Motor Controlling Circuit Required

[Nab AC Analysis]

Hello
I need a Circuit of Motor COntrolling System (Stepper or DC )by using Difference Amplifier I want to rotate the Motor .
Plzz Help mee

 

[Styx]

motor canotrl is not easy, some more info is required thanks

 

[Nab AC Analysis]

I don't have much information about it have a rough idea regarding controlling the mottor It's like need to use NPN and PNP Transistors and Potentiometer to rotate the mottor ... nothing else more than that have search alot and read some books but did;nt find the exact circuit to work cuz i have to submitt the project at 15th of October .....
Do you guys have any idea of writting a Publishing Paper on your Project (Not a Project Report) Publishing Papers which consist of just 3 written material.
Hope i will get something from you guys now.

 

[bmcculla]

You can build a simple proportional controller with a difference amplifier. A porportional controller will work for a DC motor not a stepper motor.

For a proportional controller you need a feedback signal. Current would be the easiest thing to sence and because current is proportional to motor velocity it would be easy to do speed control. So you need a current sensing resistor (somthing around 1 ohm depending on how much cuurent). Then you need a Power transistor NPN is probably the easiest. So the cruuent sensing resistor connects to ground on one end and the NPN emiter on the other end. This node gives you your feedback signal. The NPN collector connects to the motor. Your difference amp (just an op amp set up as a difference amp) amplifies the difference between the voltage from the pot (+ input) and the feedback voltage(- input). the output is connected to the base of the NPN transistor.

The easiest way to think about this circuit is to imagine the motor is spinning to slowly. The feedback voltage will be small compared to the pot voltage so the NPN transistor gets turned on more which increases current to the motor causing it to spin faster. The same sort of thing happens but in reverse when the motor is spinning too fast.

You will need to be able to change the gain of your difference amp. The higher the gain the better the speed control but at a certain gain the motor will start to spin unpredicatably. This happens because there is a delay between the current in the motor and the output of the difference amp. At high gains the delay is long enough that the output of the difference amp is backwards of what is should be which makes the motor spin crazily.

Hope this helps.
Brent

 

[Nab AC Analysis]

THanks for this it clears my concept alot i think Potentiometer is required in roatating the motor but someone told me that i need to open the potentiometer and to use the one pin of it directly attached to motor .Can i get the Perfect Schematic Diagram?

 

[Nab AC Analysis]

THanks for this it clears my concept alot i think Potentiometer is required in roatating the motor but someone told me that i need to open the potentiometer and to use the one pin of it directly attached to motor .Can i get the Perfect Schematic Diagram?