Basic Electrical Engineering Exam

The open circuit test determines the core losses while the short circuit test evaluates the copper losses in the transformer.

The short circuit test is performed on the high voltage side to minimize the current and simplify the test conditions.

The total power is 10.5 kW + (-2.5 kW) = 8.0 kW.

<p>Equal wattmeter readings indicate a balanced load in the system, where each phase carries the same current.</p> Signup and view all the answers

<p>A zero reading on one wattmeter indicates that the load is unbalanced, as one phase carries no power.</p> Signup and view all the answers

<p>A 1-phase induction motor lacks a rotating magnetic field, which prevents it from starting on its own.</p> Signup and view all the answers

<p>One method of speed control for a DC shunt motor is by varying the armature voltage using a rheostat.</p> Signup and view all the answers

<p>The main types of torques required are deflection torque, controlling torque, and damping torque.</p> Signup and view all the answers

<p>The monthly bill amounts to Rs. 207.00 based on the given loads.</p> Signup and view all the answers

<p>MCBs provide overload and short-circuit protection, while MCCBs offer adjustable settings and higher current ratings, making them safer than SFUs.</p> Signup and view all the answers

<p>Active power is the real power consumed by electrical devices to perform work, measured in watts (W), whereas reactive power is used to maintain the electric and magnetic fields in inductive and capacitive components, measured in volt-amperes reactive (VAR).</p> Signup and view all the answers

<p>The rms value of a signal is the square root of the average of the squares of the instantaneous values, representing effective power, while the average value is simply the arithmetic mean of the signal's values over a complete cycle.</p> Signup and view all the answers

<p>Power factor indicates the ratio of active power to apparent power in an AC system, influencing the efficiency of power delivery; a power factor closer to 1 means more efficient use of electrical power.</p> Signup and view all the answers

<p>Earthing is the process of connecting the non-live parts of an electrical system to the ground to prevent electric shock hazards and ensure safety by providing a low-resistance path for fault currents.</p> Signup and view all the answers

<p>Batteries have characteristics like capacity (measured in Ah), voltage, energy density, cycle life, and discharge rates that determine their performance in energy storage and delivery.</p> Signup and view all the answers

<p>Magnetic materials can be classified into ferromagnetic, paramagnetic, diamagnetic, and antiferromagnetic based on their magnetic properties and response to external magnetic fields.</p> Signup and view all the answers

<p>Series resonance occurs in an RLC circuit when the inductive and capacitive reactances are equal, minimizing impedance, and is expressed as $f_r = \frac{1}{2\pi\sqrt{LC}}$, where $L$ is inductance and $C$ is capacitance.</p> Signup and view all the answers

<p>Nodal analysis involves setting up equations based on Kirchhoff's current law at each node, allowing calculation of unknown currents by analyzing voltage differences across resistors.</p> Signup and view all the answers

<p>You can use the formula $I = V \times (\frac{1}{R} + j\omega C)$, where you can first find the current through the resistor and then determine the capacitive current to solve for the capacitance.</p> Signup and view all the answers

<p>Transformer losses include copper losses (due to resistance in windings), core losses (hysteresis and eddy current losses), and stray losses; maximum efficiency occurs when the variable copper losses equal the constant core losses.</p> Signup and view all the answers