Thread: Clarifying 3ph Motor connections

Originally Posted by Oldneweng

Terminal block cover. Terrible picture. Shiny silver sticker and I think the camera had trouble focussing. It is at least readable.

Attachment 298683

That connection diagram above is THE most useful thing posted so far.

If it was me I would connect up the VFD to the delta configuration and see what RPM you get.

Try "& # 8710;"
minus the quotes and the spaces.
∆

Stuart

Hi Dean,

I wonder if 4 pole double delta would work with that motor?

I'll draw a picture, but looking at the terminals, I think it's just linking 1U, 2V and 1W,2U and 1V 2W to make two parallel delta 4 pole 240V 3 Phase


MotorWiring.jpg

Regards
Ray

Originally Posted by .RC.

If it was Qld and I was to have a guess, I would guess $86 456.32

From my understanding if you added another nought it probably still would not cover it. We are talking about running full 3 pH overhead cables at least 5km. Currently only SWER line (Single Wire Earth Return for those who don't know). The existing poles would probably not handle it. About 15 years ago we were quoted about $1500 per pole for single ph in SA.

Dean

Originally Posted by BobL

That connection diagram above is THE most useful thing posted so far.

If it was me I would connect up the VFD to the delta configuration and see what RPM you get.

Worth a try Bob. You mentioned this in Post #3. Oops. Sorry about that.

Dean

Originally Posted by Timless Timber

For PC on forum it should be

& Delta ; (without the spaces).

M = Δ T

Or NOT!

I think its possible that the particular forum itself has to have HTML scripting enabled by the mods for the codes to work....

Coz that exact script renders a Delta symbol on this forum in this thread

http://www.woodworkforums.com/f137/n...73/index2.html

But not here in this forum go figure!

I have found that Alt-30 gives ▲. 30 must be typed from the Num Keyboard like all ascii codes. Alt-190 gives ¥. Is that useful? Reminds me of playing with .bat files back at TAFE.

Stuart.

What is it I am missing here. If I type "& # 8710;" minus the quotes and the spaces. I get ∆. If I hold down Alt and type it I get ♠. However if I do it in Word I get ∆ . Are you using the advanced editor?

Mike.

The nearest dairy farm is about 18km away and now that I think of it I think there is an electricity station thingy near there.

The motor is mounted at the bottom of the casting in a section that has enough room but not much more. I would guess any standard sized motor would fit in. Not much room for your hands tho!

Ray.

I have no idea on that. May be a question for that elusive expert.

Dean

▲...not quite right (ALT 30)

Rays logic seems right to me, one of the motors i tried on the Mars was wired in Double Y and i had to wire it in double ∆ It worked fine but was not of much use as it was 2 pole.

The good thing about using a VFD is that if something is wrong you will not cook the motor, the VFD will sense the problem and go into a "protect mode" of sorts.

Cheers,
Ew

Originally Posted by Ueee

The good thing about using a VFD is that if something is wrong you will not cook the motor, the VFD will sense the problem and go into a "protect mode" of sorts.

This sort of happened to me when I was setting up my DP VFD setup. I forgot to set the max freq on the VFD to something sensible and the whole shebang tried to get up to the VFD max of 400 Hz. At somewhere less than 200Hz the whole thing shut down. I Meggered the motor - still ok. Reset the max Hz to 120 and tried it again and it has been running for about 9 months now without problems.
Hz

My mill and lathe are both 7.5hp and are running 240v 3 phase from a 10 hp vfd that is fed with single phase. I will explain what ive done and maybe it will help you.

My research when i was putting this together was that the vsd needs to be oversized if you are feeding it single phase... I think this is to account for the higher current on the input side which will be running through one leg of the bridge rectifier. Mines hardwired to a 40a circuit but ive never had it draw more than about 18a, but i dont push things very hard. I would say the vfd you have will be fine if you are happy to limit the power and have a longish start ramp time. I would definitely recommend an ammeter on the supply to the vfd so you know whats happening... I have a combined ammeter voltmeter that was less than 10 bucks on ebay but seems to work great.

My lathe motor was dual voltage so it was a snap to connect. It wasnt until i looked for another motor like this for my mill that i realised how rare it is. For my mill i ended up pulling the motor apart, splitting each of the windings groups so there was two groups of coils in parallel, which converted it to 240v delta. In the end it wasnt too difficult and certainly was worth it compared to the $800 i was quoted to get it rewound professionally. The hardest bit is untieing the end wiring and separating it because its all stuck together with varnish so you need to be careful not to damage it. Once its all apart i numbered each of the stator slots and traced each of the coils and made a drawing. Once i worked out the middle point of each phase group i cut the link wire between coils and silver soldered new leads on. The extra leads are labelled and run to the junction box so i had 12 leads instead of the original 6. These are terminated to parallel the 2 groups of coils for each phase. Then the stator end wiring is retied and spray laquered to bond it before the motor is reassembled.

I would suggest pulling the motor apart to have a look and reading some books to get an understanding of how it all works then decide if you want to have a go at modifying it. I found and downloaded a few useful books i can share if youre interested.

Originally Posted by .RC.

If it was Qld and I was to have a guess, I would guess $86 456.32

RC

You sir, are an optimist, or things are much cheaper 900 Ks down the track! About 18 years ago I got a "ballpark" quote from the then Cairns Regional Electricity Board of "in excess of $20000" to run 3 phase from the transformer about 100m up the road to the property boundary. The property directly opposite me already has a 3 phase supply to the shed from the same transformer. I would then have had to run an underground cable 100m to the main board at the house, then a further 20m to the sub board in the shed.

I am still running everything single phase.

Frank.

[QUOTE=Oldneweng:

Photos not good due to the location of the plate. Mostly get blurs. Info as follows.

THREE PHASE MULTISPEED POLE CHANGING INDUCTION MOTORS. [COLOR=#0000ff](Heading on top of data section. May be just a company description. Chinese writing above it. Company name?)
[/COLOR]
TYPE D132M-8/4 (Poles?)_____ No. 1583________ --------KW
3.75/7.5 HP ________________ 730/1446r/min ___CLASS B S1 "B" may be symbol?
CONN ∆/YY ________________ 50 Hz ___________DATE -------- I gave up looking for the delta symbol. I have forgotten the ANSI Codes. I copied BobL's. What did you use Bob? "-----" Blank.

This is the best pic I could get.

Attachment 298647

That info suggests that the motor has two power ratings "3.75/7.5 HP" one set of windings is in delta and the other is star. I think that it won't do the VFD much good connecting it to the higher power windings though it shouldn't have any problems with 3.75 HP. I would think that this motor has been used on something that required a slow speed start and then switched to the high speed windings.

I don't have sufficient experience/knowledge to say which set of windings is which. A guess would be that the higher resistance windings would be the slower speed ones since those would be the 8 pole windings.

HTH.

Originally Posted by BobL

It depends on what type of computer you are using (I'm using a Mac so it's "Option J"
With a PC, to get the Greek letters it's usually "Alt and then a number" but I don't think there is one for upper case delta.
Maybe a PC user can pitch in here.

Did you look on the underneath of the terminal block cover.
A couple of motors I have show the ∆ - Y conversion either stamped into the metal or on a piece of paper glued in place - like this.
PLEASE NOTE: DO NOT USE THIS CONNECTION PATTERN AS BEING APPLICABLE TO YOUR MOTOR

As far as I am aware the motor that he has is not re-wireable for star/delta conversion. one set of terminals is star the other is delta.

The motor looks like it is a 6 pole two speed winding with the low speed in delta and the high speed in star/star, I attach a pdf that shows this.
You could try wiring in the delta mode as it would be at 3.8kW rating and your VSD is rated at 4kW from what I read, you would be looking at a current draw of between 25 to 32 amps.
I hope this is of use to you.

Regard,
Keith_W.

Originally Posted by Oldneweng

Good idea. Any suggestions about how much that would cost? Base it on a distance of 5km for now but to be honest I have no idea where it would have to come from. Maybe I should get a quote as soon as I can!

A 3ph generator would be a tiny fraction of that cost tho!

Dean

Cost me a bit over $8000 to get 3 phase run a bit over 250m. $4K for my contribution to the transformer and $1500 a pole to replace the old 6m steel poles with 8m steel poles of larger section. So not cheap.

I know a bloke in Donald that might be able to help you out if you want to go that far. PM me for his details, he looks after the electrical stuff etc for a couple factories and I'm pretty sure he has some motors lying around as spares, might have a 5 HP unit. Very nice man to deal with and a wealth of information. Also I may be interested in buying that motor off of you if you can't use it yourself......

FWIW I'm not sure what you're referring to when you say CY - is that a Monarch CY lathe or some other manufacturer? Because I have a Monarch CY and it does have a 7.5HP 3 phase motor installed but it's only single speed 1440 RPM and I've never needed anything more, however the speeds go from 13 RPM to 480 RPM so a bit slow for small work (but perfect for decent cuts). Your motor is 4 pole/8 pole so I'd expect your geared speed range to be somewhat less with the 2 speed motor making up the difference. If so then I'd advise getting the biggest single phase VFD and motor combination you can because you're going to lose serious performance running even a 5 HP motor at say 30 Hz to get the speed down.

PDW

Originally Posted by PDW

FWIW I'm not sure what you're referring to when you say CY - is that a Monarch CY lathe or some other manufacturer?

It is a CY series lathe made by Yunnan Machine Tool Works.. YUNNAN CY GROUP CO., LTD