Is the motor 240v delta or wye? Or does it matter??

[1capybara]

We have several motors labelled only "240v 60hz 3-phase"
These motor are made in USA - an industrial floor standing band saw, band sander, dimpling machine, etc.
and name plate doesn't say if thats delta or wye.
I assume the motors are actually 240v delta, since thats a standard voltage in USA.
And so any transformer or frequency converter (I'm in a 50hz country) must specify delta.
Correct? Or how can I be sure what the motor needs?
Now here's a difficulter question:
I also have one motor labelled "480v 60hz 3-phase."
This can be either 480v delta or 277/480 wye.
How can I be sure which it is? Or does it matter?

 

[electricpete]

IF there are only three leads from the motor, then why would it matter whether it is internally wired as delta or wye (it won't change the way you hook it up).


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(2B)+(2B)' ?

 

[LionelHutz]

Motors don't care if the source is wye or delta connected.

 

[jraef]

Apples and oranges.

How the motor coils are connected internally is not at all related to how the supply transformer is connected. If a motor says 240V, that means 240V phase to phase. If you have a 240V 3 phase system, it is 240V phase to phase. That's all you need to know. The phase to ground voltage reference of your supply is relevant to a number of other issues, but the connection to a 3 phase motor is NOT one of them.

The INTERNAL connection of the coils inside of the motor makes a difference ONLY to the motor design engineer, having to do with conductor dimensions, slot depth, and magnetic permeability of the steel.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[waross]

IEC motors often have three windings, one per phase. The windings may be connected in star or in delta.
A typical motor may be suitable for 400 Volts supply when connected in star and for 230 Volts supply when connected in delta.
They may be rated for other voltages but the ratio between the star voltage rating and the delta voltage rating will be √3:1
North American motors typically have six windings, two per phase. Each pair of phase windings may be connected in series for the higher voltage rating or in parallel for the lower voltage rating. The windings are commonly connected in star but there are some motors with an internal delta connection. There are some internal connections between the windings that cannot be changed, and so a delta connected motor must stay a delta connected motor and a star connected motor must remain a star.
The voltage ratio between High Volts and Low Volts is 2:1
But for the purposes of supply, it doesn't matter.
Caution! If you are changing the connections on a NEMA motor from High Volts to Low Volts you must know which it is, star or delta. The High voltage connections are the same for star or delta but the low voltage connections are different.
If there is a connection diagram no problem. If there is no connection diagram you must test the leads.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[zlatkodo]

Need to know how many leads is there: 3, 6, 9 or 12?
For both motors.
Note that "Wye" or "Delta" is a task for winding designer and "Wye" connection is always preferred.
Tech Support in Winding Design