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DVR to 220vac

E

ed crumbley

Joined
Jul 31, 2010
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Location
texas
Okay, I got my Nova DVR, and it is wired for 110. I have 220 and there are no instructions in the manual on how to wire it for 220. I would guess you put ground on the neutral line and 110 on the other two lines? Is that correct? Anything internally?
 
110V vs 220V

Hi Ed,

I went and took a look at the manual, it seems to say you get either a 110V or 220V unit, that the model numbers for ordering are different too.

You may have to contact Nova service for this one.

Good luck

Tom
 
Nova Users Group

There is a Nova Users Group through teknatool. Its a lot like this forum but caters to Nova owners. There are many threads on that subject. It can be done...those guys will know how to do it.

Good luck
 
There is a Nova owners group. Get a hold of Bill Blasic and he will get you there. I posted on the conversion over at the site with good detail. However the newer ones are a bit different. If yours is a newer one just give Tim Giest a call at the US service center and he will set you straight.

Good Luck

Alan
 
All of the DVRs I am familiar with can be converted from/to 110V and 220V.

Contact Tim Giest for exact info.

The user group posted at Teknatool is the old MSN Group, even though MSN shut down all groups a couple of years ago.

Teknatool has a Facebook account, but that is mostly announcements and such. But I have seen questions answered there also.

There is a private Teknatool users group on a web-site, but you have to be personally invited to join

There is also a Yahoo group

TTFN
Ralph
 
Don't speculate when it comes to wiring something or you might let the magic smoke out.

Rule 1 is that you never ever connect ground and neutral together or swap one for the other on any piece of equipment or anywhere else in the building wiring except at the main service entrance -- this also means NOT at any sub panel either. This rule is non negotiable.

If the equipment has provisions for 240 VAC operation there will be terminals on the controller for that purpose. You can't just arbitrarily hook wires up to the power source and hope that it will work. If it is indeed designed to operate on 240 VAC, then the two high legs must go to opposite phases. If you hook both to the same phase, you will have no power to the controller. Equipment that operates on 240 VAC does not have a neutral leg unless there is also separate 120 VAC devices on the same piece of equipment (example: built-in lights). Almost everything with a metal exterior must be connected to the building ground. Ground is not a current carrying conductor and the ground on a piece of equipment connects only to the metal structure and not to any part of the electrical or electronic circuitry within.

I am not familiar with the particulars of Nova DVR lathes, but some low power (1 HP or less) electronic inverters operate on 120 VAC only. Industrial controllers are normally designed for only one voltage except that some will operate on either single or three phase power.
 
Actually, it appears that you do not have a problem anyway if you have 240 VAC. Just rewire the breaker and change the receptacle and your 240 VAC will now be 120 VAC. Plug your machine in and get turning.
 
When I switched mine from 110 - 220 I put on a new plug, removed a jumper from the board in the motor and I think we may have rearranged the wires in the motor. There is a brief description of how to do this in the manual. It's about 1 page and I flipped past it about 3 times when I was getting prepared.
 
I have the Nova DVR and it is running on 110 VAC. I have 220 VAC but so far after 3 yrs never seen a need to change it. I was always going to change it but I just never got around to it. I just didn't see the need to after using it a while. I have handled some 15 1/2" pretty out of round wood along with coring and it has handled it just fine.
 
Nooooo! I did not just plug it in and watch it smoke. I did install the 220 line 2 years ago for my other equipment. I have seen other tools run 110 or 220, depending on how you want it to operate, but I never converted any of it. I want to go to 220 because it is my understanding it is easier on the motor when starting, and there is about 1/2hp gain. I was hoping someone here would know the technique. I will get in touch with Technatool. I read the instructions again and did not see anything there...maybe it is just a 110 unit.
 
ed crumbley said:
Nooooo! I did not just plug it in and watch it smoke. I did install the 220 line 2 years ago for my other equipment. I have seen other tools run 110 or 220, depending on how you want it to operate, but I never converted any of it. I want to go to 220 because it is my understanding it is easier on the motor when starting, and there is about 1/2hp gain. I was hoping someone here would know the technique. I will get in touch with Technatool. I read the instructions again and did not see anything there...maybe it is just a 110 unit.
Click to expand...

No, there is nothing to gain. The electronics converts the AC power into DC power and uses a pulse width modulated synthesizer to create an approximation of three phase AC power that functionally is equivalent except that now the frequency can be changed to control motor speed. Regardless of the supply voltage, the electronics convert it from single phase to three phase at the proper voltage needed for motor operation ... and it is the same whether running from 120 VAC or 240 VAC.

Concerning the difference in start up, that only applies to capacitor-start single phase motors which is not what your lathe uses. The difference in start up between 120 VAC operation and 240 VAC operation for capacitor-start single phase motors is trivial. The start winding is engaged for only a fraction of a second to get the motor started spinning in the right direction and close to operating speed before the centrifugal switch disengages it. The motor is designed to work just fine with either voltage across the start winding.

Even if we were talking strictly about simple induction motors without electronic controllers, there is no truth in the purported difference in mechanical output power that one frequently sees on Internet forums.
 
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Nova Ratings

Maybe the idea that there's more power using 220V is from the NOVA literature;

"DVR High Torque Direct Drive
1.75 HP 115v. Single Phase 15 amp supply
2 HP 220v SIngle Phase 15 or 20amp supply"
 
Tom Hamilton said:
Maybe the idea that there's more power using 220V is from the NOVA literature;

"DVR High Torque Direct Drive
1.75 HP 115v. Single Phase 15 amp supply
2 HP 220v SIngle Phase 15 or 20amp supply"
Click to expand...

You are right. I was thinking along the lines of mechanical power output for classical AC induction motors where many people are convinced that 240 VAC gives more power than 120 VAC even though they are the same.

But this is a horse of a different color. In the case of the Nova DVR, the motor behaves a bit differently and is more like a stepper motor than an induction motor. The term variable reluctance is also called switched reluctance, where reluctance is basically a magnetic analogy of electrical resistance.

Earlier designs of variable reluctance motors exhibited two of the characteristics that made early stepper motors designed to deliver torque infamous: high torque ripple at low speed and high noise at most speeds as a result of the torque ripple. Since then, there have been many design improvements to address those shortcomings and the current crop of variable reluctance motors are much improved over the early designs. Because of the electronic control system complexity required for these motors, early controllers were not the greatest and did not provide especially good speed regulation, but they have also been immensely improved with the use of embedded high speed microprocessor controllers.

So why does the Nova lathe use these motors? My guess is for the following reasons:

  • switched reluctance motors are probably the lowest cost industrial motors around because of their very simple design.
  • these motors provide a high power output in a small package.
  • The cost of the microprocessor controllers has come down to where they can compete with the cost of a package that uses a three phase induction motor and electronic variable speed inverter.
  • The beast has been tamed through significant improvements in motor design and more affordable sophisticated embedded microprocessor controllers.
Why don't the other lathe manufacturers use these motors? They may eventually if they become more cost effective than what the other manufacturers are using, but right now that is not yet the case. And high precision speed regulation is not overwhelmingly important for woodturning. Lathe manufacturers are not especially concerned about things like the bulk of larger motors and heavier weight when more weight is what woodturners want for their lathes.
 
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Ed - check with Bill Blasic

Ask Bill to get you onto the Nova Users group and take a look in the file cabinet. There is a nice article by Alan Trout on converting to 220. It details the changes including a jumper change and a switch change. I added the suggestion that one fuses the other side of the line for protection which is standard practice for electrical wiring.
 
I appreciate all the help. Looking around the Nova site, I found the conversion, but problem is, this motor does not match the motor pictured. I will contact Tim Giest for some help.
 
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