How to estimate the load on a synchronous motor using a magnetometer sensor?

[Hala Helmi]

Looking for any insight on a formula that can be used to calculate the load using a magnetometer sensor for synchronous motor

 

[anorlunda]

Synchronous motor load is proportional to the angle between the rotor poles and the rotating magnetic field in the stator. Angle can also be expressed as phase difference.

If you had a compass needle mounted on the outer perimeter of the rotor by at the pole, out would point in the direction of the rotor angle. So it it's the direction of that magnetic field, not the magnitude.

 

[Hala Helmi]

Many thanks anorlunda,
Is the increase in the load will affect the magnetic field ?
if it is possible can you help me to write the formula

 

[anorlunda]

Where is your magnetometer mounted?
Can it measure direction?

 

[anorlunda]

If you can measure the rotor angle $\theta$, the equation for power will then be $P=P_{max}\sin\theta$.

Where $P_{max}$ is a constant dependent on the details of the grid and the load and the wiring and the voltages.

 

[Hala Helmi]

Where is your magnetometer mounted?
Can it measure direction?

yes, it can measure the direction

 

[Hala Helmi]

Synchronous motor load is proportional to the angle between the rotor poles and the rotating magnetic field in the stator. Angle can also be expressed as phase difference.

If you had a compass needle mounted on the outer perimeter of the rotor by at the pole, out would point in the direction of the rotor angle. So it it's the direction of that magnetic field, not the magnitude.

Hi @anorlunda, I just want to check if I have a synchronous servo motor is this will make any difference

 

[anorlunda]

It applies to all kinds of synchronous motors.

But there is a lot of engineering needed to measure that angle with a magnetometer. But in principle it is possible.

 

[DaveE]

But why not measure voltage and current to estimate load. Those are much easier to deal with IMO.

 

[Hala Helmi]

But why not measure voltage and current to estimate load. Those are much easier to deal with IMO.

Because I want to use a magnetic field sensor to get the load, I'm unable to determine the voltage or current in this case.

 

[Hala Helmi]

I want to ask about If I have accumulator sensor can It be used to detect or determine and calculate the load

 

[nsaspook]

I want to ask about If I have accumulator sensor can It be used to detect or determine and calculate the load

https://forum.allaboutcircuits.com/...sor-for-synchronous-servo.191479/post-1793148