Answer / rahul

3 Phase 4 wire means 3 phases R,Y,B and a neutral, so it is usually used if you need a single phase voltage. For a 3 phase load need just 3 phase 3 wire system.

Answer / sharaf

yes...an extra earth wire in 3 phse 4 wire systm protects
equipments frm earthing

Answer / suraj chawardol

We should have clear concept regarding where 3 phase 3 wire system used and where 3 phase 4
Wire system used
1.3 phase 3 wire system= In India electrisity is generat at 11 or 33 kv.then it is step up with the help of tranformer. To transfer it from generation station to substation 3 phase 3 wire system is used. Then it is step down at substation or directly feed to application having such rating. Genarally 11 kv feeder are brought near to distrubution transformer near to load ( near to home genarally called DP). The input to distribition transformer is 11 kv feeder and output of transformer is 440 v , 3 ,phase 4 wire system. ie 3 phase R,Y,B and one neutral.
2. 3phase 4 wire system = the secondary side of transformer is star connected so line voltage become 1/sq root 3, ie near 240 v . Our home appliances are design to work at Approximataly 230 v ,50 hz so we need any one phase and neutal for single phase load .
3. Also for high power application we need 3 phase 3 wire system such as Induction motor.
4. Both the system have its own importance depending on applications.

Answer / ashok mishra

question is which one is more reliable??

Why does increasing the magnetic flux in the main field of a d.c motor cause the armature current to reduce??

0 Answers  

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Is RTCC panel needs any control supply.

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if there are six generators (3 gas CATT, one Jenbacher o1 MW each, and two nos Diesel 01 no 01 mw other 0.65mw EDGs ( say), 3 CAtt gas set have identical pole pitch,01mw EDG and Jenbacher gas Set have different pole pitch, how their power connection can be done to connect a common bus bar during installation. in short, how different pole pitched generators power connection can be done to connect a common busbar system through generators incomer ACBs.

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Give the topology of current amplifier with current shunt feedback?

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My switchgear busbar is rated at 2000A and just imagine the actual load on busbar is 1000A. From that busbar there are 10 outgoing feeders. Now the question is will the load be 1000A on each outgoing feeder or 100A per outgoing feeder. 2nd thing how do i calculate the load on individual feeder. Thanks for your time. Please provide some clarification on this issue.

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All the voltage drops and the source voltage added together in a series circuit is equal to

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For the same power rating,which motor is bigger in size,AC or DC?

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State the function of control rods used in nuclear reactor

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I HAVE A INCOMING 100A MCCB TPN 25KA, CABLE LENGHT OF 80M 70MM CABLE SIZE FROM MAIN SUBBOARD TO NEW DB.BASE ON THE FAULT LEVEL SETTING OF 45KA.I WOULD LIKE TO FIND OUT 25KA ENOUGH KA. APPRECIATE IF SOMEBODY CAN ASSIST ME WITH FORMULA FOR THIS. FRM: JEFF

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Can I use RCCB in moisture control device in a submersible pump.

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