×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

European motor tricks?

European motor tricks?

European motor tricks?

(OP)
We have a couple of examples at our company of European OEMs who purposely wire motors for the lower voltage (277) and yet run them at the higher voltage (480). I have talked with a European tech who once told me that there was some trick like this that they did to get more power out of a motor. Does anyone here know the logic behind this?

Thanks

RE: European motor tricks?

He told you half the truth.

This is sometimes being used when you have a VFD. By connecting for the lower nominal voltage and running them at a frequency that is 480/277 times nominal frequency and at 480 V, you get same torque at higher speed. And, presto! More power out of that motor.

Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: European motor tricks?

The function is used typically on motorised gearboxes that have a VFD. The output frequency would typically be set to 87Hz (where the supply frequency is 50Hz) and will allow you to use a smaller (cheaper) gearbox that has a higher ratio gear-train but resulting in the same output torque. It is a cost saving function that many OEM's have introduced (I know Bonfiglioli/Flender/SEW do this).

RE: European motor tricks?

Running a motor on higher frequency and proportional increased voltage, constant torque (approx. constant air-gap flux density) increases the core laminations magnetic losses and the friction and windage. The result is a reduced motor life expectancy due to increased stress, thermal on the insulation and mechanical on the bearings and rotor. But certainly the power output is increased due to the speed increase; HP= rpm*Torque/5252, (Torque in Ft-Lb)

RE: European motor tricks?

(OP)
Cool deal, thanks - this sounds familiar and makes sense. I went out and looked at the latest example of a motor that we have here that is wired like this - it's only running at around 48 Hz - so this may be an actual case of accidental miswiring or maybe just a bad calculation on how fast the machine would run in production.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources