Wye start Delta Run

[Tim_Nelson]

This is the second time Im trying this because I did nt see my post come up.If you have a 3 phase 208 service,and a motor with a schematic,one chiose wye start the other Delta run. Which one should you connect to,it seems a bit misleading.

 

[augie47]

The two (service type and motor connections) are unrelated.

This site might help you with your motor connections:
http://www.google.com/search?q=wye+...gSok4D4CA&sqi=2&ved=0CDQQsAQ&biw=1280&bih=826

 

[jumper]

Tim,

Welcome to the MH forum!

Patience please, you are new so your initial posts are monitored/moderated before approval per forum rules here.

 

[Tim_Nelson]

Jumper

Jumper

Yeh I was trying to find a delete or edit option wneh I saw them come up, only thing I could find was close thread which Ive done.

 

[jumper]

You need not do anything more, we gotcha you covered.

 

[augie47]

Did my link help or do you need additioanl info ??

 

[Tim_Nelson]

augie47

augie47

The two (service type and motor connections) are unrelated.

This site might help you with your motor connections:
http://www.google.com/search?q=wye+...gSok4D4CA&sqi=2&ved=0CDQQsAQ&biw=1280&bih=826

Well thanks for your time my friend but all I saw on the link was photos of more schematics However I did find this http://us.yhs4.search.yahoo.com/r/_.../us-electrical-motors/wye_start_delta_run.pdf

Which says you need a special capacitor for the Wye Start connection. That is not something I saw on the motor schematic or any other. But it makes interesting reading if anyone is curious. Thanks again for you time, respects.

 

[ActionDave]

This is the second time Im trying this because I did nt see my post come up.If you have a 3 phase 208 service,and a motor with a schematic,one chiose wye start the other Delta run. Which one should you connect to,it seems a bit misleading.

Can you describe a bit more what you are working on.

What is the motor for, what is the HP? I'm thinking you may just need to hook the motor up for 208V and not need the special starter. You would also need a 12 lead motor.

 

[Tim_Nelson]

ActionDave

ActionDave

Well I found my answers in the link I posted that has a PDF attached to it. But what its about is a 25hp 3 phase motor on a wye service ,The motor has a Wye start Delta run connection. And it seems the connection diagram/schematic ,has nothing to do with the service type, wye or delta,as you would find on a smaller motor.I do have a 12 lead motor.Look at the link regarding the capasitor.Anyway all is well thanks.

 

[kwired]

If you are controlling the motor with simple across the line starting method, you connect it according to the "run" diagram. If you have a situation where the POCO wants you to start this motor with starting methods that will reduce the starting surge then you either need soft starter, VFD, part winding start controller, or wye - delta controller. It sounds like you have a motor designed to connect to wye - delta controller. Such motors will still start on full voltage across the line - but the type of driven load or the POCO may help determine if wye-delta starting is necessary. But often times many POCO do not require any special starting methods for a 25 hp motor, you usually have to get into the 50 or 100 HP range before they start to get concerned about your starting methods.

 

[don_resqcapt19]

... And it seems the connection diagram/schematic ,has nothing to do with the service type, wye or delta,...

That is correct, the wye start, delta run connections have nothing to do with the power supply system. You just need a power supply system of the correct voltage, the fact that it is either wye or delta does not make any difference. In this case those term apply to how you connect the 12 leads at the motor.

 

[infinity]

Well I found my answers in the link I posted that has a PDF attached to it. But what its about is a 25hp 3 phase motor on a wye service ,The motor has a Wye start Delta run connection. And it seems the connection diagram/schematic ,has nothing to do with the service type, wye or delta,as you would find on a smaller motor.I do have a 12 lead motor.Look at the link regarding the capasitor.Anyway all is well thanks.

What kind of starter do you have?

 

[kwired]

Well thanks for your time my friend but all I saw on the link was photos of more schematics However I did find this http://us.yhs4.search.yahoo.com/r/_.../us-electrical-motors/wye_start_delta_run.pdf

Which says you need a special capacitor for the Wye Start connection. That is not something I saw on the motor schematic or any other. But it makes interesting reading if anyone is curious. Thanks again for you time, respects.

I think that the information in the link answers your question pretty well. I think you probably meant to say you need a special "contactor" instead of "capacitor". There is no capacitor involved in the wye-delta starting scheme.

 

[GoldDigger]

I think that the information in the link answers your question pretty well. I think you probably meant to say you need a special "contactor" instead of "capacitor". There is no capacitor involved in the wye-delta starting scheme.

But there are a whole lot of little bits in the diagram of the motor on that page that look like capacitors and are not labelled. :angel:

 

[hurk27]

Well thanks for your time my friend but all I saw on the link was photos of more schematics However I did find this http://us.yhs4.search.yahoo.com/r/_.../us-electrical-motors/wye_start_delta_run.pdf

Which says you need a special capacitor for the Wye Start connection. That is not something I saw on the motor schematic or any other. But it makes interesting reading if anyone is curious. Thanks again for you time, respects.

There is nothing in that PDF says anything about a capacitor, if you are referring to the set of contacts labeled S those are two normally close contacts on M2 that open when M2 is energized, they are used to connect the 10,11,12 ends of the winding together to form a WYE when M2 is not energized, some reduced voltage starters (which is what this is called) have these contacts on the run contactor or as a separate two pole normally closed contactor.

The reason its called a low voltage start is each individual winding is rated 230 volts, when connected in a WYE they will see 1.732 volts less then 230, when each pole is connected in series then each pole is rated for 460 volts, but when wired in a WYE each individual winding will see 138.57 volts with a 240 volt supply or in series they will see 277.14 volts with a 480 volt supply.

If you look at the truth chart below each starter diagram you will see the S contacts as open when in run mode, these motors do not have to be run with a WYE start contactor, you can wire the motor as a delta start and run by following the connection diagram for just the run side using either high (480 volts) or low (240 volts) connection, it will start like any 9 lead 3-phase motor with full torque that a normal motor would have of its size.

When wired as accross the line start 12-1 will always connect to L1, 10-2 will always connect to L2, and 11-3 will always connect to L3, for either high or low voltage, then follow the normal 9 lead wiring, for high (480v) connection 7-4, 8-5, 9-6 cap off as such, 12-1-L1, 10-2-L2, 11-3-L3, for low voltage (240v) 7-6-12-1-L1, 8-4-10-2-L2, 9-5-11-3-L3.

This will let you run the motor just like any delta 3-phase motor without a WYE start contactor.

 

[kwired]

There is nothing in that PDF says anything about a capacitor, if you are referring to the set of contacts labeled S those are two normally close contacts on M2 that open when M2 is energized, they are used to connect the 10,11,12 ends of the winding together to form a WYE when M2 is not energized, some reduced voltage starters (which is what this is called) have these contacts on the run contactor or as a separate two pole normally closed contactor.

The reason its called a low voltage start is each individual winding is rated 230 volts, when connected in a WYE they will see 1.732 volts less then 230, when each pole is connected in series then each pole is rated for 460 volts, but when wired in a WYE each individual winding will see 138.57 volts with a 240 volt supply or in series they will see 277.14 volts with a 480 volt supply.

If you look at the truth chart below each starter diagram you will see the S contacts as open when in run mode, these motors do not have to be run with a WYE start contactor, you can wire the motor as a delta start and run by following the connection diagram for just the run side using either high (480 volts) or low (240 volts) connection, it will start like any 9 lead 3-phase motor with full torque that a normal motor would have of its size.

When wired as accross the line start 12-1 will always connect to L1, 10-2 will always connect to L2, and 11-3 will always connect to L3, for either high or low voltage, then follow the normal 9 lead wiring, for high (480v) connection 7-4, 8-5, 9-6 cap off as such, 12-1-L1, 10-2-L2, 11-3-L3, for low voltage (240v) 7-6-12-1-L1, 8-4-10-2-L2, 9-5-11-3-L3.

This will let you run the motor just like any delta 3-phase motor without a WYE start contactor.

Only problem I have with your explanation here is that 1.732 volts less than 230 is not 138.57 it is 228.268 At least I don't think they have changed the addition and subtraction tables lately.

 

[ActionDave]

But there are a whole lot of little bits in the diagram of the motor on that page that look like capacitors and are not labelled. :angel:

I got it.

 

[ActionDave]

What kind of starter do you have?

That's where we are at now. Hope the OP comes back.

 

[hurk27]

Only problem I have with your explanation here is that 1.732 volts less than 230 is not 138.57 it is 228.268 At least I don't think they have changed the addition and subtraction tables lately.

No it's not, 230 volts is the rating of the windings, standard NEMA motor voltage rating just as 460v is, the 1.732 is off the voltage that would normally feed the motor 240 volts or 480 volts, but I see he has 208 volts so take 208/1.732 to get what the windings will see or 120 volts across each winding, which I'm not so sure a 12 lead motor should be WYE started on a 208 volt system, as the motor might not have enough torque to start? but should run find as a across the line start motor if its not a high torque application.

 

[kwired]

No it's not, 230 volts is the rating of the windings, standard NEMA motor voltage rating just as 460v is, the 1.732 is off the voltage that would normally feed the motor 240 volts or 480 volts, but I see he has 208 volts so take 208/1.732 to get what the windings will see or 120 volts across each winding, which I'm not so sure a 12 lead motor should be WYE started on a 208 volt system, as the motor might not have enough torque to start? but should run find as a across the line start motor if its not a high torque application.

You are too serious man.

You said:

when connected in a WYE they will see 1.732 volts less then 230

but later said they will see 138.57.

I said (in other words): 230 - 1.732 = 228.268.:thumbsup: