12 lead wye start/delta run motor

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nullsig

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Louisville KY
For a 12 lead motor there are four potential configurations:

Low voltage delta
Low voltage wye
High voltage wye
High voltage delta

What's the operational difference between high voltage wye and high voltage delta?
 
Besoeker

Besoeker

Senior Member
Location
UK
nullsig said:
For a 12 lead motor there are four potential configurations:

Low voltage delta
Low voltage wye
High voltage wye
High voltage delta

What's the operational difference between high voltage wye and high voltage delta?
Click to expand...
In delta the motor windings will have a greater voltage across them.
 
I

Ingenieur

Senior Member
Location
Earth
visualize it
l-l v across 1 (delta) coil or 2 (wye)
Z of each coil is the same (same motor in this case)
so the d (with lower Z) will flow more i, hence more torque

it's a method of reduced current starting
 
Jraef

Jraef

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Electrical Engineer
ActionDave said:
It's a way to lower starting current by about thirty percent since you are putting the motor windings in series is a rough way to explain it, but torque is also lowered so you switch to delta for full power.
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This is how they are typically used here in North America. Overseas, they also use them as per what Besoeker said, because for everyone else, the difference between a LV and HV supply is the same ratio, 1.732 (the square root of 3). So for them, 400V is connected in Wye (they call it Star), and if you have a 230V supply, you connect it in Delta.

But our 230/460V system here doesn’t work that way, so the only time we use Wye and Delta connections is when doing a form of “reduced voltage starting” as Action Dave indicated.

If you are starting it Across-the-Line or with a Soft Starter or a VFD, you will use Delta connections.
 
Besoeker

Besoeker

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UK
Jraef said:
This is how they are typically used here in North America. Overseas, they also use them as per what Besoeker said, because for everyone else, the difference between a LV and HV supply is the same ratio, 1.732 (the square root of 3). So for them, 400V is connected in Wye (they call it Star), and if you have a 230V supply, you connect it in Delta.
Click to expand...
From my experience here 400V is normally connected in delta. No 230V 3-phase. Star is used with a star delta starter. As I'm sure you know my experience is mostly in the field of variable speed drives but, now and again, in a composite suite with a dozen or so VSDs there may be one fixed speed section requiring a star delta.

I know how they work but it's usually under the radar for me.
 
Sahib

Sahib

Senior Member
Location
India
nullsig said:
For a 12 lead motor there are four potential configurations:

Low voltage delta
Low voltage wye
High voltage wye
High voltage delta

What's the operational difference between high voltage wye and high voltage delta?
Click to expand...
Only for a short time on high voltage wye and continuously on high voltage delta. Most probably the application is in fire pump.
 
G

GoldDigger

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Sahib said:
During start of an induction motor, high voltage Y and that is for a short time. Then for normal running, high voltage delta and that is continuous till motor is switched off.
Click to expand...

The original reference (question) was on the effect of choosing wye or delta motor winding connection with the assumption that the voltage would be changed as necessary to match motor operating conditions.
Your reference only affects applying a fixed voltage to either a wye or a delta connection of the same windings of a motor, as used in soft starting.
 
Sahib

Sahib

Senior Member
Location
India
GoldDigger said:
The original reference (question) was on the effect of choosing wye or delta motor winding connection with the assumption that the voltage would be changed as necessary to match motor operating conditions.
Your reference only affects applying a fixed voltage to either a wye or a delta connection of the same windings of a motor, as used in soft starting.
Click to expand...
Really?! 12 lead motor with high voltage wye start and high voltage delta run is used in fire pump applications. Your application refers to?
 
Besoeker

Besoeker

Senior Member
Location
UK
Sahib said:
During start of an induction motor, high voltage Y and that is for a short time. Then for normal running, high voltage delta and that is continuous till motor is switched off.
Click to expand...
Yes, I did mention that I know how they work.
My question related to this:
"Most probably the application is in fire pump."
Why do you think that?
 
R

retirede

Senior Member
Location
Illinois
Besoeker said:
Yes, I did mention that I know how they work.
My question related to this:
"Most probably the application is in fire pump."
Why do you think that?
Click to expand...

Agreed - before electronic soft starters' cost came down to make them go mainstream, Y-D was the common choice for reduced voltage starting regardless of application.

With a 12 lead motor, whether you used the high or low voltage connections was simply determined by the voltage available.
 
Sahib

Sahib

Senior Member
Location
India
A 12 lead induction motor such as from Baldors for wye delta operation would be damaged if operated continuously in wye.
 
Besoeker

Besoeker

Senior Member
Location
UK
Sahib said:
Because I followed the adage "While in Rome, be a Roman".:)
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Do as the Romans do. But I don't think the Romans had cage induction motors when Hadrian built his wall...........:D
Slightly more seriously, cage motors are the most ubiquitous rotating electrical machines above a few kW and probably with the most diverse applications. Fire pumps being just one of the many.
The 12-lead arrangement gives flexibility of configurations.

But the original question was answered aeons ago.
 
Sahib

Sahib

Senior Member
Location
India
Besoeker said:
Do as the Romans do. But I don't think the Romans had cage induction motors when Hadrian built his wall...........:D
Slightly more seriously, cage motors are the most ubiquitous rotating electrical machines above a few kW and probably with the most diverse applications. Fire pumps being just one of the many.
The 12-lead arrangement gives flexibility of configurations.

But the original question was answered aeons ago.
Click to expand...
In US 12 lead motor with wye delta starting is sparingly used unlike in Europe. The application is UL listed motor in fire pumps. The application where star connected 12 lead motor continuously in operation?
 
Besoeker

Besoeker

Senior Member
Location
UK
Sahib said:
In US 12 lead motor with wye delta starting is sparingly used unlike in Europe. The application is UL listed motor in fire pumps. The application where star connected 12 lead motor continuously in operation?
Click to expand...
690V in my experience.
 
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