Engineering Board Exam Reviewer · Three-Phase Systems in Power Applications · easy
The balanced wye-connected load shown is supplied from a three-phase line of 240 V (line-to-line, rms). What is the voltage across each phase of the load?
- 240 V
- 416 V
- 120 V
- 139 V
Answer
D. 139 V
Solution
In a wye connection the phase voltage is the line voltage divided by 3: Vph=VL/ 3= 240 V 3=139 V.
More Three-Phase Systems in Power Applications questions
- A balanced three-phase resistive load is connected in delta. One of the three line wires opens. Compared with the original total power…
- In a balanced three-phase system with abc (positive) phase sequence, VAN=120 0° V. Find the line voltage VBC=VBN-VCN in polar form.
- The same three equal resistors are connected first in wye and then in delta across the same three-phase line. The total power absorbed in…
- A balanced delta load has Z =60+j45, in each phase and is supplied from a 400 V line. Replace the delta with its equivalent wye and find…
- A three-phase, four-wire wye system with a 120 V phase voltage (VAN=120 0°, VBN=120 -120°, VCN=120 120°) feeds the unbalanced resistive…
- The balanced load shown has Z=30+j40, in each phase and is wye-connected to a 400 V line. If the same three impedances are reconnected in…
- A three-phase generator is rated 1500 kVA at 4160 V (line-to-line). What is its rated line current?
- Three 10, resistors are connected in delta across a 240 V three-phase line. What is the line current?
- A balanced three-phase load of 100 kW operates at 0.8 power factor lagging. How many kvar of capacitors are needed to raise the power…
- In the two-wattmeter method on a balanced three-phase load, the wattmeters read 5 kW and 3 kW. What is the load power factor?