A fluid coupling of the type shown in Figure 19.10 has its input and output shafts directly coupled to an electric motor and driven machine, respectively-see Figure P19.26. The motor and coupling characteristics conform to the performance curves in Figure 19.11.
(a) During normal operation the motor rotates 1780 rpm and drives the machine with 55 percent of its rated power. What is the rotating speed of the machine input shaft? What percent of the motor torque reaches the machine? What percent of the power output of the motor is converted into heat in the fluid coupling?
(b) How much does the coupling slip during overload operation requiring full-rated motor power?
(c) If the machine is overloaded to the point that the motor cannot drive it and the machine stops, what is the motor rpm? Under these conditions, what fraction of normal rated motor power is converted into heat in the fluid coupling?
