Panel switch wiring

Sunday, September 7, 2014

Methods of Speed Control of Induction Motor

There are the following two methods for the Speed control of the Induction motors.

Speed control by Voltage Variation or Stator voltage Control Method.

The Induction motor speed can be controlled by changing the applied voltages the stator , Because in induction motor the out put torque is Directly Proportional to the Squire of the voltage and inversely proportional to the resistance of the rotor, while S= Slip.

T∞ V²/Rr S

Thus the motor speed controlled with out changing the supply frequency, for example, if the supply voltage value is decreases to its half, the motor torque is decreases ¼ times; the torque is directly proportional to the speed of the motor.

In stator voltage control method, the stator voltage is controlled by a SCRs, these SCRs are connected with three phase supply (With each Phase) in anti parallel conduction, the out put voltage of the SCR is controlled by the firing angle of the SCR, Increasing the firing angle, decreases the out put voltage and this way the speed of the induction motor is decreases. By decreases the firing angle, increasing the out put voltages and the speed of the motor is increases.

In the give ckt an induction motor is shown, with each phase of the motor the SCRs are connected in anti parallel conduction.

In this ckt two SCR are conduct at the same time, this way a very large current flow through the Stator, therefore this method is used for small or medium size motors.

Speed control by Frequency Changing or Variable Frequency control method.

The frequency method is very important through which the speed of the induction motor is controlled.

Ns = 120f/P

Form the above formula, it is clear that the speed of the induction motor directional proportional to the frequency. It means that the frequency of the supply voltage changes , the speed of the indication motor also changes , increases the in put frequency of the supply increases the speed of the induction motor also increase and vice versa.

In the frequency controlled method, the three phase supply is controlled through a controlled rectifier. The voltage is applied on the forced Commutated Bridge rectifier, which produce a variable frequency for control of the induction motor.

PWM Speed Motor Controller

This is very useful schema.When we use high speed moters(Pwm)We need a schema to boost the speed so this is the schema for it.This schema can generate 170-200Hz frequency.This schema operates with 4.5V to 6V.

Note

# Use IN4148 diodes for this

Friday, August 29, 2014

DC Motor Speed Controller

DC Motor Speed Controller Circuit Diagram. This schema 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 schema 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.

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.

Author: Stephen Butcher,

Wednesday, August 27, 2014

Speed Control of DC Motor PWM Wiring diagram Schematic

Speed Control of DC Motor PWM Circuit Diagram. Often, people try to control small DC motors with a variable resistor type potentiometer connected to a transistor. This system until works well but it generates heat and thus loses power. This schema is a simple schema for modulating the pulse width for controlling the DC motor, it eliminates this problem.

Speed Control of DC Motor PWM Circuit Diagram

The schema is capable of controlling the engine speed pulses (PWM), these pulses have a duration variable to change the speed of the motor. The longer the pulses lead, the faster the motor will rotate, and vice versa.

R1 1 Meg 1/4W Resistor
R2 Potentiometer 100K
C1 0.1uF 25V Capacitor Ceramic Disc
C2 0.01uF 25V Capacitor Ceramic Disc
Q1 MOSFET IRF511 or IRF620
U1 4011 CMOS NAND
S1 KEY
M1 Motor

The resistor R2 adjusts the speed of the oscillator and thus the speed of the motor, the motor can be any DC motor that operates from 6V and having no more power than the maximum current of Q1. The voltage can be increased by connection to a higher voltage to switch instead of 6V which feeds the oscillator.The Q1 will need a heat-sink. If you need to use the IRF620 that supports up to 6A.

Monday, August 11, 2014

Build a 1000W AC Motor Speed Controller Wiring diagram Schematic

Build a 1000W AC Motor Speed Controller Circuit Diagram, this is a simple1000W AC Motor Speed Controller Circuit Diagram. This triac based AC motor speed controller schema is designed for controlling the speed of AC motors like drill machines, fans, vacuums, etc. The speed of the motor can be controlled by changing the setting of P1 potentiometer. The setting of P1 determines the phase of the trigger pulse that fires the triac. The schema incorporates a self-stabilizing technique that maintains the speed of the motor even when it is loaded.

1000W AC Motor Speed Controller Circuit Diagram

Sunday, September 7, 2014

Methods of Speed Control of Induction Motor

PWM Speed Motor Controller

Friday, August 29, 2014

DC Motor Speed Controller

Wednesday, August 27, 2014

Speed ​​Control of DC Motor PWM Wiring diagram Schematic

Monday, August 11, 2014

Build a 1000W AC Motor Speed Controller Wiring diagram Schematic

Speed Control of DC Motor PWM Wiring diagram Schematic