Engineering Q&A
what is variable frequency drive ?
in Electrical Engineering by

Your answer

Thanks for your contribution. Feel free to answer this question. Please avoid short answer. Your answer is most welcome. Be genuine.

Upload image or document:

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.

2 Answers

0 votes

Variable Frequency Drive (VFD)

image

image

image


 

•The VFD control the speed of three phase induction motor by varying the frequency and voltage.

•The difference between synchronous speed and rotor speed is called slip.

•By varying the synchronous speed the rotor speed can be varied.

•Synchronous speed is directly proportional to frequency and inversely proportional to number of poles.

•VFD consist of rectifier stage, inverter stage and control.

•Rectifier is a six set of diode bridge which converts AC to DC.

•Between rectifier and inverter there is a filter which smoothen the DC.

•Inverter is six set of IGBT or GTO or SCR which converts the DC to variable AC with control system.

•Control system maintain the constant ratio of voltage to frequency.

•VFDs are of three types one is Current source inverter (CSI) second is voltage source inverter (VSI) and third is pulse width modulation (PWM) VFD.

•The CSI consists of large and expensive inductors so it gives smooth current.

•VSI VFD have poor power factor.

•So the third one means Pulse Width Modulation (PWM) VFDs are most commonly use because of good power factor and low cost.

•In the control of VFD the PWM method is used.

by
0 votes
by

Related questions

1 answer
asked Sep 13, 2017 in Power Electronics by Quiz | 25 views
2 answers
1 answer
asked Aug 15, 2017 in Electrical Engineering by Zeeshan | 63 views
0 answers
0 answers
1 answer
asked Apr 12, 2018 in Electrical Engineering by Shimroz123 | 17 views
1 answer
asked Mar 31, 2018 in Electrical Engineering by Shimroz123 | 12 views
1 answer
0 answers
asked May 25, 2018 in Resonance by Shimroz123 | 29 views
0 answers
0 answers

Welcome to electronics2electrical.com here you can ask questions related to electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc.
Be respectful to all the members. Do not copy and paste the answers from other websites which have copyright content. While asking question give full details about it.

Most popular tags

power motor dc circuit transformer voltage current used system phase resistance factor synchronous load ac energy induction electric generator series frequency between speed capacitor use electrical meter line difference control type mosfet transmission magnetic plant high single instrument bjt unit source advantages function diode and machine winding field define torque parallel amplifier supply shunt thyristor motors electricity arduino maximum time relay armature problem value on transformers types coil diagram state flow ratio material three formula starting direction theorem method emf operating efficiency digital wave microprocessor test instruments inductance loss measure operation connected signal low applications effect single-phase network temperature working constant losses different law wattmeter measuring compare controlled breaker drive device logic rc full switch flux wire resistivity disadvantages free of materials machines angle force converter conductor transistor gain open protection scr core measurement number bridge principle generators reactance circuits negative the friction iron loop short pole battery conservation steam resistors hysteresis computer using analog lines secondary station gate a rectifier inverter linear induced relays nuclear capacitance basic characteristics design direct work rotor electronics ammeter forces diesel damping rlc connection factors capacitors minimum insulation moving regulation running self systems air fault range main stability quality starter igbt eddy alternator ideal rl average 3-phase plants arc thermal error fuzzy biasing dielectric pressure balanced superposition errors copper rotation feedback impedance measured electronic electrons charge inductive transfer explain start off back curve over solar is three-phase tariff locomotive peak bias zener engineering commutator surge conductors rating universal potentiometer density permanent mechanical transducer capacity memory adc excitation two fuse pure harmonics application semiconductor inductor internal pmmc reaction welding resonance traction permeability breakers rms designed electromagnetic si generation brushes switching capacitive shaded rate 1 distribution resistor methods delta star oscillator reluctance simplification algebra 8085 boolean weston dynamometer insulating strength installation definition fuel heating earth units
8,574 questions
7,174 answers
135 comments
3,091 users