Part-winding connection

[elinBG]

Hello,

How is called this connection

I found it on an semi-hermetic compressor it is used for "part-winding start".

How does it work?
Any information on it will be great

http://www.eldvigateli.com

 

[rhatcher]

This appears to be a unique, in my experience, example of a two speed, one winding connection. The 'unique' portion is the presence of the additional winding sections that extend from the center of the traditional delta to comprise the 2U, 2V, and 2W connections.

My guess is that when power is applied to the 1U-V-W connection that the result is a two pole connection and that when power is applied to the 2U-V-W connection that the result is a 6 pole connection. Presumably the 6 pole connection would be energized first for starting and the the 2 pole connection would be energized second for running.

If you can provide a picture of the portion of the schematic that shows the starter as well as the specific rating(s) of the motor for starting and running then the answer to your question may be more apparent.

I hope you find this answer helpful. Please respond with more information.

 

[elinBG]

Hello,

This is the schematic that is on the temrinal cover.

This is the nameplate:

Thanks

http://www.eldvigateli.com

 

[ScottyUK]

I agree with rhatcher's guess. Interesting design - I haven't seen that winding configuration before.

If we get a confirmation of those answers it might be the basis of an interesting interview question for the future, just to test a candidate's ability to apply logic and reasoning to something unfamiliar.

 

[mikekilroy]

If it is 2p & 6p then why does the nameplate list 4p and only 4p? and dual delta windings?

'part winding start' is just normal u/v/w in delta
'direct start' adds another delta across same u/v/w but 60 degrees out of phase....

each regular delta coil has 60 degrees across it for 120 degrees from u to v to w. aAding the 7,8,9 wires puts 180 degrees across each of those coils... wierd.

Being a compressor, I am guessing it runs in the 'partial' mode but somehow the added coils reduce inrush for starting with those phase shifts?[ul]
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http://www.KilroyWasHere<dot>com

 

[elinBG]

It is not a double speed motor.This is for sure

The first photo which I shared (

http://i.imgur.com/tFQ8go8.jpg)

is from completely different source - the book "Winding technique of electric motors" by Neven Srb. But unfortunately there is only this schema and nothing explained Except that this is a kind of "part-winding start"

http://www.eldvigateli.com

 

[elinBG]

Sorry!!! checked again, this schema is given exactly in the "Pole-changeable windings" section of Neven Srb's book!

So it is very possible that @rhatcher is right!

Tomorrow the motor will be cutted-off and winding striped out, I will try to draw the winding diagram.
And I will appreciate if someone who can better read the copeland diagram to try to explain how exactly this thing works.

For now it is a "part-winding, pole-changable" motor, correct?

http://www.eldvigateli.com

 

[elinBG]

It looks a lot like this (delta/double star) :

http://www.nzdl.org/gsdlmod?e=d-000...cl=CL2.1&d=HASH01693eebdf3891bea95c4ae7.7.4.2

But the K2, closing the star is missing?

​

http://www.eldvigateli.com

 

[mikekilroy]

dont think that is same thing - missing the extra 3 windings...

googling found same nameplate here:

http://galeria.vulka.es/foto/dwm-co...rio-semi-hermetico-datos-tecnicos_223908.html

http://www.KilroyWasHere<dot>com

 

[mikekilroy]

you probably want to google:

copeland dwm motor

lots of info.....

http://www.KilroyWasHere<dot>com

 

[mikekilroy]

http://www.onninen.com/sweden/produkter/onnline/Documents/Semi-hermetiska+kompressorer.pdf

http://www.KilroyWasHere<dot>com

 

[mikekilroy]

that didnt work.... dont know how to imbed small pix. page 7 of last doc says the paratwinding is optional to reduce starting current.

http://www.KilroyWasHere<dot>com

 

[starkopete]

Hi,
I haven't had time to verify it but I'm pretty sure I've seen that connection on a dual voltage 230/460 volt delta connected motor. The connection that you show was used to run the motor on a 575 volt circuit. 1, 2, 3, were lines, 10, 8, 5 were together as were 11, 9, 6, and finally 4, 7, 12. If you draw it out I think you'll see it looks like what you have above.

Thanks

 

[Motorwinder]

That's a 2 delta PWS. According to the name plate and schematic.

Here is the connection diagram to rewind this motor.

 

[elinBG]

Thank you very much @Motorwinder!

One more hint please:
How to read "Coil end No"?
1 is the beginning of the first coil and 2 is the end of the first coil
3 is the beginning of the second coil and 4 is the end of the second coil
5 is the beginning of the third coil and 6 is the end of the third coil
...and so on...

Is this correct?

http://www.eldvigateli.com

 

[elinBG]

Like this?

http://www.eldvigateli.com

 

[Motorwinder]

Each number represents a group start and finish.

Glad I could help.

 

[Motorwinder]

This might help

Regards

 

[elinBG]

Today we started to open the connection of the motor. The strange thing which is different from the first picture which @MotorWinder showed (4 pole, Delta connected, Part winding, Adjacent Pole, 2 Circuit), is that there are connections with 3 leads.
The other strange thing in this point (where 3 leaads are connected together) is that one of the leads are with 6 wires, the other two leads are with 3 wires
Please check the photo bellow

http://www.eldvigateli.com

 

[ScottyUK]

That would possibly make sense: the winding connected to terminals 7,8,9 sees full line current, so that would be six strands. The other two windings carry lower current and are wound with three strands, e.g. the current entering at terminal 7 splits between the windings connected to terminals 2 and 3.