The production of an induced voltage requires a conductor (generally in the form of a coil), a magnetic field, and ____ motion between the two.
a. transient
b. nonpolarized
c. static
d. relative
d. relative
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?When inspecting valves from the valve body: Technician A says the edges of the spools should be damage-free but should not be sharp.Technician B says to identify a bent valve, install it into its bore and rotate it. If it binds or drags while it is being rotated, it is bent.Who is correct?
A. ?A only B. ?B only C. ?Both A and B D. ?Neither A nor B
A plumb bob is used to determine a ____________________ line
Fill in the blank(s) with correct word
An ideal gas has CV* = 4R. What is the change in entropy of the gas when 25 moles of the gas is compressed isothermally from 0.1 MPa to 0.8 MPa at a temperature of 350 K?
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A dc, separately excited motor is used to drive a constant-torque load. The field circuit is excited by a full-wave, ac/dc SCR converter. The armature circuit of the motor is connected to a constant dc voltage source of 160 V. The inductance of the field circuit is large, and the field current is always continuous. The ac voltage (input to the converter) is 120 V (rms), and the field resistance is 100 ?. The armature resistance is 2 ?. When the triggering angle of the SCRs is adjusted to zero, the motor speed is 1200 rpm, and the armature current is 10 A.
a. Calculate the average current and dc power of the field circuit when the triggering angle is equal to 20o. b. Calculate the rms voltage across the field windings for the condition given in (a). Explain how the rms voltage is dependent on the triggering angle. c. Calculate the no-load speed of the motor. Ignore the friction and windage losses. d. Calculate the triggering angle to operate the motor at a speed of 1400 rpm. e. Can you use the field converter to reduce the motor speed to 1000 rpm? How?