Showing posts with label speed. Show all posts
Showing posts with label speed. Show all posts
Tuesday, May 14, 2013
PWM Motor Speed Control Circuit
Here is a simple PWM motor speed controller circuit that can be used for varying the speed of low power DC motors .The variation in speed is achieved by varying the duty cycle of the pulse supplied to drive the motor.Of the two gates of IC CD40106B ,N1 is wired as an inverting Schmitt Trigger astable multi vibrator for producing pulses and N2 as an inverting buffer to drive the transistor during positive cycles at base.The duty cycle is set from resistor R2. R1 limits the base current of transistor SL 100.The circuit is ideal for controlling toy motors,hand held mini fans , small blowers etc.
Wednesday, April 3, 2013
DC Motor Speed Controller
This circuit takes advantage of the voltage drop across bridge rectifier diodes to produce a 5-position variable voltage supply to a DC fan or other small DC motor. It is not as efficient as a switch-mode circuit but it has the virtues of simplicity and no switching hash. The four full-wave bridges are connected so that each has two pairs of series diodes in parallel, giving a voltage drop of about 1.4V, depending on the load current.
Circuit diagram:
DC Motor Speed Controller Circuit Diagram
The rotary switch should have "make before break" contacts which should be rated to take currents up to about an amp or so. For higher currents, higher rated bridge rectifiers and a suitably rugged rotary switch (or solenoids) will be required. If you want smaller voltage steps, you could use the commoned AC inputs on the bridge rectifiers to give intermediate steps on the speed switch.
Source by : Streampowers
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