Answer / raghavendran

Drives can be classified as:

* Constant voltage
* Constant current
* Cycloconverter

In a constant voltage converter, the intermediate DC link
voltage remains approximately constant during each output
cycle. In constant current drives, a large inductor is
placed between the input rectifier and the output bridge, so
the current delivered is nearly constant. A cycloconverter
has no input rectifier or DC link and instead connects each
output terminal to the appropriate input phase.

The most common type of packaged VF drive is the
constant-voltage type, using pulse width modulation to
control both the frequency and effective voltage applied to
the motor load.

Answer / sandeep vazhoor

VVVF drives are generally classified into three types based
on the type of control philosophy adopted for motor control :
Ø Scalar control/PWM control
Ø Sensor-less vector control
Ø Vector control (with sensor) or Flux vector control

For flux vector control pulse encoder (or PG) will be
mounted on motor shaft as a feedback element.

why is the size of earth conductor is half of phase conductor.

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I have a question, I visit 01 site and face a problem, there is 2.5 ton Air Con working, when air con compressor is running at that time rectifier voltages are increasing upto 290-295 v and rectifier is giving main high alarm (rectifier is APC single phase), before starting compressor rectifier voltages was 230v. when air con is going off rectifier voltages are decreasing smoothly at its actual voltages 230v. Load on Genset phases is this: Red-13.5 amp AC (Air Con load), Yellow-1.7 amp AC (BTS lights etc.) and Blew-4 amp AC (telecom system load), Genset phase to phase and neutral to phase voltages are also ok. These are 10 sites having same system and same rectifier APC brand at every site 02 genset are working but the problem is same at all these 10 sites. What will be the reason behind???

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what is the difference between Resin Cast CT and Oil cooled CT?

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what is elevation lamp?where its used?

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What is the range of the stator resistance of 3 phase induction motor?

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0 Answers  

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