Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Supply 460v single phase instead of 230v to induction machin

  1. Dec 11, 2015 #1
    I am planning to run 230V single phase machine with 460V single phase supply. what will be the effects in RPM and torque??? (( this is how i thought: as we increase voltage , current will decrease since power is same...decrease in current decreases the torque.....to maintain same power, decrease in torque is counteracted by increase in speed....SO MY CONCLUSION IS THAT IF I INCREASE VOLTAGE MY SPEED WILL INCREASE AND TORQUE WILL DECREASE....IS THAT RIGHT???? WHAT PERCENTAGE THE SPEED WILL INCREASE AND TORQUE WILL DECREASE????))
    AND MY CONSTRAINT IS THAT I HAVE TO MAINTAIN SAME RPM!! WHAT CHANGES SHOULD I NEED SO THAT 460V AND 230V PRODUCES SAME PERFORMANCE!!!

    I will be very thankful for your help.
     
  2. jcsd
  3. Dec 11, 2015 #2
    If you increase the voltage input to your machine (is it some kind of electric motor?), above what it rated for, that will result in it drawing more current.
    More current means that it will try to spin faster = more torque.
    However there is a good chance that some coil will just burn up because it's not designed for that.
    Why the caps?, it won't make any difference to the result.
     
  4. Dec 11, 2015 #3

    correct me if i am wrong.. assume that motor is under no load, motor will draw current only when we apply load (though it consume some current as it is required to produce magnetic filed)..now my aim is to achieve same performance with 460v as that of 230v supply (both single phase)....what will there effects on torque and speed?? (according to me torque will decrease and speed will increase)....and what are the changes should i need to make in 230v supply motor so that same torque and speed is achieved?
     
  5. Dec 11, 2015 #4

    anorlunda

    User Avatar
    Science Advisor
    Gold Member

    No. Your reasoning about what increases and decreases is not even close to correct. Read the Wikipedia article about induction motors to learn about RPM versus torque.

    Srinagar is right, something will burn up and the motor may start a fire,
     
  6. Dec 11, 2015 #5

    Daz

    User Avatar
    Gold Member

    Connecting a machine rated for 230V operation to a 460V supply is reckless and dangerous. It could start a fire or lead to death or injury by a variety other means.

    Where I live you could be sent to prison for doing that, if it hurt or killed someone.

    Also, induction motors run at (or below) a fixed speed determined by the frequency of the supply, called the synchronous speed. Increasing the supply voltage won’t increase the speed but will hugely increase power dissipation.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Supply 460v single phase instead of 230v to induction machin
Loading...