Electrical Engineering Interview Question and Answer

1). What is a three-phase electrical system?

An electrical system with three phases is a polyphase system that is mostly utilized for power generation and transmission. It is composed of three alternating currents with a phase difference of 1/3 of a cycle (120 degrees), all of which have the same frequency & voltage amplitude. This technology is more cost-effective and efficient when it comes to high power distribution.

2). Describe the power factor concept.

The efficiency with which electrical power is transformed into usable work output is measured by the power factor. It can be described as the ratio of perceived power (total power in the circuit) to real power (power used to perform work). More power factor is an indicator of effective power use.

3). Explain about the difference between a circuit breaker and a fuse.

The safety devices that stop overcurrent in electrical circuits are circuit breakers and fuses. A fuse is a single-use item that melts when too much current passes through it, cutting off the circuit. Conversely, a circuit breaker that trips as a result of an overcurrent can be reset.

4). How does an inverter operate and what does it do?

The electronic device known as an inverter is used to change direct current (DC) into alternating current (AC). It makes use of a switching circuit to quickly turn on and off the DC input, producing a square wave. After then, this wave is changed to a sine wave, which is better suited for use with other gadgets and home appliances.

5). How do transformers work?

Transformers are electrical devices that use electromagnetic induction to transmit electrical energy between two (or) more circuits. They operate on the basis of electromagnetic induction, or Faraday’s Law.

6). What are transformer types?

Step-up transformers, which increase voltage, and step-down transformers, which decrease voltage, are the two basic types of transformers.

7). What is the significance of a synchronous generator in power systems?

In order to generate power, an alternator, also known as a synchronous generator, is essential. It generates alternating current that is in sync with the frequency of the grid. It is an essential part of large-scale power plants and grid-connected systems because of its synchronous functioning, which guarantees consistent and well-coordinated power delivery.

8). Explain the electrical skin effect in further detail.

The tendency of alternating current (AC) to concentrate close to a conductor’s surface, especially at higher frequencies, is known as the “electrical skin effect.” This phenomenon affects the conductor’s current distribution by increasing effective resistance. When constructing high-frequency electrical systems, engineers have to take the skin effect into account.

9). How do semiconductors function in power electronics?

In power electronics, semiconductors are essential because they regulate the flow of electrical power. Inverters, converters, and motor drives are just a few of the devices that can efficiently convert, regulate, and manage electrical energy to components like power diodes, transistors, & thyristors. They support developments in electronic control systems and energy efficiency.

10). What is the importance of grounding in electrical systems?

Grounding is essential for electrical safety & system reliability. It allows fault currents to safely drain into the earth, avoiding electrical shocks & protecting equipment. Grounding maintains voltage levels, eliminates electromagnetic interference, and provides a reference point for precise voltage measurements in electrical systems.