Crawling and Cogging

Crawling

• Sometimes the induction motor starts to run at one seventh speed of synchronous speed, it is called as crawling in the induction motor.

Mutual Coupling

Coupling

• When two coils ( or more than two coils ) are connected by common magnetic flux, they are called as coupled with each other.

Energy Stored in the Capacitor

• When DC supply is given to capacitor, some energy is stored in the dielectric medium of capacitor. 
• When capacitor is discharged, this electrostatic energy released.

ELCB ( Residual Circuit Breaker-RCB )

Principle of ELCB

• The working principle of ELCB is based on core balance or differential current protection. When there is no leakage or fault in the system, the current passes through phase and neutral is same.

Starting Torque in the Three Phase Induction Motor

Starting torque

• The torque in the DC Motor is related by the product of field flux and armature current whereas the torque in the induction motor is product of rotor flux, rotor current and rotor power factor.

Full load or Running Torque in the Three Phase Induction Motor

Full load torque

• The torque in the DC Motor is related by the product of field flux and armature current whereas the torque in the induction motor is product of rotor flux, rotor current and rotor power factor.

Charge, Current , Power , Potential and Potential Difference

Charge and Current

• The law of conservation of energy states that the charge can neither created nor destroyed, it can only transferable from one place to another place. 

Synchronous speed, Slip speed, Slip, Rotor speed

Synchronous speed

• The speed of the stator magnetic field in the three phase induction motor is known as synchronous speed.