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Can this motor be wired for 240v?

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Ropata

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#1
Hi guy's,

As per the title, is there an easy way to tell if this WEG branded motor can be wired for 240 volt? I have an old VFD that outputs 240 3 phase only.

20171005_184622.jpg 20171005_184635.jpg 20171005_184756.jpg
 

MozamPete

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#2
Should be able to. It appears to be 400V star connected so if you reconfigure it as a delta motor it would need 240V. Would pull a bit extra current if fully loaded but that should be OK.

All six winding ends seem to be taken out to the terminal box (looks like the top two rows in the photo) so you would just remove the shorting bar from the top three and then reconnect something like this

upload_2017-10-5_8-56-40.png


That is assuming each winding is connected to terminals that are in line. You would need to do a continuity check as they sometime do the step internally so that the delta links are just vertical (ie one winding will internally connect to say the top right terminal and the bottom middle)
 
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Ropata

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#3
Thanks Peter. Can any damage be done if I do it wrong first time or will the motor just spin the wrong way?
 

MozamPete

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#4
You say your VFD outputs 240V 3 phase. Just check that that is 240V between two phase, not phase to earth. Equipment running on 240V between phases would be unusual in NZ, the normal household supply is 230V phase to earth so already 380V phase to phase.

You may not need to reconfigure the motor.
 

Ropata

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#5
Sorry Peter, this is all Greek to me. I might take a better look at both the motor and the VFD in the morning and report back. We run on 240v single phase multiple earth neutral. I think our system is identical to China.

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MozamPete

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#6
I'm actually a kiwi - just live/work in Africa. That's why I started to think a 240V 3 phase VSD would be a strange thing to have there.
 

jim18655

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#8
Motors with terminals like that usually are connected in straight lines so you can just re-position the links.
 

British Steel

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#9
Should be able to. It appears to be 400V star connected so if you reconfigure it as a delta motor it would need 240V. Would pull a bit extra current if fully loaded but that should be OK.

All six winding ends seem to be taken out to the terminal box (looks like the top two rows in the photo) so you would just remove the shorting bar from the top three and then reconnect something like this

View attachment 243427


That is assuming each winding is connected to terminals that are in line. You would need to do a continuity check as they sometime do the step internally so that the delta links are just vertical (ie one winding will internally connect to say the top right terminal and the bottom middle)

Even easier than that, most 3-phase dual voltage motors are set up with the winding ends already staggered, so three short, straight links and you have delta... With the links off, there will be open circuit from one to the other "vertically" and as Pete says, from one of each vertical pair to the opposite of the next pair.

The pair at the bottom of the pic may be for a thermal switch, to disconnect (via a contactor) if the motor overheats, or even a magnetically operated brake (hard to tell without a pic of the other end of the motor).

Dave H. (the other one)
 

Ropata

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#10
Even easier than that, most 3-phase dual voltage motors are set up with the winding ends already staggered, so three short, straight links and you have delta... With the links off, there will be open circuit from one to the other "vertically" and as Pete says, from one of each vertical pair to the opposite of the next pair.

The pair at the bottom of the pic may be for a thermal switch, to disconnect (via a contactor) if the motor overheats, or even a magnetically operated brake (hard to tell without a pic of the other end of the motor).

Dave H. (the other one)
Great. I'll do a video after work of a continuity check of all connections. Should I pull off the short bars so all terminals are isolated first? the motor is off an old wood working machine, maybe a thicknesser.
 

British Steel

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#12
Definitely DON'T use that as a guide, it's American 9-wire, used in America and nowhere else - you have a 6-wire star-delta rest-of-the-world motor!
There's a great big clue on the motor plate, the upside-down Y telling you it's in star configuration *as the links are currently placed*

Dave H. (the other one)
 

Ropata

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#15
So from all the research I've been doing, Could it be possible this was wired in 24o in the first photo?
 

British Steel

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#16
Perfect buzzing out of the terminals! - the winding resistances match too, which is a good sign :)

The bottom two are most likely the thermal switch - if you suspect you'll be working it very hard you can put those in series with the fwd/rev switching line and they'll power the motor off if it overheats. (In the loop from the DCM common terminal to the fwd/rev switches).

The other six *were* linked for delta, the higher (415v) voltage configuration, to wire for 240v link them in pairs: middle left to top left, middle middle to top middle, middle right to top right, attach 3-phase 240v from your VFD outputs (U, V, W) to middle left, middle and right, Robert is your parent's sibling!

If it rotates the wrong way either swap two of the 3 phases (at VFD or motor, doesn't matter where) or swap the VFD forward and reverse inputs, probably easier on the motor once everything else is wired?

Dave H. (the other one)
 

Ropata

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#17
Perfect buzzing out of the terminals! - the winding resistances match too, which is a good sign :)

The bottom two are most likely the thermal switch - if you suspect you'll be working it very hard you can put those in series with the fwd/rev switching line and they'll power the motor off if it overheats. (In the loop from the DCM common terminal to the fwd/rev switches).

The other six *were* linked for delta, the higher (415v) voltage configuration, to wire for 240v link them in pairs: middle left to top left, middle middle to top middle, middle right to top right, attach 3-phase 240v from your VFD outputs (U, V, W) to middle left, middle and right, Robert is your parent's sibling!

If it rotates the wrong way either swap two of the 3 phases (at VFD or motor, doesn't matter where) or swap the VFD forward and reverse inputs, probably easier on the motor once everything else is wired?

Dave H. (the other one)
Thanks Dave, you sound confident! Is there any this could turn to scrap if we're wrong? So like the picture below?



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British Steel

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#19
Exactly like that! The other two can be useful (temperature switch, black and white on the bottom terminals) particularly if you'll be running the motor under speed, when the fan may not give enough cooling - better to have it cut out than burn out! On my lathe (which I run down at 5Hz occasionally) I've fitted a big axial fan blowing through the built-in fan and programmed the VFD to switch it OFF above 30Hz - which seems to work pretty well do far...

Dave H. (the other one)
 

killswitch505

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#20
Oh damn I'm super sorry I didn't read the whole thread. I'm on a few electrical FB groups and electrical forums it's always the same "The leads aren't labeled" post heck I have that pic saved along with a 12 lead pic I assumed it was typical 9 lead motor again my apologizes
 

jim18655

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#21
The concern I have is that the tag only lists one voltage for the motor. If you look at the diagrams in the link I posted the 6 lead motor can be one voltage wye-delta or dual voltage wye-delta (high-low). Can you post a better picture of the whole tag?
 

British Steel

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#22
Jim, it's labelled as 400v star, delta it'll be 230-240, thats how motors work, except in the USA.
If it was marked 400v delta, it would be 690 or so in star.

Dave H. (the other one)
 

jim18655

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#23
Jim, it's labelled as 400v star, delta it'll be 230-240, thats how motors work, except in the USA.
If it was marked 400v delta, it would be 690 or so in star.

Dave H. (the other one)
Learn something new all the time in this forum. So they don't mark dual voltage motors with both voltages - just the one and you know the other?
 

British Steel

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#24
You have to work out which is what - delta's always the lower voltage, star the higher, and there's the root 3 factor between them - it's easiest to picture it through a bit of basic geometry: a delta has the line voltage on the sides of the triangle, e.g. 240v between phases, if you then rearrange the three sides (the windings) in a 3-pointed star with 240 on each, measuring across the points will be 415v and at the centre where they join, the "star point", will stay at zero - this will (or can, it's not needed) be the Neutral.

Only time this goes out the window is with medium-voltage motors, usually in the 100HP class, where the 3-phase voltage can be anything from 660 - 720v to 3.3 KV - I don't play with those, they're scary!

This is how most of the world distributes power, 220 - 240v (now "harmonised" to 230v +/- 10% in Europe) phase to neutral, 380 - 415v (400v harmonised)phase to phase. The phase to neutral service is in most homes, where it's normally only one phase and limited to 80 - 100 A, 3-phase for commercial and industrial up to about 400A, then for even more you get your own substation transformer down from 3.3 KV or 11 KV to 415/720v, that'll supply quite a bit of power...

Dave H. (the other one)
 

jim18655

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#25
I drew it out before my last post to see how it works and got what you said. I've connected some European motors but it was so long ago I don't remember how it was done. I do remember they were three voltages something like 240 - 480 -560. Some of the electricians on the job were used to connecting for high voltage on US motors and didn't notice high was 560. Needless to say, but those didn't run.
 

Ropata

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#26
I have had some success!
I really can't make sense of the manual and from what I've read on forums, the set ups are pretty similar. Can anyone give me some simple instructions to see if this will work at full power so I can start on actually building the frame for this motor mount set up?
 

British Steel

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#27
I don't know that particular VFD, but *some* parameters you need are@

The most important:
Base frequency 50Hz (this is the point where it'll start delivering full voltage, 240v, to the motor - up to this it'll scale it by the frequency as a fraction to avoid burning the motor out, above it remains at the full 240v - 50Hz for European/rest-of-the-world motors, 60 for American);
Max current (may be labelled I max or similar) - you need to apply the root3 factor to the motor plate full load amps, so 3.3 (on the plate) x 1.73 = 5.7 Amps. there may be a parameter for overload current, which it'll deliver for short bursts e.g. initial start-up, usually the max is 1.5 x max current;
Motor cos or power factor - usually about 0.7 works.

the ones that govern speed:
Min frequency however low you want to go, motor speed scales down with this so e.g. 10Hz will give a fifth the marked RPM (beware of overheating!);
Max frequency - similar to above! I wouldn't go above 100Hz (double rated speed) in the interest of bearings and the motor rotor, centrifugal force etc.!

Good luck, and have fun playing!

Dave H. (the other one)
 
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Ropata

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#28
Awesome Dave, setting the 50hz in pd004 was the key, up and running full power now. I'll go through some other settings so as to not burn it out amongst other things when I get it built. Thanks alot for all your help guys. This forum has been nothing but essential for me while trying to learn.

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British Steel

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#29
If you're going to be running at low frequencies / motor speeds, something like this:

motor cooling scaled.jpg

will keep it cool: Papst 10" fan, cut off and "reworked" bottom of a chemical drum, foam gasket - all anchored to the mounting bolts for the grille over the (open frame) motor air intake - you may want something smaller, the Holbrook's motor is the size of a dustbin!

Dave H. (the other one)
 

Ropata

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#30
If you're going to be running at low frequencies / motor speeds, something like this:

View attachment 243585

will keep it cool: Papst 10" fan, cut off and "reworked" bottom of a chemical drum, foam gasket - all anchored to the mounting bolts for the grille over the (open frame) motor air intake - you may want something smaller, the Holbrook's motor is the size of a dustbin!

Dave H. (the other one)
I shouldn't need on for this grinder build due to the speeds being reasonably high for all the grinding I'll need but will probably need one for the slow rotary welding table coming up next.

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