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ELECTROTECHNOLOGY
ELTK1200
ASSIGNMENT #3
1.
Determine the inductive reactance of a 5.5 mH choke at 25 kHz.
2.
(a)
(b)
3.
When an inductor is connected to a 24V, 60 Hz supply, a current of 40 mA flows.
Determine the inductance of the coil.
4.
A voltage of
V is applied across a purely inductive load with a reactance
of 86. Determine the resulting current.
5.
The instantaneous voltage across a 25 mH choke is
Determine the instantaneous current when t = 10 ms.
6.
Two inductors, L1 = 200mH and L2 = 250mH, are connected in series to a 24V, 60Hz
ac supply. Determine:
(a)
the total inductive reactance.
(b)
the total current.
(c)
the voltage drop across L1.
(d)
the voltage drop across L2.
7.
Two parallel-connected inductors, L1 = 1.2H and L2 = 1.6H, are connected to a
208V, 50Hz ac supply. Calculate:
(a)
the total inductive reactance.
(b)
the current through L1.
(c)
the current through L2.
(d)
the total current in the circuit.
8.
A 25mH coil and a 2006 resistor are connected in series to a 24V, 1kHz supply.
Calculate:
(a)
Impedance.
(b)
Current.
(c)
Phase angle.
(d)
Voltage across resistance and inductance.
(e)
Draw a phasor diagram showing VR, VL, VT, and I (as reference) for the
circuit.
(f)
Draw an impedance triangle showing R, XL, Z and for the circuit.
ELTK1200
If the reactance of a coil at 60 Hz. is 3350.16, determine the inductance.
What will the coil’s inductive reactance be at 50Hz?
Marine Institute
Rev 2
.
117
9.
A current of 2¬0° A flows through a series RL circuit. The voltage drop across the
resistor is 50V and the voltage drop across the inductor is 62.83V. If the frequency
of the source is 90Hz., determine the instantaneous value of the source voltage at
7.5ms.
10.
When connected to a 120V, 60Hz source, the phase angle for a series RL circuit is
30° (lagging) and the current is 2A. Calculate:
(a)
Voltage drop across the resistor.
(b)
Voltage drop across the inductor.
(c)
Impedance.
(d)
Resistance.
(e)
Inductance.
(f)
Draw a phasor diagram showing VR, VL, VT, and I (as reference) for the
circuit.
(g)
Draw an impedance triangle showing R, XL, Z and for the circuit.
11.
A series RL circuit is made from a 100 mH choke and a 1506 resistor. This circuit
is connected to a 20V function generator. Calculate VR and VL for each of the
following frequencies:
(a)
60 Hz.
(b)
200 Hz.
(c)
500 Hz.
(d)
1 kHz.
12.
Determine the magnitude and phase angle of the source voltage in the following
circuit.
ELTK1200
Marine Institute
Rev 2
118