Chapter 14, Problem 4QAP

Homework#5

Two loads connected in parallel are respectively 2 kW at a pf of 0.75 leading and 4 kW at a pf of 0.95 lagging. Calculate the pf of the combined two loads. Find the complex power supplied by the source. Hints: • • Since the two loads are parallel, the complex power, S, supplied by the source is S = S₁+ S₂ Calculate the complex powers, S₁ and S2, of each load (use power triangles) and add them to find the total S. Calculate 0 and obtain pf.

A 3-phase, 20-pole induction motor is con- nected to a 600 V, 60 Hz source. a. What is the synchronous speed? b. If the voltage is reduced to 300 V, will the synchronous speed change? c. How many groups are there, per phase?

Describe the principle operation of PEMFC, and role of membrane electrode assembly (MEA).

Starting from Maxwell’s equations derive the Kirchohf’s circuit laws for voltage and current. Clearly mention what approximation is used for this derivation.

In the control system shown in Figure Q4(a), G₁(s) = and G₂(s) == If the system has the specifications for the natural frequency and dampingratio of -5 rad/sec and {=0.7, respectively, determine K and H,(s) when H₂(s) = 1.

Can the expert help me draw a curve on my graph paper? TERMINAL VOLTS 9000 8000 7000 6000 5000 4100 4000 14 18 22 26 30 34 38 FIELD AMPERES, If OPEN CIRCUIT CHARACTERSTICS Fig 3 42 42 46 50 54

Homework#5

Solve this problem and show all of the work