Star To Delta Conversion Solved Problems Pdf 40

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These circuit transformations allow us to change the three connected resistances (or impedances) by their equivalents measured between the terminals 1-2, 1-3 or 2-3 for either a star or delta connected circuit.

However, the resulting networks are only equivalent for voltages and currents external to the star or delta networks, as internally the voltages and currents are different but each network will consume the same amount of power and have the same power factor to each other.

To convert a delta network to an equivalent star network we need to derive a transformation formula for equating the various resistors to each other between the various terminals. Consider the circuit below.

When converting a delta network into a star network the denominators of all of the transformation formulas are the same: A + B + C, and which is the sum of ALL the delta resistances. Then to convert any delta connected network to an equivalent star network we can summarized the above transformation equations as:

If the three resistors in the delta network are all equal in value then the resultant resistors in the equivalent star network will be equal to one third the value of the delta resistors. This gives each resistive branch in the star network a value of: RSTAR = 1/3*RDELTA which is the same as saying: (RDELTA)/3

The transformation from a Star network to a Delta network is simply the reverse of above. We have seen that when converting from a delta network to an equivalent star network that the resistor connected to one terminal is the product of the two delta resistances connected to the same terminal, for example resistor P is the product of resistors A and B connected to terminal 1.

By rewriting the previous formulas a little we can also find the transformation formulas for converting a resistive star connected network to an equivalent delta network giving us a way of producing the required transformation as shown below.

By dividing out each equation by the value of the denominator we end up with three separate transformation formulas that can be used to convert any delta resistive network into an equivalent star network as given below.

One final point about converting a star connected resistive network into an equivalent delta connected network. If all the resistors in the star network are all equal in value then the resultant resistors in the equivalent delta network will be three times the value of the star resistors and equal, giving: RDELTA = 3*RSTAR

Both Star Delta Transformation and Delta Star Transformation allows us to convert one type of circuit connection into another type in order for us to easily analyse the circuit. These transformation techniques can be used to good effect for either star or delta circuits containing resistances or impedances.

It is a three phase generator, each phase supplies 167/3 = 56 kVA. Assuming delta connected, the line voltage is across each phase and the current is 56,000/240 = 230 A. If it is star connected than the phase voltage is 240/sqrt(3) = 138 V and the current is 56,000/138 = 400 A. The three phase calculator may also help you:

In general when connecting in delta you have a higher voltage on each leg, so I would say you consume more power. I try not to think like that as it confuses me as well and there is sometimes more to it than that. My advice would be to look at your actual situation and analysis it to see the effect of changing from star to delta. Also be aware that if draw more power, you equipment may not have been designed for it.

1. Find the equivalent delta circuit.a) 9.69 ohm, 35.71 ohm, 6.59 ohmb) 10.69 ohm, 35.71 ohm, 6.59 ohmc) 9.69 ohm, 34.71 ohm, 6.59 ohmd) 10.69 ohm, 35.71 ohm, 7.59 ohmView AnswerAnswer: aExplanation: Using the star to delta conversion:R1 = 4.53+6.66+4.53*6.66/1.23 = 35.71 ohmR2 = 4.53+1.23+4.53*1.23/6.66 = 6.59 ohmR3 = 1.23+6.66+1.23*6.66/4.53 = 9.69 ohm. var adpushup = window.adpushup = window.adpushup || {}; adpushup.que = adpushup.que || []; adpushup.que.push(function() { adpushup.triggerAd("9f8aa9b5-2c42-4296-896e-70772ed1db59"); }); 2. Which, among the following is the correct expression for star-delta conversion?a) R1=Ra*Rb/(Ra+Rb+Rc), R2=Rb*Rc/(Ra+Rb+Rc), R3=Rc*Ra/(Ra+Rb+Rc)b)b) R1=Ra/(Ra+Rb+Rc), R2=Rb/(Ra+Rb+Rc), Rc=/(Ra+Rb+Rc)c) R1=Ra+Rb+Ra*Rb/Rc, R2=Rc+Rb+Rc*Rb/Ra, R3=Ra+Rc+Ra*Rc/Rbd) R1=Ra*Rb/Rc, R2=Rc*Rb/Ra, R3=Ra*Rc/RbView AnswerAnswer: cExplanation: After converting to delta, each delta connected resistance is equal to the sum of the two resistance it is connected to+product of the two resistances divided by the remaining resistance. Hence R1=Ra+Rb+Ra*Rb/Rc, R2=Rc+Rb+Rc*Rb/Ra, R3=Ra+Rc+Ra*Rc/Rb.3. Find the equivalent resistance between X and Y.a) 3.33 ohmb) 4.34 ohmc) 5.65 ohmd) 2.38 ohmView AnswerAnswer: dExplanation: The 3 2ohm resistors are connected in star, changing them to delta, we have R1=R2=R3= 2+2+2*2/2=6 ohm.The 3 6ohm resistors are connected in parallel to the 10 ohm 5 ohm and 10ohm resistors respectively.This network can be further reduced to a network consisting of a 3.75ohm and 2.73ohm resistor connected in series whose resultant is intern connected in parallel to the 3.75 ohm resistor. Subscribe Now: Basic Electrical Engineering Newsletter | Important Subjects Newsletters advertisement var adpushup = window.adpushup || {}; adpushup.que = adpushup.que || []; adpushup.que.push(function () { if (adpushup.config.platform === "MOBILE") { adpushup.triggerAd("e5da93a0-b61a-4789-96be-a57ebec165b0"); } else if ((window.outerWidth

In transformer primary is delta connection and secondary is star connection , the primary v1=110kv ,v2=22kv and power is 16 mva how to calculate current i1 and i2, If im using the formual p= 3*vph*iph*cos fi what is the value of cos fi

However, in some situations, it is difficult to simplify the network by following the previous approach. For example, the resistors connected in either delta (Î´) form or star form. In such situations, we have to convert the network of one form to the other in order to simplify it further by using series combination or parallel combination. In this chapter, let us discuss about the Delta to Star Conversion. 2b1af7f3a8