Question

1. Under the hood of the Toyota Camry your instructor owns are two fans that are used to cool the air conditioning condenser and cooling system radiator. These fans are connected in series when the refrigerant pressure in the air conditioner is below 200 psig (only light to moderate cooling is needed), and are connected in parallel when the refrigerant pressure is higher than about 210 psig (occurs on a hot day when lots of cooling is needed and car is stopped or moving slowly). Assume for today that each fan motor has a constant resistance of about 3.5Ω (actually a bad assumption, but we’ll talk about that in a later class). Further assume that when the engine is running, the alternator that recharges the battery and supplies power to the car’s electrical systems supplies a voltage that is constant at about 14 V.D.C. How many amperes flows through each motor in each of the two scenarios listed above?

Answer 1

Given Conditions are I when refrigant pressure is less than 200 psig the ans are connected in series in when pressure is above 210 psig the fans are Connected in parallel. Alternator supplies constant 14VDC in both cases consider case (): in fans Fani are connected Fan series Given each fan motor resistance = 3.50 + 14V. DIT I = 14 13 435 3.5+ 3.5 II = 2A fans are flows through each fan motor connected in parallel Case il 14 V (& fanz 3.5 Fan! 3.5

Each fan motor Current - 14 3.5 Each fan motor Current = 4A