A three-phase balanced star load No. 1 of (120 +j90) ohms in
parallel with another three-phase balanced star load No. 2 of (90
+j120) ohms, both are fed by three-phase balanced conductors of 3
ohms resistance and 4 ohms reactance. If the generator is 240
volts, with angle of -150° on phase c and reactance of 1 ohms,
determine: a) the current on load N°1 on phase C, b) the terminal
voltage of the generator on phase B, c) the...
A factory need a drive system for a conveyer system. Voltage
source available is three phase 415
Volt, 50 Hz. Electric motor that they use is DC motor.
(i) How the design of DC drive system for that system :
(ii) What the parameters should be considered?
(iii) What type of the DC motor that needed?
(iv) What kind of converters that suitable for this system?
(v) How the control system?
QUIESTION 1
A three-phase synchronous generator is connected to an infinite
bus. The infinite bus voltage and the generated voltage are o 1.0
pu ∠0 and o 1.0pu ∠42.84 , respectively. The synchronous reactance
is 0.85 pu and resistances are neglected. a) Compute power angle
(δ), armature current (Is), power factor (pf), real power (P), and
reactive power (Q). Draw the phasor diagram. b) If the prime mover
torque is kept constant at a value corresponding to P=0.8 pu,
compute...
A balanced three-phase delta-connected source has a line veltage
of 120 V. It is connected to a load via a three-wire transmission
line. The per-phase impedance of the delta-connected load is 30 +
120j (2. The impedance of each wire of the transmission line is 2 +
4j 2. How much power is dissipated by the load? By the transmission
line? What is the power factor of the load? What is the overall
power factor?
Two speakers spaced a distance 1.5 m apart emit coherent sound waves at a frequency of 680 Hz in all directions. The waves start out in phase with each other. A listener walks in a circle of radius greater than 1 m centered on the midpoint of the two speakers. At how many points does the listener observe destructive interference? The listener and the speakers are all in the same horizontal plane and the speed of sound is 340 m/s....
Two large, thin, metal plates of 0.5mx0.5m face each other. They
are spaced 2cm apart and have equal but opposite charges on their
inner surfaces.
a) if the magnitude E of the electric field between the plates
is 700 N/C what is the magnitude of the charge on each plate?
b) Integrate E across the gap between the plates to find the
potential difference V and hence the capacitance C.
c) Recalculate C using the parallel plate capacitator formula
instead....
You observe two point sources of light that are spaced 5 cm
apart which are each emitting light of wavelength of 420 nm. If the
diameter of your pupil is 2 mm, how distant can the objects be from
your eye for you to just barely resolve them?
A long, straight wire carries a steady current of 50 A. What is
the magnetic field strength at a distance of 7 cm from the
wire?
2. A capacitor consists of two metal plates, each 200mm by
300mm, spaced 9mm apart. The spaced between the metal plates is
filled with mica 6mm thick and a layer of paper 3mm thick. The
relative permittivity of the mica and paper are 9 and 6
respectively. Calculate: the i. capacitance and ii. electric field
strength in each dielectric in kV/mm due to a pd of 10kV between
the metal plates.