Answer / chandrashekar g

I know only abbr. of VFD Variable frequency Drive

Answer / ravi teja

The main purpose of VFD is to control the speed of the motor
in general if u take an induction motor its speed can be
changed either by voltage or by frequency if we made voltage
alone variable also speed will change but only up to certain
point on the other hand if speed control is achieved by
frequency speed control is only possible up to certain
limits beyond that the flux will be saturated

The best method is to control the speed by means both
voltage and frequency but keeping their ratio constant

this can be achieved by means of scr (semi controlled
rectifier) vfd is a closed loop system it takes the feedbsck
of speed from the motor (Tacho genrator or Current Fb)and
adjusts the firing of scr accordingly

Now a days in modern technology Converter or inverter
circuit is 6 pulse or 12 pulse depending on the application

Answer / sankar maiti

VFD Variable Frequency drive. Frequency change also will be
change speed . analog input supply 4- 20 ma through plc to
be change speed and out commend 4-20 ma swing in your scada
on your pc.start stop comment through digital comment.start
to out side the field.

Answer / gulshan

VFD Variable Frequency drive. Frequency change also will be
change speed . analog input supply 4- 20 ma through plc to
be change speed and out commend 4-20 ma swing in your scada
on your pc.start stop comment through digital comment.start
to out side the field.
But we can also control the motor with VFD with a
POtentiometer. We can use the poentiometer instead of PLC.
It also can vary the Frequency

Answer / anup patil

VFD stands for Variable Frequency drive or Variable speed
drive.It is mainly used to change the speed of the motor
from 0Hz to rated Hz of the motor.By doing this you can
operate the motor at variable speed.The advantage of using
vfd in the system to save power by almost 305.It depends on
which type of applications you are using it.

Answer / ashok

VFD stands for Variable Frequency drive we can not incress
the motor rated speed and Frequency IF (1450 RPM & 50HZ)
Any application start from zero RPM to requied as demands.

Answer / nitin pathak

Basically a VFD consists of 3 main components
1)six-pulse rectifier that converts three phase AC voltage
to DC voltage
2)capacitior bank for energy storage which stabilizes the
intermediate circuit DC voltage.
3)six-pulse IGBT inverter that converts the DC voltage to
AC voltage and vice versa.
The motor operation is controlled by changing the firing
angle(switching) of the IGBTs

Nitin Pathak
Lafarge Cement

Answer / baskaran.p

Variable frequency drive:
We can run the Motor and control the speed through plc,
SCADA & Potentiometer.
V
we can run the motor through digital input 24 voltage and
we can run 4-20mA

How to calculate energy stored in an inductance?

0 Answers  

I HAVE BEEN SELECTED FOR APGENCO A.E(ELECTRICAL) 2008.HOW MUCH WEIGHTAGE FOR INTERVIEW AND WRITTEN TEST.HOW I HAVE TO PREPARE. PLEASE GIVE INFORMATION IF U KNOW.WHAT ABT G.D THIS TIME.CALL RATIO 1:2

0 Answers  

what is meant by peak load

2 Answers  

if grounding is notdone at regular intervals for long distance transmission, will the load connected at distribution end receive voltage during negativehalf cycle of the sine wave?

0 Answers   First City,

What is the exact minimum vale of voltage between an earth and netural which can damage or can do malfunction of the electronic equipments ? If this is mentioned in any book, pl.give reference.

0 Answers   Bhushan Power Steel,

how can i get elcctrical supervisor license & Certificate of competancy in gujarat? i have completed my B.E (Electrical) course from gujarat.

2 Answers   NTPC, Welspun,

what is mean by xlpe cables?

3 Answers  

does a DG set has low fault level as compared to that of a transformer.If yes then why.

0 Answers  

why all selected supply voltages are multiple of 11.i.e440,11 kv,33 kv,66 kv,110 kv etc

6 Answers   Suzlon, TCS,

What is C curve and D curve of MCB?

3 Answers   GMR,

How earthing of switchgear system to be done.

0 Answers   KSEB, L&T, Siemens,

in trains i have seen the terminal which is connected at the top of the train is positive .where is negative ? track? i dont think so

9 Answers