Electrical World

Introduction                 Variable frequency drive (VFD) or adjustable frequency drive(AFD),Variable -voltage/Variable frequency(VVF) drive,Variable speed drive(VSD),AC drive,Micro drive or inverter derive is a type of adjustable speed drive used in electro-mechanical drive system to control AC motor speed and torque by varying motor input frequency and voltage. Working Of VFD                  The first stage of a variable frequency AC drive or VFD is the converter.The converter is comprised of six diodes used in plumbing system.They allow current to flow in only one direction the direction shown by the arrow in the diode symbol..For example whenever A Phase voltage (voltage is similar to pressure in plumbing system) is more positive than B or C phase voltages,  then the B-phase diode will open and allow current to flow .When B -phase become more positive than A -phase then the B-...

History Of Circuit Breaker                  An early form of circuit breaker was described by Thomas Edison in an 1879 patent application , although his commercial power distribution system used fuses.Its purpose was to protect lighting circuit wiring from accidental short circuits and overloads. Installation Of First Circuit Breaker                The BOSTON Electric light company in 1898 used the first installed breaker at the local     L Train Station. Working Principle Of Circuit Breaker                Circuit Breaker essentially consists of fixed and moving contacts .Whenever a fault occurs on any part of the system,the trip coil of the breaker gets energized and the moving contacts are getting apart from each other by some mechanism , thus opening the circuit. Design Of Circuit Breaker For Given Load   ...