Multispeed motor issue.

[Fernando79]

Hello Guys ,

I have very strange case happen with me today . I hope someone can explain that to me cause I went to look for it and I didn’t find explanation.

I have multi speed AC motor 1800/900 rpm 25/15 HP. this is from the drawing , I ran this motor at high speed 1800 and the current was 11.6 A , I ran the motor at 900 rpm and the current was 23.8 A ?!!! does that make sense ???
anyone knows what exactly should happen for the current ?? do you guys think I have problem in the poles connection and I don’t have these right speed . one thing I am sure that when the motor was fast visually was less current and as what I mentioned before.

Thanks Folks.

Fernando

 

[Fernando79]

Sorry I forget to tell that this motor 480 V, 60 HZ and the application for Blade motor to cut pipes (Steel plant) !!

Thanks again .

 

[itsmoked]

What voltages??????????????????????????????????????

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Hey Keith, the dreaded one second double post got you.
Fernando79, Were the currents read with the motor loaded or unloaded?
respectfully

 

[Fernando79]

When the motor not loaded !!

Thanks

 

[eemotor]

Fernando,
The motor may be just fine. Multispeed motors may exhibit higher no load current in low speed than high speed due to high magnetizing current required by the low speed connection.

 

[edison123]

eemotor

23.8 amps at no-load ? That is more than the load current.

Fernando

Did you check the speed at lower speed ?

*Even inside a hard-boiled egg, there is a golden heart!!!*