Three single-phase, 10-kVA, 2400/120-V, 60-Hz transformers are connected to a three-phase, 4160/208-V transformer bank. The equivalent impedance of each single-phase transformer referred to the primary side is 10 + j25 Ω. The transformer bank delivers 27 kW at 208 V and 0.9 power factor leading.

a. Draw the three-phase schematic diagram showing the transformer connection. Draw a per-phase equivalent circuit.
b. Determine the primary current and power factor.
c. Determine the primary voltage.
d. Determine the voltage regulation.

Your starship, the aimless wanderer, lands on the mysterious planet mongo. as chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 14.0 m/s returns to the ground in 5.70 s ; the circumference of mongo at the equator is 2.20×10^5 km ; and there is no appreciable atmosphere on mongo. (a) the starship commander, captain confusion, asks for the following information: what is the mass of mongo? (b) if the aimless wanderer goes into a circular orbit 2.20×10^4 km above the surface of mongo, how many hours will it take the ship to complete one orbit? (c) an unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 44.0 km . to the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s . if nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?