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

what is the difference between earth and neutral.

9 Answers   DLF,

cause of failure of transformer bushes

3 Answers  

Different STANDARDS (BS, IS, IEC etc) gives different informations on CT specification. How they correspons w r t each other (i.e I mean to say BS provides "knee point voltage" but IS does not, then how can i select CT)

0 Answers  

Why in India only 50hz frequency not 60hz

2 Answers   Prism Cement,

what is skin effect?

4 Answers  

What is the Procedure for selecting a Cable, Breaker and Transformer for particular load.

3 Answers  

In three pin plug 6 amp. 220V ac rating. Why earth pin diameter is higher than other two pin? What its purpose ?

0 Answers  

For 7.5HP motor 2880rpm 415VAC Connected with Pressurisation Fan we used Star Delta Startor why not we use DOL startor

2 Answers   DLF,

How do I calculate/select Droop CT ratio for various capacity of generators?

0 Answers  

how to get electrical supervisor competency certificate in gujarat. i did 3 year diploma in electrical

0 Answers  

What are the causes ,revers rotation of a kwh meter?

2 Answers  

good morning sir, can u please tell me what type of questions asked in jindal so i can do my best in exam.

3 Answers