Panel switch wiring

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

             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.

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.

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

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.

How to Check if a Remote Control is Transmitting an Infrared Signal. Many households have 5 or 6 remote controls laying around the house. This is the simple Remote control tester schema diagram. When the remote control is not working, first check the battery before, It may be loss.If it is good,so detect transmit infrared light device.However, because the human eye can not see infrared light,so can not know how good or bad.But the photo transistor can use to detect infrared light. 

This schema so use this photo transistor is the light receiver from the remote control.If it is nice to have the bias current of the transistor BC558.It runs a current flows through the LED,so the LED bright.The remote control that works correctly. The variable resistor VR1 is used to adjust the sensitivity of the schema.

 

This circuit exploits the high slew rate, high input impedance, and high output-voltage capability of CA3140 BiMOS op amp. It also provides mid-band unity gain with standard linear potentiometers.

This schema will allow you to connect any tape recorder that has a mic and remote input to a phone line and automatically record both sides of a conversation when ever the phone is in use. You will need to take a couple of voltage readings before connecting the schema. First determine the polarity of your phone line and connect it to the schema as shown and then determine the polarity of the remote input and connect it to the schema. Circuit operation is as follows. When the phone is on hook the voltage across the phone line is about 48volts dc. When the phone is off hook the voltage will drop to below 10volts dc. When the line voltage is at 48volts the FET is off which causes Q2 and Q3 to be off. When the phone is picked up the FET turns on along with Q2 and Q3 which turns your recorder on. The tape recorder must be in the record mode at all times. As you can see the power source for the schema is the phone line.