Gebhart and Greg Hyland. - J
http://www.popularwoodworking.com/article/The_TRUTH_about_240V/
 
Last edited:
Maybe someone could post a readable, close-up photo of the motor name plate, or some relevant info from the owners' manual. For the usual or typical sort of motor, the hp. and energy consumption rate (watts) are of course equal whether supplied with 110V or 220V. And/but the XP motor (as mentioned) and its controller (for lack of a better term) may not be of the "usual" sort. And so YMMV.
 
Here is the original development paper for the DVR lathe. I have also included page 15 of the manual that shows the HP on the unit with various voltage. Yes it does increase power by going to 220V. In reality according to the manual it is closer to 2.3HP and yes it really does make a difference. I have run mine both ways and noticed a pretty substantial increase.

Alan
 

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Alan, Have you noticed it turning bigger blanks I guess. I really may do it now as I have the 220v outlet next to my Nova but have not been eager to do the upgrade without hearing it does help.
Thanks.
 
Despite having a 220 outlet next to mine I haven't as I haven't wanted to spend the $$$$ on another 220 surge system. I wouldn't feel comfortable in not having the lathe electronics protected by a surge system
 
Where I noticed it most was when I was hogging out the interior of bowls taking very heavy cuts. Torque seems substantially better above 200RPM and about the same below 200RPM.

I have turned quite a bit on the PM 3520, and my DVR XP has every bit as much power as the PM when wired for 220V.

You must use surge protection for the circuit so I used this suppressor. http://www.amazon.com/SOURCE-SQUARE...ref=sr_1_1?ie=UTF8&s=hi&qid=1261930749&sr=1-1 It is not very expensive from this source and the shipping was not very bad either.

For me it was a worthwhile upgrade. Of course you do loose the convenience of being able to plug it in anywhere.

Here is the copy of the conversion paper that I had saved from the old MSN site. I had already sent it to Ed. IMHO it was written better than the one from Teknatool with nice clear pictures. I do not remember whom wrote it as I would like to give credit to them. Remember if you use this information use it at your own risk. I found it helpful when I wired mine. I know it says for DVR 3000 but my DVR XP looked the same.

Alan
 

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