3 phase motor star delta staring controls

[Chrisday1990]

Hi guys
with the star delta motor starting controls I know you have 3 contractors, the main, the star & then delta. The star contractor is looped out as star configuration at the top but I cannot see how the delta contractor is configured in delta, it just looks like a standard contractor to me? Or does the delta part come from how you configure the 6 lead connection within the motor head?
Finally what is the universal way to configure the 6 leads within in the motor head to up get things spinning clockwise. I.e , main contractor supplies L1- w1 L2- u1 & L3-v1, star delta side w2 U2 v2 ???

 

[SheffSimon]

Main contactor connects L1-U1, L2-V1, L3-W1, delta contactor connects L1-W2, L2-U2, L3-V2, which gives a clockwise phase rotation.

The star contactor connects the other ends of the 3 windings together, the delta contactor connects them to phases so the motor is connected in delta. All done using ordinary contactors with the star and delta mechanically interlocked.

 

[Chrisday1990]

Main contactor connects L1-U1, L2-V1, L3-W1, delta contactor connects L1-W2, L2-U2, L3-V2, which gives a clockwise phase rotation.

The star contactor connects the other ends of the 3 windings together, the delta contactor connects them to phases so the motor is connected in delta. All done using ordinary contactors with the star and delta mechanically interlocked.

thanks for the explanation simon much appreciated, finally the overload would it matter if it's on either the delta contactor or the star.

 

[Chrisday1990]

thanks for the explanation simon much appreciated, finally the overload would it matter if it's on either the delta contactor or the star.

Sorry one more thing, I came across a motor connected main contactor L1-u1 L2-v1 L3-w1 delta side L1- v2 L2- w2 L3-U2 and was running clockwise fine. Would this connection ok in the long run.

 

[Knobhead]

It wouldn’t run otherwise.

 

[Darkwood]

When you say you came across this set-up are you involved in any way with its connecting it up ... if through curiosity then just google it, its explained with diagrams many times over..(unless Tony above is in a rare good mood :redface-- if your involved in this in any way then Ill have to say you shouldn't be messing with this stuff as your questions are very basic and your clearly out of your training and experience area on this one.

There are many things to look out for and different set-ups regarding overload position which will require calculating for the correct setting if say you had it in the delta arrangement....no you don't set it to the motor rated value!

As for changing direction you do not change it at the motor terminals you change it at the common supply to the contactors ..again basic stuff about changing rotation of a 3ph induction motor..

Is this homework???.... I do really hope you are not messing about with this stuff as you are well out of your depth here.

 

[Chrisday1990]

It wouldn’t run otherwise.

Hi Tony
we saw it running today, or maybe I could have noted the connections down wrong

 

[Chrisday1990]

I did think that These must be basic to an industrial sparks,To be honest no experience with motors, just a commercial electrician trying to get into motors, I guess you could call it homework, the company I work for had this motor replaced like 2 times over 2 years so I was just taking an interest, however I would defiantly take your advice on keeping away.

 

[telectrix]

an idea might be for you to scrounge a few old contactors and other bits from work and wire a starter system up (not to be energised) then show it to the head sparks at work. he can then tell you where and if you've gone wrong. when he thinks you've got it right, it can be connected to a supply under supervision and see if it works OK. that's how i learnt a lot.

 

[Darkwood]

I did think that These must be basic to an industrial sparks,To be honest no experience with motors, just a commercial electrician trying to get into motors, I guess you could call it homework, the company I work for had this motor replaced like 2 times over 2 years so I was just taking an interest, however I would defiantly take your advice on keeping away.

Fair enough .. good to see enthusiasm, if the motor has been replaced twice in the last two years it sounds like something is wrong or its unsuitable for the job ... out of interest what does the motor do and what size in Kw or HP are we talking?... A correctly spec'd motor and properly protected should see years of service Electrically but may be subject to premature mechanical wear and tear on bearings etc if not fitted correctly. What happened to the motor before when it went breasts up ?

Ps Id start at the basics with motors and work your way up to star/delta starting... your trying to jump in a few rungs up the ladder which will be confusing without the background of the basics.

 

[Simonslimline]

Do any of you experianced sparks have any recommendations on good books about motors and motor control?

I know the real learning comes from experiance but knowing the theory inside out will also help alot imo. We covered motors and starters at college but I am sure there is lots lots more to learn.

 

[atm84]

When you say you came across this set-up are you involved in any way with its connecting it up ... if through curiosity then just google it, its explained with diagrams many times over..(unless Tony above is in a rare good mood :redface-- if your involved in this in any way then Ill have to say you shouldn't be messing with this stuff as your questions are very basic and your clearly out of your training and experience area on this one.

There are many things to look out for and different set-ups regarding overload position which will require calculating for the correct setting if say you had it in the delta arrangement....no you don't set it to the motor rated value!

As for changing direction you do not change it at the motor terminals you change it at the common supply to the contactors ..again basic stuff about changing rotation of a 3ph induction motor..

Is this homework???.... I do really hope you are not messing about with this stuff as you are well out of your depth here.

How about helping the guy out and building his confidence instead of always putting ppl down, telling them they are out of their depth. Have you never come across something that you were unsure about and tried to seek advice from someone?? Sometimes you only learn by taking on such jobs and getting hands on experience. If you turn up to every difficult job and said 'oh I've never done this before I better leave it to someone else' you would never learn!! Rant over.

 

[Darkwood]

How about helping the guy out and building his confidence instead of always putting ppl down, telling them they are out of their depth. Have you never come across something that you were unsure about and tried to seek advice from someone?? Sometimes you only learn by taking on such jobs and getting hands on experience. If you turn up to every difficult job and said 'oh I've never done this before I better leave it to someone else' you would never learn!! Rant over.

My post posed several questions to which the OP has kindly answeredand thus tailored my response with a positive had you read further on in the thread.

The OP gave a suggestion he was involved with this work in some way and asking a lot of questions regarding it, the nature of the questions implied if he was involved without been overseen then Ill stand by my post and say he would have been out of his depth which can lead to safety issues and big costs.
As the OP has replied to my post explaining he is generally interested in looking into this field I have advised him the best way.

We work in a very dangerous industry that can have massive consequences if you are delving into areas you are not competent in so I will not apologise for been a bit up front with my posts and expressing when someone may be out of there depth...it may be the best advice they ever get.
I have trained several apprentices over the years and one thing is for sure your don't get far if you can't give them a reality check when they need one.. in the long run it could save their lives or an expensive balls up.

As a regular poster atm84 you should know its not my intention to belittleor put anyone down just for the sake of it but when I see a possibility of someone playing with fire, I for one will let them know they will burn their fingers.
I don't get 650+ thanks and over 3400 likes for attacking and belittling members... The OP gave me reason to express my thoughts that way and question what exact role he was playing in this?

My minor rant over :smiley2:

 

[D Skelton]

Do any of you experianced sparks have any recommendations on good books about motors and motor control?

I know the real learning comes from experiance but knowing the theory inside out will also help alot imo. We covered motors and starters at college but I am sure there is lots lots more to learn.

Here, this might help get you started:

http://www.moeller.net/binary/schabu/wiring_man_en.pdf

 

[Knobhead]

When you say you came across this set-up are you involved in any way with its connecting it up ... if through curiosity then just google it, its explained with diagrams many times over..(unless Tony above is in a rare good mood) :redface:

If the OP gets in touch via PM I’ll help him.

You’ve seen the animated drawings DW. They save a lot of written explanation.

 

[Chrisday1990]

How about helping the guy out and building his confidence instead of always putting ppl down, telling them they are out of their depth. Have you never come across something that you were unsure about and tried to seek advice from someone?? Sometimes you only learn by taking on such jobs and getting hands on experience. If you turn up to every difficult job and said 'oh I've never done this before I better leave it to someone else' you would never learn!! Rant over.

Thanks dark wood I share the same philosophy and that's exactly what we are doing, very kind/encouraging words.

 

[PEG]

Darkwoods cautionary message is not without worth...a client of mine decided to do some "real-time" learning on a large 3 PH screw compressor panel,and manually engaged the star and delta contactors simultaneously with alarming consequences. At least he can see now,even if he wanted another go...which he does not! The bill for full rectification was another reminder...

 

[Chrisday1990]

WOW, I would hate to have been that guy he must have felt crap. Yet such an easy and unforgiving mistake to make.

 

[ipf]

Darkwoods cautionary message is not without worth...a client of mine decided to do some "real-time" learning on a large 3 PH screw compressor panel,and manually engaged the star and delta contactors simultaneously with alarming consequences. At least he can see now,even if he wanted another go...which he does not! The bill for full rectification was another reminder...

I can imagine...can be bad enough getting the direction wrong on a 'screw'

 

[Knobhead]

We only had two Y∆ starters on plant. High pressure water pumps bought as a turnkey project.

One of the idiots (management) decided they should be like the rest of the plant where the PLC took control of all drives. So I got lumbered with altering the program. The contractor installing the drives seemed a bit bemused when I told him to rip all the control wiring out other that the power side. All he had to do was connect a 19 core to the various parts and in to one of the I/O racks. I’d had to install yet another volt free 16 way O/P card.

OK so far.
Enter Tony with a thumping hangover, things went badly wrong from then on.
First off, allocate the new cards location, smartarse here though he could do it on the fly. The plant shut down.
I’m not popular at this point

Get the plant up and running.
Start again with the program.
Both pumps were fed off a small CFS sub board with a 600A incomer. So the pumps had to start in sequence. Forgot all about that bit.
Any though of scan sequence went from my mind and I managed to get two networks cutting each others throats, couldn’t see this on the PC so carried blithely on.
So, power up the pumps and toddle off to the control panel.
Press sequence start everything went fine until the pumps started, the lights dimmed. At that point I remember they shouldn’t start together. The supply was holding so let them carry on.
Come the transition point all the lights started pulsing on and off. The Y∆ contactors were going in and out with the PLC scan rate.
I’m even more unpopular

I’m sobering up by now, quick re-gig of the program.
Try again.
Pump 1 tries to start.
It’s gone dark in here!
I’m definitely not popular by now.
The 600A fused supply to the sub board had held. One of the 1200A plant feeder ACB’s had tripped.
Both the Y∆ contactors had just about melted.
Ooopps.

The upshot was.
The contractor got rather a large bill for the repairs.

OK I’m a barsteward, I shifted the blame on to the contractor. The plant worked perfectly after the repairs so it must have been his fault…………..