Multi voltage motors

[Lc85]

We have a Weg Motor data sheet that says the voltage is
380-400-415/660-690v 50hz
Motor is 110kw

The clients supply is 400v and motor rated voltage is 400v

So if we connect it in delta we should be fine for 400V?

Thanks

 

[waross]

Yes.
The windings have enough copper to safely carry the heavier current when developing rated power at 380 Volts. There is enough iron to take 415 Volts without saturating. When the windings are connected in star on 693 Volts each winding will still receive 400 Volts.
Connect the motor in delta for 400 Volts.

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

 

[Lc85]

Thanks.
Just to be sure I've got this 100% correct, the clients spec says that their power supply is 400v 50 hz and their motor rated voltage is to be 400v.

So if we connect this weg motor(110kw)in delta it will be fine for the application?

Another concern I have is that what if someone tries to connect it in star?

Thanks again

 

[iceworm]

Another concern I have is that what if someone tries to connect it in star?

Like most anything else: If not connected per the MFG specs - it won't perform per the mfg specs.

Specifically:
Connected Wye, the voltage across each coil is 400/sqrt(3). Motor torque portional to E^2. Speed is portional to frequency. So, the speed-torques curve shape doesn't change, just drops (not exactly true - but should be close enough for this example)

So, motor power drops to ((400/sqrt(3))^2)/(400^2) ----> say to 1/3 of nameplate. You would have a excellent, robust, cool running, 37kW motor, running at the same speed and slip as if it were connected delta across 400V.

ice

Harmless flakes working together can unleash an avalanche of destruction

 

[ScottyUK]

More likely you will have a very unhappy motor running at abnormally high slip and the rotor running far hotter than intended, which will likely fail in short order. If you're lucky it will just stall from lack of torque, but a fan load could find a sweet spot where the motor will run after a fashion.

 

[jraef]

Most likely your motor is designed to be connected in Star for 690V, Delta for 400V (400 is 690 x the sq. rt. of 3). The other voltages mentioned are basically within the tolerance levels of that motor design.

So yes, you will want to connect that motor in Delta if you are going to run it on 400V. DO NOT connect it in Star.

"Will work for (the memory of) salami"

 

[davidbeach]

400 is 690 x the sq. rt. of 3

I sense a slip of the fingers there.

400 is 690 / the sq. rt. of 3

works better, or swap the 400 and the 690 in the original.

 

[jraef]

Multiply, divide, what's a little sign among engineers?...

Actually, I did it extemporaneously then checked it as 690 x .58 because the division key on my ancient desk calculator is stuck! I just screwed up what I called it... because it technically should have said "400 is 690 x the inverse of the sq. rt. of 3", which just sounds stupid. So I fixed it in terms of the verbal description but forgot to swap the places on the values when I changed back from using the inverse... <slaps head>

"Will work for (the memory of) salami"

 

[davidbeach]

;-)