Star/Delta switch

[solarengineer]

I've searched the board looking for an easy to follow wiring diagram for a star/delta switch..

I have 3 dpdt (double pole double throw) automotive relays and a 9 coil stator.

what im looking for is an easy way to connect the ABC/XYZ connections to the relays.



any help would be greatly appreciated


Thanks
Jamie

[willib]

wind stuff ed's page had just what you are looking for..

http://www.windstuffnow.com

but i cant find it at the moment

[Titantornado]

[powerbuoy]

I just drew this up ... it's getting late and I would recommend to verify these connections before powering it up. Important is that you have to interlock coil supply star and coil supply delta (they cannot be on at the same time!!!)... otherwise ...bang.

Any comment on this drawing is highly appreciated. Currently the only way I see with 3 DPDT relays.

[solarengineer]

Titantornado, the symbols that look like capacitors(2 vertical bars)that have a slash across them, is that the normally closed contact of the relay? and the open pair of vertical bars is the normally open?


Thanks for everyones help!!

Jamie

[Flux]

Yes the contacts with the slash across them are normally closed.

You need 3 pole change over for star delta. You can do it with 2 of your relays.

[hvirtane]

This is a really good discussion. I would like to see the results of using your '3 dpdt (double pole double throw) automotive relays'. If it will work well, it will help also others to build cheaply better machinery. Quite similar arrangements can also be used for dump loads.

- Hannu

[stop4stuff]

I made a star/delta switch block a while back using Lego

This diagram shows the connections for star & delta.

The switches are salvaged from old microwave ovens (door switches), but the connections would be the same for your DPDT relays.

A thought... what would happen if one relay failed?

paul

[Nando]

One should use a 3PDT relay = 3 poles double throw relay.

Reason: protection in case of relay breakdown.

I suggest that multiple relays are not used unless they have a second independent set of contacts to insure all relays are energized and working.

I have an automatic switch over based in output voltage and current, but it is in a PC with problems.

The mill starts in STAR configuration, then once the current is certain value, the relay is energized for DELTA configuration and the circuit needs to take in account the current charge increment/decrement to maintain the configuration in the proper setting.

The main problem is the current detection for configuration setting, for heavy currents I have used the Allegro 75 & 150 Amps current detectors.

Nando.

[solarengineer]

Ok, Here is my DanCAD drawing using Titantornado's picture. I redrew the schematic based on my own understanding.
Here is my drawing, do i have this right? or is my prop going into orbit?

Thanks everyone, and Nando has a great idea to use a 3PDT Relay instead of the way I have it. But if I do have the wiring right then it's easily adapted.

If I do have it wrong, could someone redraw it the way I did? I understand it better that way.

Thanks alot!

BTW the ABC and XYZ are from DanB's red greed and puple(blue) coil diagram

[Titantornado]

Looks good.    I too, would use a three pole, motor contactor with N/C and N/O connections, rather than multiple relays.  Better still, if automatic switchover isn't required, is a manual switch like that described earlier.

[solarengineer]

I think i screwed it up, the ABC are going to the Normally open contacts which are not tied to anything elso so they never get connected together for star....

unless im missing something it looks wrong (

[Flux]

Try it this way may be easier to follow.

[solarengineer]

FLUX!!!!!

I started giggling as soon as i looked at it!! WHAM! I finally got it!!

That couldn't be easier to follow THANK YOU!!!!!!!!



Jamie

[Titantornado]

Your drawing is right on solarengineer.  You have it drawn with N/C contacts for star, which is correct.  

[solarengineer]

Thanks Titantornado!!

[kurt]

http://www.dsgnspec.com/StarDelta.html