- #1
meitl
- 3
- 0
I found an old circuit diagram online but have never been able to find it again.
Here is what I am trying to do:
The three-phase DC motor I am working with is a 4-pole motor. Therefore there is a direct relationship between the frequency between the motors phase-leads, and the current RPM of the motor. IE - 2 magnetic cycles per revolution
What I need to do is take frequency measurements between the leads and convert that to a voltage that is representative of the motors RPM, which i can then display on a LCD voltage meter. I believe this to be a much cheaper method of obtaining a tachometer (plus it is an interesting project).
Interesting side-note: Using wheel radius and gear ratio I could easily output MPH using op-amps, although it would be inaccurate while the car is gliding in neutral.
If anyone has any ideas or links to a good circuit diagram it would be greatly appreciated. My background is in Physics, so my ability to design complex circuits like this is very limited without extensive research.
Here is what I am trying to do:
The three-phase DC motor I am working with is a 4-pole motor. Therefore there is a direct relationship between the frequency between the motors phase-leads, and the current RPM of the motor. IE - 2 magnetic cycles per revolution
What I need to do is take frequency measurements between the leads and convert that to a voltage that is representative of the motors RPM, which i can then display on a LCD voltage meter. I believe this to be a much cheaper method of obtaining a tachometer (plus it is an interesting project).
Interesting side-note: Using wheel radius and gear ratio I could easily output MPH using op-amps, although it would be inaccurate while the car is gliding in neutral.
If anyone has any ideas or links to a good circuit diagram it would be greatly appreciated. My background is in Physics, so my ability to design complex circuits like this is very limited without extensive research.