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

Click For Summary

Discussion Overview

The discussion revolves around the implications of supplying a 230V single-phase induction machine with a 460V single-phase supply. Participants explore the effects on RPM and torque, as well as the necessary adjustments to maintain performance. The conversation includes technical reasoning, safety concerns, and the operational characteristics of induction motors.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that increasing the voltage will decrease current, which would reduce torque but increase speed, leading to a conclusion that speed will increase and torque will decrease.
  • Another participant argues that increasing the voltage will result in the machine drawing more current, potentially leading to increased torque and a risk of burning out coils.
  • A later reply emphasizes that the reasoning about torque and speed is incorrect and warns of the dangers of connecting a 230V machine to a 460V supply, citing risks of fire and injury.
  • Concerns are raised about the fixed speed of induction motors being determined by supply frequency, indicating that increasing voltage does not affect speed but may increase power dissipation.

Areas of Agreement / Disagreement

Participants express conflicting views on the effects of increasing voltage on torque and speed, with no consensus reached on the correct implications or necessary adjustments for maintaining performance.

Contextual Notes

Participants note the potential for dangerous outcomes when operating equipment outside of its rated voltage, highlighting the importance of safety and proper electrical practices.

srinaath
Messages
51
Reaction score
2
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.
 
Engineering news on Phys.org
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.
 
rootone said:
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.
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?
 
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,
 
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.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
Replies
9
Views
2K
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
13
Views
4K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 31 ·
2
Replies
31
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
Replies
4
Views
3K
  • · Replies 37 ·
2
Replies
37
Views
8K