capacitor start capacitor run motor is the type of single phase induction motor that is also known as double value capacitor motor . It is used to convert electrical energy into mechanical energy, just like another induction motors. There are two types of winding are used secondary winding and main winding with phase displacement of 90° in a space.
In capacitor start capacitor run motor two capacitor are used. One for starting purpose and another one capacitor is used for maintaining continuous speed.
connection diagram of capacitor start capacitor run motor
two capacitors are used in capacitor start capacitor run motor , starting capacitor (Cs) and run capacitor (Cr) . Two types of windings are used. main winding and starting winding . Main winding is also known as running winding and starting winding is also known as auxiliary winding. Main winding and starting winding, both are displaced by 90° in a space.
To achieve high starting torque, we have requirement of large starting current. so capacitive reactance of starting winding is low .
reactance of a starting capacitor is given by ( Xs = 1/Wcs ) , as starting capacitor short time rated electrolytic capacitor is used .
during normal operation rated line, current should be smaller then the starting current, that’s why capacitive reactance of running capacitor remain high .
reactance of run capacitor is given by ( Xr = 1/Wcr ) ,
In capacitor start capacitor run motor a squirrel cage rotor is used or cage type rotor is used and a centrifugal switch connected with a starting capacitor that is used to disconnect a starting capacitor from the circuit .
working of capacitor start capacitor run motor
since a starting capacitor connected in series with auxiliary winding and high torque is required in the starting , so capacitive reactance of starting capacitor remains low . so that maximum current can flow through starting capacitor.
when high current flow through starting capacitor then starting torque is also high because torque is directly proportional to current . Torque of motor increases with increasing in current.
and at normal speed running capacitor, play important role. Since running capacitor have high capacitive reactance , so low current flow through running capacitor. And due to low current torque also get reduced at normal speed.
during operation of machine high torque is required at starting and low torque is required during normal speed that achieved by starting and running capacitor. When motor achieve the speed about. 70 to 80% of their full speed then starting capacitor get disconnected by the help of centrifugal switch , and motor runs continuously with the help of run capacitor. Thus capacitor start capacitor run motor operates.
Phasor diagram of capacitor start capacitor run motor
At a starting Both capacitor, maintain the angle greater than 90° that’s why in a starting, we get higher torque . And at normal speed phase angle remain 90° so torque get reduced at normal speed and at normal speed starting capacitor, get removed by the help of centrifugal switch. so the Phasor diagram shows that during a starting of motor phase angle remain greater than 90° and at normal speed of the motor, starting capacitor get disconnected and running capacitor has phase angle about 90° so torque get also reduced compare to starting torque.
Characteristics
according to characteristics of capacitor start capacitor run motor when both capacitor are connected in circuit, then we get higher torque because we require higher torque in starting. And when starting capacitor get removed after achieving the speed, 70 to 80% of their full speed, then torque get also reduced at normal speed.
- this type of motor provides quite and a smooth operation
- capacitor start capacitor, run motor have higher efficiency
- this type of motor commonly used in different application due to their constant torque.
- there are no any vibration in this type of single phase induction motor because it have constant speed.
Advantages
- running capacitor that we use in the capacitor start capacitor run motor enhance its performance
- this type of motor provides higher efficiency
- these type of motor have high power factor due to permanent capacitor is used
- it provide high, pull out torque
- we use capacitor in the capacitor Start capacitor run motor , have no maintenance requirement till 10 years.
- this type of single phase induction motor provides constant torque characteristics
- it has compact and lightweight design
- this type of motor is self starting so external starting device is not required to operate the motor.
- it provide higher durability and reliability
Applications
- in different machine tools, dual capacitor motor is used
- it is used in compressors
- dual capacitor motor is used in conveyors
- capacitor start capacitor run motor is used in pumps
- these type of motors are used in AC compressor
- it is used where silence is important like hospitals, Studios, and other places
conclusion
This is all about capacitor start capacitor run motor where two types of capacitor are used to create the phase difference that is starting capacitor and running capacitor. Initially both capacitor are operates and after achieving the rotor speed about 70 to 80% starting capacitor get disconnected by the help of Centrifugal switch.
In previous article, we have learnt about capacitor start induction run motor that is type of single phase induction motor just like capacitor start capacitor run motor main difference between both motor capacitor start induction run motor have only one capacitor that is used to create the phase difference between the current and in capacitor and capacitor run motor two capacitor are used to maintain the constant speed and create greater torque in a starting . So keep supporting and read all articles that I linked below, and I have provided other article link below this article . On this website, you will get all subject theory related to your academic exams, particularly diploma, and B.Tech in electrical engineering . Also, I have any YouTube channel (mind of engineer) you can visit there to get related topics videos where I have explained in easy way so that students can easily understand all the topics related to academic exams of diploma and BTech in electrical engineering.
- capacitor start capacitor run motor – video