Autotransformer starting

 Autotransformer starting

This method also aims at connecting the induction motor to a reduced supply at starting and then connecting it to the full voltage us the motor picks up sufficient speed. 

Figure shows the circuit arrangement for autotransformer starting. 

The tapping on the autotransformer is so set that when it is in the circuit, 65% to 80% of line voltage is applied to the motor

At the instant of starting, the change-over switch is thrown to "start" position. 

This puts the autotransformer in the circuit and thus reduced voltage is applied to the circuit.

Consequently, starting current is limited to safe value. 

When the motor attains about 80% of normal speed. the changeover switch is thrown to "run" position. 

This takes out the autotransformer from the circuit and puts the motor to full line voltage. 

Autotransformer starting has several advantages viz low power loss, low starting current and less radiated heat. 

For large machines (over 25 H.P.), this method of starting is often used. 

This method can be used for both star and delta connected motors.




Comments

Post a Comment

Popular posts from this blog

Electrical Electronics Communication Telecom Engineering Topics Explanation

Introduction to DC-TO-DC Converter  ||| Power Switching Devices Zones of Protection System And His Type  |||  There are six main causes of electric   |||   motor failures  |||  Top Electrical Engineering Interview Questions And Answers  |||  What Is Solar Panel  |||   How Does Solar Panel Work?  |||    What is Logical Circuit?  |||   What is Batter and Types of Battery?  |||   What is Current?   |||  What is Voltage?   |||  What Is Diode?     ||| Circuit Breakers and Rating Of CB  ||| Dry Type Transformers are Self-Extinguishing And Fire Resistant  |||  Kirchhoff's Laws  ||| Difference between AC and DC  ||| Define Amplitude, instantaneous value cycle, Time period, frequenc  ||| Common Causes of Electric Motor Failures   |||   All About Electric Motor  ||| Basic Concept Of Electrical Earthing and Groundin...
Read more

Electrical Transformers

 Electrical Transformers Principle of Electrical Transformers   Click To Read   Transformers Action       Transformers V.I Click To Read                         Click To Read   Transformers Magnetic Circuit                   Click To Read   Auto Transformer       Click To Read   Instrumental Transformer           Click To Read   Potential Transformers           Click To Read   Transformers Bush  Current Transformer       Click To Read                 Click To Read   Tap Transformers    Transformers Polarity       Click To Read                Click To Read   Single Phase Transformers Connections        ...
Read more

Electrical Engineering Top Interview Questions And Answers 50 t0 100

51: Explain the working principal of the circuit breaker? 52: In the motors starting purpose why the armature rheostats at maximum position while the field rheostat is kept in minimum position? 53: What is the significance of vector grouping in Power Transformers?   54: Advantages of vvvf drives over non vvvf drives for EOT cranes?   55: How can you start-up the 40w tube lite with 230v AC/DC without using any choke/Coil?   56: What is electric traction?   57: Why computer humming sound occurred in HT transmission line?   58: What's the one main difference between UPS & inverter ? And electrical engineering & electronics engineering?   59: What is meant by armature reaction?   60: What is Potential Transformer (PT)? 51: Explain the working principal of the circuit breaker?   52: In the motors starting purpose why the armature rheostats at maximum position while the field rheostat is kept in minimum position? 53: What is the significance o...
Read more