Three resistors are connected in a DELTA configuration and the phase voltage is 400V/ 50Hz. What is the line to line vol

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Three Resistors Are Connected In A Delta Configuration And The Phase Voltage Is 400v 50hz What Is The Line To Line Vol 1 (34.21 KiB) Viewed 40 times

Three Resistors Are Connected In A Delta Configuration And The Phase Voltage Is 400v 50hz What Is The Line To Line Vol 2 (31.29 KiB) Viewed 40 times

Three Resistors Are Connected In A Delta Configuration And The Phase Voltage Is 400v 50hz What Is The Line To Line Vol 3 (23.61 KiB) Viewed 40 times

Three resistors are connected in a DELTA configuration and the phase voltage is 400V/ 50Hz. What is the line to line voltage and the line current when each resistor has a value of 20 ohms? a. 400 V and 34.6 A b. 230 V and 20.0 A c. 400 V and 20.0 A d. 230 V and 34.6 A What is a three-phase transformer? a. A three-phase transformer is constructed by winding three single-phase transformers on three individual core. b. A three-phase transformer is constructed by winding three single-phase transformers on 4 cores. c. A three-phase transformer is constructed by winding three single-phase transformers on 2 cores. d. A three-phase transformer is constructed by winding three single-phase transformers in series. A three-phase distribution transformer has a tapped primary winding and a fixed secondary winding. If the transformer's output voltage is low what can be done to correct this fault? a. connect to a lower the voltage tap connect to a higher the voltage tap b. C. nothing can be done d. none of the above A 900kVA single phase transformer has a rated full load secondary current of 1500A. The transformer's impedance is 4%. What is the maximum short-circuit current at the secondary side? a. 37.5kA b. 20.0KA C. 0.37KA d. 10.0KA
5. A 60KVA, 600V/208-120V 3-phase transformer is to be connected to a breaker panel. Calculate the secondary line current of the transformer. Hint: (Determine Y or A) a. 288.5 A b. 20.0 A C. 166.5 A d. 100 A 6. One phase of a 208V DELTA configured secondary is accidently grounded due to a fault in a coil. What is the voltage of the other two phases with respect to ground? a. 208 V b. 120 V C. OV d. 60 V 7. The ratio of real power [W] to total power [VA] is called power factor. At what P.F. performs the equipment at the best? a. PF between 80% and 90% b. PF between 90% and 100% C. PF exact at 50% d. PF between 0% and 10% Name two benefits of improving the power factor. a. - Improve energy efficiency of the electrical system. - Reduce electricity bills by eliminating power factor surcharges. b. - Enhance equipment operation. - Conductors may be select with a larger cross-sectional area. - Eliminate transformer maintenance. - Upgrade the transformer to higher power output. - Reduce electricity bills. - Eliminates Grounding and Bonding. C. d.
9. You have determined that a facility has a poor factor. Name two reasonable places where to start the investigation. a. - Harmonics caused by non-linear loads. - Basement of the facility. -Large fans and motors (especially partial loaded). - Equipment with a high number of inductors (lighting ballast). - Improper sized capacitor for power factor correction. - On the roof of the facility. - On the roof of the facility. - In the basement of the facility. 10. The schematic to the right shows a parallel circuit of RLC connected to a 120V/60 Hz source. Calculate the total current Is wher: R=10 Q. L=10mH, and C = 470 uF. a, 1 16A b. I=12 A C. 1= 31.8 A d. 1=21.2 A b. d. ww