a. Referring to fig 22.18a, calculate the average current and also the peak current carried by the freewheeling diode.

b. What is the PIV across the diode?

Figure 22.18a

Problem 22-13

In Problem 22-12 (and referring to Fig, 22.9), if the same mass is lowered at a constant speed of 100 ft/min, calculate the following:

a. The armature current and its direction

b. The value of and its polarity

c. The value of and its polarity

d. In which direction doe~ the active power flow in the ac line?

figure 22.9

Problem 22-12

The hoist motor shown in fig 22.9 is lifting a mass of 5000 Ib at a constant speed of 400 ftlmin.

a. Neglecting gear losses, calculate the value of Eo if the armature current Id is 150 A.

b. Knowing that R_{a} = 0.1 Ω, calculate the value of converter voltage E_{d}

figure 22.9

Problem 22-14

In Problem 22-12, if the mass is simply held still in midair, calculate the following:

a. The value of Eo

b. The armature current lei

c. The value and polarity of Ed

problem 22-12

The hoist motor shown in fig 22.9 is lifting a mass of 5000 Ib at a constant speed of 400 ftlmin.

a. Neglecting gear losses, calculate the value of Eo if the armature current Id is 150 A.

b. Knowing that R_{a} = 0.1 Ω, calculate the value of converter voltage E_{d}

figure 22.9