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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Advantages of 3 phase |
Over single phase.. |
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1. Has greater....... |
Output than single phase |
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2. Work in......... |
Parallel without difficulty |
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3. Requires much less...... |
Conductor than 1 phase transmission line |
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4. Possess uniform....... |
Torque (as opposed to 1 phase pulsating torque) |
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5. Self-......... |
Starting |
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6. Never falls........ |
To zero |
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7. More........ |
Compact (1 phase requires more space) |
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8. Much higher..... |
Efficiency |
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Star and delta connection |
Star connection |
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Line voltage (Vl) |
Root(3)*Vph |
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Line Current (Il) |
Iph |
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Power (P) |
Root(3)*Vl*Il*cos(#) |
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Two Wattmeter Method |
W=W1+W2 |
Measuring power of three phase system |
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For Wattmeter W1 |
Parameters (Current, Voltage, Power) |
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Instantaneous Current (I) |
iA |
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Instantaneous Voltage (eAC) |
eA-eC |
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Instantaneous Power (W1) |
iA(eA-eC) |
Similar for W2 |
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Total instantaneous power (W) |
W1+W2 = iA(eA-eC)+iB(eB-eC) = iAeA+iBeB-eC(iA+iB) |
iA+iB+iC=0 = iAeA+iBeB+iCeC =Pa+Pb+Pc |
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Additional formulas: impedence (Z) |
Resistance(R)+Inductance(L)j |
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