i have a project..and i have to ask something about how to stop the motor
let consider we have a motor (dc) .producing temperature..and a thermistor (ntc) is there...if the temperature is increased another motor(fan) is running to cool the system...
my aim is how to stop the running(dc motor ..first one..that produces temperature)
automatically means that fan is in working conditon and the same time the first motor stops..
please help me to complete this project
What is the load of your main motor m1? Depending on the load features, you will decide the proper means to stop the motor, there is not universal way for all cases.
well the simplest ways is that get a zener diode of the voltage which would be equivalent to the output of the thermistor at temperature at which you want to stop that motor then connect the cathode of the zener to the output of thermistor and the anode to a base of NPN the collector has to be connected to the vcc of the dc and the emitter have to be at ground...
now what happends is that when the specified temperature is approached then the zener will start opearting and switch the NPN on and the entire vcc will go towards the ground and will make the dc motor off...
Do you know some small fan like the one we use for cooling the cpu in computer graphics card? it has 3 cable instead of two. the fan has a temperature sensor in it, once it gets hot it will turn on the fan. to turn off the first motor you just have to sense if the fan is on, then turn off the motor. i hope this will help, i do not know the size of cooling you need.