OFF-LINE UPS

Lower cost than other units
Under mains power unit charges batteries and power passes directly to the load
During mains failure batteries provide power to DC/AC inverter to provide 230VAC power to the load
Square-wave or Sine-wave output


ON-LINE UPS

Constant duty inverter
Design inherently improves power quality and...

in ac circuit what is return neutral , When its happenng & why ......

PRADEEP VERMA

• Dec 12th, 2014

Neutral link make a return path and make close path because current is flow in close path

anand bhavsar

• Nov 27th, 2014

I think its when neutral wire has got since your device is not getting neutral it will show voltage on its neutral terminal as well as circuit is incomplete.

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1)What is the latest generation of circuit breakers called?

2)What are the special cables required for explosion proof wiring?

3)What are the different types of soft starters for large motors?

4)What is the similarity and what is the difference between relays and PLC?

priyobrato

• Dec 7th, 2014

Relay can be used as potential free dry contact,with less switching speed cause its a electro mechanical device .PLC has better switching speed.BOTH are controlling device.

Chakry

• Nov 30th, 2014

The cables used in Inflammable and explosive situations should be Mineral insulated Copper sheathed complying with BS 6207.

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anand bhavsar

• Nov 27th, 2014

Body earthing is use to ground the potential that gets on body of equipment if theres shot circuit or any fault in quipment (motor winding getting shot with motor body), in order to protect humans fr...

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vishnu sharma

• Nov 27th, 2014

Catch the wire from both hands at a time in air, then potential difference is zero, so that current does not flow in body.

Santanu

• Jul 10th, 2013

There is no risk of any shock as the whole body is at same potential. However, if the persons body touches ground or for that matter, anything which may create a potential difference, there will be el...

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What is the difference between phase and neutral?

sarita

• Nov 16th, 2014

Phase contain supply voltage i.e heavy electrons or protons and neutral contain no supply voltage and neutral charges.

saadsms

 Profile Answers by saadsms Questions by saadsms

• Oct 26th, 2014

1- in one phase case : Phase is supply voltage weather neutral is returning path the same current for that supply voltage. 2- in three phase case : - in balanced load current returned to earth = 0 - ...

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Describe how high currents and voltages are measured with the help of instrument transformer?

Trushar Upadhyay

• Nov 15th, 2014

Current measured by ct and Voltage measured by pt

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What is the suitable cable for fire alarm system

Techguru

• Nov 15th, 2014

Three types of power-limited fire alarm cables are currently in use. These are: FPL, FPLR and FPLP. Type FPL power-limited fire alarm cable is listed by the NEC as being suitable for general purpose fire alarm use.

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How size of UPS depends on frequency? I mean proportional, inversely proportional or proportional to square of frequency?

Umair Anwar

• Nov 13th, 2014

Because core size of transformer directly depend on frequency and transformer primary element.

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 8th, 2011

Actually i mean SMPS not UPS.

Please moderator, if you can change my question please do it.. Replace UPS by SMPS since i didn't get any option to edit my question

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In meters with electromechanical " rotating disk " What is the difference between the meter of reactive powerVARHM and the meter of active power WHM.??
Working theory and internal structure.??
Thanks

sanat kumar patro

• Nov 5th, 2014

Active power is that power which is converted to other form of energy like heat,mechanical etc.But reactive power is that power which doesn't take place in energy conversion but is used in magnetization of winding for producing magnetic fields.

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sanjay yadav

• Oct 25th, 2014

Current is the electron motion through external force. ? ? ? ? ? ? ?External force is applied voltage.

lalit

• Sep 27th, 2014

Voltage is the driving force that causes the current to flow in the closed path of the circuit. so if there is no voltage , there would be no current in that part of the circuit across the element

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What is meaning of "Motor Frame Size"? What is use to determine the motor H.P?

ashish srivastava

• Sep 29th, 2014

This means the distance between the horizontal center axis of motor and ground.

sindhejs

 Profile Answers by sindhejs Questions by sindhejs

• Feb 18th, 2009

For the coupling (motor to any other devices) purpose the motor frame come into picture. Its very important to match the frame size, otherwise motor may damage. To calculate the motor rating, it is required to have motor voltage rating and current rating.

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Why SC test is performed on LV side?

Umesh

• Sep 25th, 2014

We generally performs Short circuit test keeping initial voltage at lower value and then gradually increases it up to the level to get a full load current (or Max) through testing device or circuit. B...

KM Mahesha

• Jul 22nd, 2014

Load are in LV side and also max SC faults occurred in Load side. If SC Faults occurs protect load and Net work system

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roshan kumar jha

• Sep 24th, 2014

Coz of form factor generally

kumar sundram

• Sep 19th, 2014

If you notice that 765,1200,400kv is always assumption based questions not in reality.But any practical point of view it is always multiple of 11 because of form factor dear.

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prasad jandhyala

• Sep 6th, 2014

Synchronous motor acts as a condenser when it is operated at no load and over excited state. synchronous condensers are mainly used for power factor improvement.

Pramod kumar

• Sep 3rd, 2014

Synchronous motor behave as a condenser when it uses at no load and leading pf.

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Hello sir/madam,
I have completed BE in electrical with 65% aggregate.Even after trying for many jobs I didnt get desired job so currently am working in BPO sector. so suggest me to get good job related to my educational background please....

sudhir

• Jul 29th, 2014

Learn Electrical Design.

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liyakath shaik

 Profile Answers by liyakath shaik Questions by liyakath shaik

• Jul 24th, 2014

the ?frequency ?is ?depends ?on ?speed ? synchronous ?speed= 120f/p ?from this ?we ?know ?that f= Np/120 in ?india ?speed ?of alternator is ?nearly ?about ?3000 ?rpm ?and ?the ?p...

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What is shape of the coils used in a transformer ? choose the correct one from the bracket (rectangular,oval,circular,cylindrical ) & justify it with detail reason.

Is transformer a machine ?choose the correct one from the bracket (yes/no) & justify it with detail reason.

manikandan.l

• Jul 18th, 2014

Rectangular

AlHussein Abdallah

 Profile Answers by AlHussein Abdallah Questions by AlHussein Abdallah

• Jul 17th, 2014

Star connected rotor of induction motor has a standstill impedance of (0.4+4j)ohm per phase and rheostat impedance per phase is (6+2j)ohm. The motor has induced voltage of 80v between slip-rings at st...

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If we take the winding displacement as 180 degrees in 2 phase winding what will happen?

Himang

• Jun 9th, 2014

Non uniform torque will be produced which would make the operation noisy.

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Though transformer consist winding which usually cause reactive power change in both generator and motor but it wont affect reactive power passing through transformer why?

Dnyanesh

• Jun 7th, 2014

In rotating motor, power factor can not be maintain at unity bcz these all are inductive, but in case of transformer, we can maintain the power factored at unity, and whenever pf is unity, there will be zero reactive power

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