Measuring Motor Speed

Hello all
i had a shaft encoder project last year,, in order to measure the speed of a motor
i used opto coupler " photo sensor"
now.. im searching for a new technique to measure motor speed
i mean,, a modified shaft encoder
maybe sensorless
please,, if u have any idea about " new tehniques for measuring motor speed"
or " modified shaft encoder" please tell me
even topics, and a link about that topic
thanx alot & waiting from u
bye

Use the hall effect switch for better operation.
It is really good For speed measurement.

Re:

Hello
thanx for ur reply
but " hall effect switch" it's a sensing method? right??
arent there any sensorless methods?
i found - from my search- sth called "field oriented control" and " vector control",, but really i cdnt understand
would u check this link plz??
**broken link removed**
thanx alot
waiting from u& all
bye

If I could sense something without a sensor, I'd be down the patent office or I'd check the definitions in a dictionary.

Maybe you should describe what you are trying to do a little more.

Mike.

I am agree with the mike but checking the link.

from the link given by haidy
A common approach is to measure the back EMF in the phase windings, which is proportional to shaft speed. Combined with phase drive currents, these back EMF measurements are digitally integrated by the controller to estimate instantaneous rotor position and speed.

This is for stepper motor / biphasic motors
But they also use the second winding for senescing the speed if you note that

Hi,
I am kind of new here...
I need to measure and control speed and also Torque changes of a small 12Volt DCMotor.

Here is the procedure that I am thinking of adopting based on the options that I have.
1) Use a shaft encoder (thickness 2.5mm) and an optical sensor.
2) Read the pulses from the optical sensor using an I/O card installed in a PC
3) Measure the DC motor armature current using a hall sensor.

I am confused in the following aspects.
1) which optical sensor to use [photologic/phototransistor ?] from the following website
**broken link removed**

2) Any I/O card that is being suggested ?

3) Any suggestions as to where to look for to find sensors for finding DC motor armature current ?

Thanks

Haidy said:

Hello all
i had a shaft encoder project last year,, in order to measure the speed of a motor
i used opto coupler " photo sensor"
now.. im searching for a new technique to measure motor speed
i mean,, a modified shaft encoder
maybe sensorless
please,, if u have any idea about " new tehniques for measuring motor speed"
or " modified shaft encoder" please tell me
even topics, and a link about that topic
thanx alot & waiting from u
bye

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