Why does an induction machine with a delta connectiom have a smaller pull out torque compared to a star connection

 

I assume you mean an AC Induction motor?
The star delta arrangement allows for two different voltages levels to be applied, either for operation on different level supplies, or to start in a Star-Delta fashion where a high load is present and a 'Soft-Start' is required.
Max.

 

I assume you mean an AC Induction motor?
The star delta arrangement allows for two different voltages levels to be applied, either for operation on different level supplies, or to start in a Star-Delta fashion where a high load is present and a 'Soft-Start' is required.
Max.

Sorry I do not really understand. I might not have made the question clear.

I was playing with a 3 phase induction motor but when I made a delta connection my machine was about to stall above 0.6 Nm torque but this wasn't the case when I used a star connection. I'm not sure why this happened.

 

What is the motor rated at?
It will have a different voltage rating for Delta and Star.
It sounds as though you are using the same supply?
Max.

 

What is the motor rated at?
It will have a different voltage rating for Delta and Star.
It sounds as though you are using the same supply?
Max.

200V for delta

430V for star

 

Hello Hero2222222222. Forgive me if I missed it a 2. Star also known as wye, three phase also known as polyphase. I have attached this link.a very excellent explanation. Please review and I'm sure you will have more questions that we would be more than willing to answer. I did not mean to be so presumptuous I am new here as well.
https://www.allaboutcircuits.com/textbook/alternating-current/chpt-10/three-phase-power-systems/

 

Hello Hero2222222222. Forgive me if I missed it a 2. Star also known as wye, three phase also known as polyphase. I have attached this link.a very excellent explanation. Please review and I'm sure you will have more questions that we would be more than willing to answer. I did not mean to be so presumptuous I am new here as well.
https://www.allaboutcircuits.com/textbook/alternating-current/chpt-10/three-phase-power-systemhi i hs/

I read this and it hasn't really answered my question on why the machine nearly stalled above 0.6Nm with delta connection but not with star connection

 

This gentleman beat me to the punch. If I may be so bold to quote.

Your motor is meant to be connected Δ 230 or Y 380. When you connect Δ, you get full applied voltage across each winding. in Y, you get a voltage divider effect across 2 windings at a time. wye-delta starters are a "soft start" or "reduced voltage start" - they start out in wye, giving less voltage across each winding, and then switch to delta.

torque controllers help reduce mechanical and electrical stress on motor circuits and systems by limiting voltage at start-up. This avoids the over-torque and over-current conditions that happen when across-the-line circuits are completed, like when a basic motor control contactor closes

 

This gentleman beat me to the punch. If I may be so bold to quote.

Yes but there are 3ph motors that are capable of being configured to run in either voltage using star or delta with the same torque.
https://electronics.stackexchange.c...w-do-3-phase-dual-voltage-motor-windings-work
Max.

 

Yes but there are 3ph motors that are capable of being configured to run in either voltage using star or delta with the same torque.
https://electronics.stackexchange.c...w-do-3-phase-dual-voltage-motor-windings-work
Max.

Thank you. Why does the efficiency decrease when torque increases

 

Why does the efficiency decrease when torque increases

Because Torque is directly proportional to the square of the voltage sorry I can't type very fast on this stupid phone I'm using so I'm a bit slow in answering.

 

200V for delta

430V for star

Did you find your answer?
Consider the winding voltage in each case. In delta, it is 200v. In Y it is 430/1.73