In a panel, I have following loads with respective power factor,
load A - 0.85
load B - 0.8
Load C - 0.9
How to calculate the Overall power factor of the panel, whether I have to take average or I have to consider the lowest?

Michael McCormick

• Nov 3rd, 2017

One needs to know the overall magnitude of each load in addition to power factor. Devolve each load into its real and imaginary components and add them vectorially.

murugan

• Nov 16th, 2016

Average(.85+.80+.90)?3=0.85 is answer

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When DC is applied, Transformer goes in to saturation, What happens if DC Pulses are applied, will this be safe? Will it act as transformer?

Pradeep Mewara

• Mar 29th, 2017

If we apply DC to the transformer, the nature of DC is constant magnitude so constant flux generate in primary winding there is no change in flux so EMF will not induce excepting when switch ON and switch OFF. If DC is continually supplied to the primary it will burn.

Ravi

• Mar 7th, 2017

When DC applied to Transformers the induced emf is zero in primary because of steady current, which leads to heavy current flow coz only coil resistance is connected directly to the source. Which dama...

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What is the difference between volage control device and Current control device

ENGINEER: ALJABRBI SALMAN

• May 3rd, 2020

A BJT is a current controlled device because its output characteristics are determined by the input current while a FET is voltage controlled device because its output characteristics are determined by the Field which depends on Voltage applied

M SIVARAJ

• Feb 27th, 2020

1.IN VOLTAGE CONTROL DEVICE VOLTAGE WILL BE CONSTANT & CURRENT WILL BE VARY
2..IN CURRENT CONTROL DEVICE CURRENT WILL BE CONSTANT & VOLTAGE WILL BE VARY.

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bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 9th, 2011

The core criteria for deciding rating of machine is LOSSES. while this may ultimately justify all the reason specified by above person. Because temperature rise of machine depend on losses. Insulatio...

raviiisc

 Profile Answers by raviiisc Questions by raviiisc

• Jun 9th, 2011

For any electrical equipment the power rating is decided by the thermal rating.orThe temperature withstanding capability of the machine.For generator the power rating depends on temperature, volume of rotor.

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For 63A load we can use 25/35sqmm cable. For same rating fuse conductor size is too low. How is it possible?(Its not depends on meterial, because single strand for above cable size is enough for fuse)

haveasafeday

 Profile Answers by haveasafeday Questions by haveasafeday

• Mar 24th, 2009

Generally Fuse is used for short circuit protection. That means it should be higher(normally 2 to 3 times of rated current depending on design) than other installation in a perticular circuit.

sindhejs

 Profile Answers by sindhejs Questions by sindhejs

• Feb 16th, 2009

As we know that fuse use for the safety purpose. And current will flow on the bases of resistance, as fuse?wire of small length (so it has lesser resistance), it can withstand 63A (as 25/35sq. mm cab...

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What measures will take for cost saving in utility and power generation

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 9th, 2011

POWER GENERATION 1. Try to increase "Diversity factor" as much as u can. 2. Try to increase "Load factor" 3. Try to decrease "Maximum demand" UTILITY : 1. Use Power factor improvement instrument lik...

Nishant Choudhary

 Profile Answers by Nishant Choudhary Questions by Nishant Choudhary

• Jun 3rd, 2011

The first thing always be remembered that for economical purpose the power factor should always be kept around unity or close to unity this u can do by avoiding light loads or by using APFC panels to improve power factor

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If 100w & 50w bulb connect in series and if we supply 440v then what happen, which one glow first?

veerateja

 Profile Answers by veerateja Questions by veerateja

• Dec 17th, 2010

The two bulbs will glow at a time bcoz the ckt should close the path through the second bulb also mean while the electricity(electron) speed is nearley equal to light speed.

srseshareddy

 Profile Answers by srseshareddy Questions by srseshareddy

• Sep 1st, 2010

Both glow at a time

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Why the brush is fitted in M.N.A axis? What is its effect on speed?

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 9th, 2011

Since reversal of current take places at MNA not at GNA, So, commutation can be improved by putting brush at MNA. Otherwise it leads sparking and damaging brushes and commutator. If load connected ac...

Nishant Choudhary

 Profile Answers by Nishant Choudhary Questions by Nishant Choudhary

• Jun 3rd, 2011

It does not effect the speed it is done to reduce sparking at the commutator contacts

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I mean which applications should require any of the above circuit breakers.

SGhosh

• May 23rd, 2012

MCBs have relatively low breaking capacity and sluggish compared to fuse. Fuse is used when cost of cable is a factor. If MCBs are used proper cable sizing must be done considering fault level and duration.

SPI

• Apr 24th, 2012

Fuse is old technology to break d circuit in fault. MCB is for low fault currents starting 6Amps to, 63Amps either 1Phase or 3Phase. And (b,c,d,k) are depends on the fault current and the location u r going to use. MCCB for higher currents more than 63 Amps that to in 3 Phase only.

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engineerfaisal

 Profile Answers by engineerfaisal Questions by engineerfaisal

• Mar 20th, 2009

Demand-side management (DSM) programs consist of the planning, implementing, and monitoring activities of electric utilities that are designed to encourage consumers to modify their level and pattern of electricity usage.

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Why can't the photo diodes produce large amperes of current? are there any large photo diodes producing current more than milli amps??

sameh

• Jun 28th, 2015

This is depend on the type and amount of the material that used in the diode to the materials used cant produce high current

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Why the capacitors are connected in delta? What advantage it having than star connection?

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 8th, 2011

Prime reason : Delta connection will give 3 times more reactive power(kVARs) than star connection.

there are few more reason....
1. less triplen harmonic
2. less heat loss, since current is I/1.732 where I will be the current star connection pr phase

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which is bigger in size AC or DC, of same rating?
As I think DC is right answer but HOW? Explain?

Pasupulati. V. N. Sekhar

• Jan 17th, 2012

The main difference in the size come because of the set up that is present in the DC machines i.e., in order to tap DC voltage generated we require the set up such as Commutator and brush arrangement ...

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Why many people do not connect the APFC/Capacitors in DC circuit?

KKMSURESH

 Profile Answers by KKMSURESH Questions by KKMSURESH

• Apr 8th, 2009

APFC means Automatic Power Factor Controller. Power Factor is applicable only in an AC Supply, DC is one of direct current, there is no Power Factor in DC Supply.

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shareek

• Nov 19th, 2007

firstly DIV means division. know 100V/DIV or 50A/DIV are usually the scales that are read on the OSCILLISCOPE. so if you see a waveform and you  have the scale set to 100v/DIV, it means that if y...

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s.v.vijayaraj

 Profile Answers by s.v.vijayaraj Questions by s.v.vijayaraj

• Apr 19th, 2008

           It is simple to find the teriminals in the SCR and Transistor, Where the SCR is in Flat package Transistor in metal can package.Also the th...

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s.v.vijayaraj

 Profile Answers by s.v.vijayaraj Questions by s.v.vijayaraj

• Apr 21st, 2008

Introduction Particle swarm optimization (PSO) is a population based stochastic optimization technique developed by Dr. Eberhart and Dr. Kennedy in 1995, inspired by social behavior of bird flocking o...

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Why people say that "When we want to send information (transfer from one pint to another) we modulate the signal below or above the center point (reference point)?1) By modulation we mean what?2. Why it is necessary to modulate signal for information center.3) Why more the modulation more informative can be send?

Eng. Maged saber

• Jan 17th, 2013

Modulation methods used because of when I need to transmit signal with low frequency it need long antenna as frequency inverse proportion with wave length and Wave length is in direct proportion with ...

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1-what is signal?2-What is Gsm?3-What about AMPS?4-What EDGE?5-What is GPRS?6-What is Ciphering?7-Difference Between Noise and Attenuation?

rahulr30

 Profile Answers by rahulr30 Questions by rahulr30

• May 30th, 2008

GSM-The Global System for Mobile Communications (GSM)GPRS-General Packet Radio ServiceEDGE -Enhanced DataRates for GSM Evolution

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What is Magnetic Levitation ?How MAGLEV (Trains based on Magnetic Levitation) works ?

arunkpkrn

 Profile Answers by arunkpkrn Questions by arunkpkrn

• Apr 15th, 2008

Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields. But train operating on Magnetic levitation is unknown to me.

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