EET 390 Unit 5 Review Chapter 20

 20-5 If the start and stop pushbuttons in Fig. 20.24a are pushed simultaneously, what willhappen? 

 20-11Referring to Fig. 20.39, calculate the mechanical power [hp] of the motor when it runs at450 r/min .

Figure 20.39

 20-23Referring to Fig. 20.39 and neglecting windage and friction losses, calculate the power Prsupplied to the rotor when the machine runs 

 a. As a motor at 1650 r/min
 b. As a brake at 750 r/min
 c. As a generator at 2550 r/min
 

 Chapter 21:
 21-9The chopper shown in Fig. 21.62 is connected to a 3000 V dc source. The chopperfrequency is 50 Hz and the on-time is 1 ms. Calculate 

 a. The voltage across resistor R0
 b. The value of IS if R0 = 2 Ω