What is LCI in electrical?

Load Commutated Inverter (LCI) is a system with an input thyristor bridge and an output thyristor bridge. The input bridge is naturally commutated by the AC supply and supplies DC current with harmonics into a large inductor.

How does a VVVF drive work?

Variable Voltage Variable Frequency (VVVF) Lift Drive employs frequency inverter technology which regulates input voltage and frequency throughout the journey, drawing much less current during acceleration and deceleration.

What is VSI drive?

Definition: The voltage source inverter is defined as the inverter which takes a variable frequency from a DC supply. The voltage source inverter use self-commutated device like MOSFET, IGBT, GTO, etc. It is operated as a stepped-wave inverter or a pulse width modulation.

When can a synchronous motor be load commutated?

When can the synchronous motor be load commutated? When the synchronous motor operates at a leading power factor thyristors of load side converter can be commutated by the motor induced voltages same way as the thyristors of a line commutated converter are commutated by line voltages. 25.

What is meant by load commutation?

Load commutation of SCR is a forced commutation technique in which SCR is forced to turn off. Turning off an SCR essentially requires its anode current to fall below holding current and a reversed biased voltage must be present across SCR for sufficient time so that SCR may regain its blocking state.

What is the difference between VFD and Vvvf?

Most commonly, the terms VFD and VSD are interchangeable. The term VVVF is often used in the mining industry – it refers to a variable voltage variable frequency drive. It describes exactly the same AC drive as the term VFD – any AC drive will automatically control voltage to suit the frequency it is running at.

What are the advantages of VSI drive?

Voltage source inverter is more suitable for multi-motor drives. Low weight, volume and cost. Simpler control and efficient operation. Regenerative braking capability.

What is the main disadvantage of synchronous motors?

Disadvantages of Synchronous Motor Synchronous motors require dc excitation which is supplied from external sources. These motors are not self-starting motors and need some external arrangement for its starting and synchronizing. The cost per kW output is commonly higher than that of induction motors.

At what speed do synchronous motors run?

1,800
Thus, the power rating for the frame, being the product of torque and speed, will be roughly inversely proportional to the number of pole pairs. The most common synchronous speeds for 60-hertz motors are 1,800 and 1,200 revolutions per minute.