• #### 3Phase rectified to single phase

If I got a 380v 3-phase supply and I want to rectify it with thyristors to single phase how much voltage will I get ?What is the relationship?thanks

#### SGhosh

• May 15th, 2012

The dc output of the full wave rectifier is average value the amplitude of the sine wave. In short multiply the r.m.s value of the ac input voltage by its form factor (1.11 in case of pure sine wave) ...

#### mahmoudp1

• May 15th, 2012

I know the output will be dc my question is how much dc voltage will be the output

• #### Induction Motor Power Factor

A 3-phase induction motor running on 500v at full load draw 40A current at 0.85 pf Lagging if 85 micro Farad capacitor connected across its terminal than what would be a New Power Factor?

#### mahmoudp1

• May 1st, 2012

You didn't specify the capacitors connection is delta or star
assuming (delta)
Xc = 37.462 ;
reactive power drawn by capacitor = 6684.49 VAR
active power drawn by motor = 34641 watt
old power factor = .85 lag
new power factor = .91 lag

#### vishnu

• Feb 18th, 2012

--> Find the reactance offered by capacitor i.e 37.46 ohm. so leading current drawn by capacitor is 9.095A @90 deg lead. --> Current drawn by the motor is 40A @ 31.788 deg lag. --> Resultant current ...

#### soomnath paul

• Feb 2nd, 2013

High resistance is connected in order to make the voltage appeared across the pressure coil in phase with the applied one.

#### mahmoudp1

• May 1st, 2012

We connect more resistance in series to make the total resistance is high so that it wont absorb any power (amperes) for the circuit so i wont affect on the true reading and also the series coil to me...

• #### Induction Motor selection

Could you explain that how to select an induction motor for a specific mechanical load(inertia). is there any formula or calculation then please give me. i shell be very thankful to all of you.

#### mahmoudp1

• May 3rd, 2012

First know the load specifications like power needed or torque and from the catalogues choose the correct motor without any calculations.

• #### Calculation of Electrical Cable size

Will u please give the formula, for selection of cable sizing (both Copper and Aluminium) depend upon the electrical loads...

• Mar 24th, 2014

CABLE SIZING FORMULA:-2 *L * I/(K*Vd) ...............FOR SINGLE PHASE LEGEND:- I :- LOAD CURRENT =160 AMPS L :- LENGTH OF THE CABLE = 200 METERS K :- CONDUCTIVITY OF COPPER = 58 AND CONDUCTIVITY OF...

#### mahmoudp1

• May 3rd, 2012

It depends on a lot of factors like current density for mm^2 temperature is the cable on cable trays or buried or inclosed in PVC is that a 3 phase cable multicore or what and also depends on the voltage but in general making a current density 2 A/mm^2 for copper for simple applications is good.

• #### Induction Stove

As all we know,induction stove works on the principle of electromagnetic induction.Thus an emf is induced in the vessel and eddy current flows through the vessel.Since the vessel is made of ferromagnetic material (high resistivity) larger amount of heat (H=I^2 R)is generated.What will happen if a human body comes into contact with this high resistive vessel??? Won't the human body resistance be parallel...

#### SGhosh

• May 15th, 2012

Human body under dry condition has much higher resistivity compared ferromagnetic material.

#### mahmoudp1

• May 5th, 2012

Ferromagnetic material is higher

• #### Three Phase Transformers

A 3phase wye/delta transformeris rated 225kV/24kV, 400MVA and has a series reactance of 13.3ohms as referred to its high voltage side. The transformer is supplying a load of 325MVA at 0.9 pf lagging at a voltage of 24kV(line to line)on its low voltage side. It is supplied from a feeder whose impedances are (0.15+j1.5)ohms connected to its high voltage terminals. For these conditions calculatea> The...

#### mahmoudp1

• May 10th, 2012

???
incorrect information
you should specify at least on of the terminals voltages

• #### Phase Conversion

List various methods to convert 1 phase to 3 phase.

#### mahmoudp1

• May 14th, 2012

This can be done with thyristors

#### raviiisc

• Sep 8th, 2010

This conversion is done by using mainly two methods. They are:1. Convert 1-ph ac to dc by using power electronic converter then convert that dc to 3-ph ac using power electronic inverter using PWM...

• #### Distribution Tower

What types of tower & pole is used in power system distribution?

#### mahmoudp1

• May 14th, 2012

For lattice metal structure (High Voltage )
they can divided into (specifying the job)
suspension , angle , end , cross towers

#### raviiisc

• Sep 8th, 2010

I think "_punjabi_" forgot about the concrete poles or towers.These towers are more practical in now a days in Power distribution sector.

• #### Electrical Machine Operation

In a 50hz electrical machine what happens when we use more than or less than 50hz?

#### mahmoudp1

• May 14th, 2012

Frequency affects on the speed and torque of the machine and thats is the principle of the drives

#### _punjabi_

• Aug 29th, 2010

Speed and torque of the Electrical machines can be regulated by chanigng the supply frequency. Also harmonics produced are different than normal operation

• #### OC/SC Test On Low Voltage Side

Why OC test is carried out on low voltage side of transformer?

#### mahmoudp1

• May 3rd, 2012

The previous answers are right + to make an accurate measurement O.C test on LV side because the current is high on the low voltage so when we repeat the experiment we will get more results with the ...

#### Pratyush Singh

• Jul 26th, 2011

Because during OC test, rated voltage is applied, hence the HV side is unsuitable to keep instruments, hence it is the HV side that is opened and the LV side is where instruments are placed (at their rated values)

• #### Transformer Voltage Regulation

Which of the following test are to be conducted for the determination of voltage regulation of a transformer.a. Load Testb. Short Circuit Testc. OC Testd. Retardation Test.

#### SUBHABRATA BASAK

• Oct 9th, 2017

B. Short Circuit Test

#### SUBHABRATA BASAK

• Oct 9th, 2017

SC Test Only... But also need to know about PF of the Load as V.R. of transformer depends on PF of Load

• #### DC Voltage Control

How we can step-up or step-down the DC voltage directly?

#### S.Ghosh

• May 23rd, 2012

A chopper is nothing but a thyristor/SCR/transistor circuit which operates with the principle of PWM (Pulse Width Modulation). If you need to boost DC voltage with chopper, additional circuits includi...

#### sai charan

• May 20th, 2012

this can be done by using chopper.chopper is a dc equivalent of a.c transformer to which d.c input which is to be stepped up is applied at input terminals and output is taken from output terminals whi...

• #### Circuit Breaker

Explain what are Single and 2 Pole circuit breaker?

#### mahmoudp1

• May 1st, 2012

Yes and single pole means that circuit switch two poles / two wires (eg; live and neutral)
3 poles used to switch 3 phase systems
4 poles used to switch 3 phase + neutral wire
5 poles used to switch 3 phase + neutral + ground wire

#### amolgaonkar

• Dec 9th, 2011

Circuit Breaker is a safety device used to safeguard electrical equipments from heavy current, it trips OFF when more than rated current passes through it.

• #### Q-point in transistor?

What is the purpose of Q-point in transistor?