The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 17 replies
  • Subscribers 38 subscribers
  • Views 3030 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Electric Motor Configurations

AdrianWint

So I have a (new) 1.5kW motor.

The motor rating plate declares the machine as being 380V 60Hz 3 phase, 3.96A and then ' WIRED IN STAR'.

The rating plate only gives details about the star configuration - it doesn't mention delta.

Looking inside the terminal box, all 6 wire ends are brought out - three being linked to form the star point.

Removing the star point reveals that all three coils are indeed electrically separate & the opposite ends are all displaced by one position as they would need to be if one was to reconfigure this machine into delta by turning the three links through 90 deg.

My question for the learned forum - why hasn't the manufacturer given any details about the delta configuration on the plate? Indeed he has even specified 'WIRED IN STAR'.

Why would he wish to rule out the use of the delta configuration? What badness might result from me re-configuring into delta & running from 220/3/60? The windings don't care whether they are in star or delta - if I apply 380/3/60 in star or 220/3/60 in delta the winding still has the same voltage across it.

What am I missing?

Parents
  • 0

    My old faithful Brook Motors Pocket Book says that when considering ordering a motor many things need to be considered including:

    a, Frequency of starting,

    b, Reversal requirements,

    c, High Static Friction,

    d, High Inertia Load,

    e, Acceleration.

    f, Limitations on starting current.

    Many Brooks motors could be run on 50 or 60 Hz. supplies. The book mainly covers old traditional methods of starting and control.

    Your new motor should have come with complete technical details either on a printed sheet, or details of online access to such, to allow for correct application for a given job.

    One text book that I have suggests that when using square waves to supply motors an adverse effect can be created. The harmonic energy in a square wave contributes considerably to  Eddy current and hysteresis losses in motors.

    Also, a surprising fact is that the peak value of a first harmonic in a square wave  exceeds that of the square wave.

    Over heating motor link.....

    www.gohz.com/why-vfd-driven-motor-is-hot

    Z.

Reply
  • 0

    My old faithful Brook Motors Pocket Book says that when considering ordering a motor many things need to be considered including:

    a, Frequency of starting,

    b, Reversal requirements,

    c, High Static Friction,

    d, High Inertia Load,

    e, Acceleration.

    f, Limitations on starting current.

    Many Brooks motors could be run on 50 or 60 Hz. supplies. The book mainly covers old traditional methods of starting and control.

    Your new motor should have come with complete technical details either on a printed sheet, or details of online access to such, to allow for correct application for a given job.

    One text book that I have suggests that when using square waves to supply motors an adverse effect can be created. The harmonic energy in a square wave contributes considerably to  Eddy current and hysteresis losses in motors.

    Also, a surprising fact is that the peak value of a first harmonic in a square wave  exceeds that of the square wave.

    Over heating motor link.....

    www.gohz.com/why-vfd-driven-motor-is-hot

    Z.

Children
  • 0 in reply to Zoomup

    "Many Brooks motors could be run on 50 or 60 Hz. supplies".

    All 3 phase electric motors can run on either frequency but with acceptance of the reduced kW rating, speed, efficiency and consequent, increase in running costs, they wouldn't be designed as such however, unless the international market dictates and perhaps with a larger frame size ......... Nought for Nought.

    Jaymack   

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines