Wye/Dela motor

[kalabdel]

Hello guys,

I've noticed on a few motor nameplates ratings that I don't understand. They have three lines:
- ▲/Y 30/400 followed by ratings
- ▲ 276
- Y 480

I understand that a motor can be wired Wye or Delta but the first line I don't get. What does it mean?

Thanks
Kal

 

[jraef]

The first part is missing a digit, it should say 230/400V, you connect it in Delta if you have a 230V supply, connect it in Y if you have 400V (nominal), and these would be 50Hz ratings.

The second set is telling you that if you have 480V 60 Hz, you connect it in Y, but if you connect it in Delta, it would be rated for 277V 3 phase, which doesn't exist so it's superfluous information but can sometimes be useful with VFDs where you need full torque at higher than base speed (outlier issue that takes a long explanation).

 

[GaryS]

Each winding in the motor is 240 V
connected in Delta the windings are in parallel 240 V
connected in Y the windings are in series 480 ( 240 - 240)
that quite common can also be used y delta start connection we don't see that much anymore.

 

[DickDV]

I would expect that this is a six lead motor so there are only three windings. There is no series or parallel. Only wye or delta. Each coil is rated 230V at 50hz and 277V at 60hz. You would not, as jraef states, connect the coils in delta at 60hz since that would require a 277V source. The only practical 60hz connection is wye requiring a 460V source.

At 50hz, a delta connection requires 230V and a wye connection requires 400V for sources. Both of these are common in 50hz territory.

 

[jraef]

Each winding in the motor is 240 V
connected in Delta the windings are in parallel 240 V
connected in Y the windings are in series 480 ( 240 - 240)
that quite common can also be used y delta start connection we don't see that much anymore.

That's how a NEMA dual voltage motor would be made, his is an IEC dual voltage motor, that is the standard configuration for them.

 

[kalabdel]

Thanks everyone. Please see attached picture.
My apologies for not including it earlier.

I had aother look at it and I am guessing the first line is for wiring delta and wye in 50 herz and the following two lines are for 60 herz. Surprised though of the voltages of 400 and 276, does the phase angle change with frequency?
Cheers
Kal

 

[Mara]

(480V / 60Hz) * 50Hz = 400V

(276V / 60Hz) * 50Hz = 230V

Phase angle is always the same in three phase system (120º) or what you mean by phase angle?

 

[Mark Snodgrass]

The difference in the ratings for 50hz versus 60hz is due to the change in inductive reactance. The windings are rated for a certain amount of current. In a motor opposition to current is two main components resistance of the windings and inductive reactance, capacitive reactance is negligible in motors. Inductive reactance is the major contributor in a running motor, as resistance of the windings becomes increasingly smaller to help increase motor efficiency.

Inductive reactance has the formula of:

XL=2[FONT=&quot]πfL

[/FONT]Where f (frequency) is the only thing that changes, thus a lower frequency would provide less inductive reactance. And therefore a lower voltage rating per Ohms Law to get the same current.[FONT=&quot]


[/FONT]

 

[kalabdel]

Excellent Thanks a lot.

Kal