BHEL Interview Questions and Answers

AC and DC are two types of electrical currents with different characteristics.

• AC stands for alternating current, which periodically changes direction.

• DC stands for direct current, which flows in one direction.

• AC is commonly used in household appliances and power distribution systems.

• DC is commonly used in batteries and electronic devices.

• AC can be easily converted to different voltages using transformers.

• DC is more sta...read more

There are mainly three types of solar energy systems: solar photovoltaic (PV), solar thermal, and concentrated solar power (CSP).

• Solar photovoltaic (PV) systems convert sunlight directly into electricity using solar panels.

• Solar thermal systems use sunlight to heat water or air for use in buildings or to generate electricity.

• Concentrated solar power (CSP) systems use mirrors or lenses to concentrate sunlight onto a sma...read more

Insulators are used in electrical systems to prevent the flow of electricity. They can be found in various locations.

• Insulators are commonly found on electrical poles to support power lines.

• Insulators are also used in electrical devices to prevent electrical current from flowing where it shouldn't.

• Insulators can be made of materials such as glass, porcelain, or plastic.

• Insulators are crucial in maintaining the safety a...read more

Isolators are devices used to separate a specific area or process from its surroundings to prevent contamination or exposure.

• Glove box isolator

• Containment isolator

• Pharmaceutical isolator

• Biological safety cabinet

Transformers are electrical devices that transfer electrical energy between two or more circuits through electromagnetic induction.

• Transformers consist of primary and secondary coils wound around a core

• They can step up or step down voltage levels

• Common examples include power transformers used in electrical substations

There are various types of transformers including power transformers, distribution transformers, instrument transformers, etc.

• Power transformers are used in power generation and transmission

• Distribution transformers are used to supply power to homes and businesses

• Instrument transformers are used for measuring voltage and current levels

• Auto transformers are used for voltage regulation

• Isolation transformers are used to i...read more

Loss transformers are transformers that experience a decrease in efficiency or performance due to various factors.

• Loss transformers can be caused by factors such as overheating, overloading, poor maintenance, or insulation breakdown.

• Loss transformers can result in decreased energy efficiency, increased energy consumption, and potential equipment damage.

• Examples of loss transformers include those found in power distribu...read more

Transformers are classified based on their construction, cooling method, and purpose.

• Transformers can be classified as core type or shell type based on their construction.

• They can also be classified as dry type or oil-filled based on their cooling method.

• Transformers can be power transformers, distribution transformers, instrument transformers, etc. based on their purpose.

Inverters are electronic devices that convert direct current (DC) to alternating current (AC) for use in electrical systems.

• Inverters are commonly used in solar power systems to convert DC electricity generated by solar panels into usable AC electricity.

• They are also used in backup power systems to convert DC power from batteries into AC power during power outages.

• Inverters come in various sizes and types, including gr...read more

Rectifiers are electronic devices used to convert alternating current (AC) to direct current (DC) by allowing current to flow in only one direction.

• Rectifiers are classified into two main types: half-wave rectifiers and full-wave rectifiers.

• Half-wave rectifiers allow current to flow in one direction during one half of the AC cycle, while full-wave rectifiers allow current to flow in one direction during both halves of ...read more

Conductors are typically found in electrical systems and are used to carry electrical current.

• Conductors are commonly found in electrical wires and cables.

• They are used to transmit electricity from a power source to a device or appliance.

• Examples of conductors include copper wires, aluminum wires, and metal bars.

• Conductors have low resistance to electrical current flow.

A magnetic circuit is a closed path followed by magnetic flux.

• Consists of a magnetic material that conducts magnetic flux

• Includes a source of magnetic field (e.g. magnet)

• May have air gaps or non-magnetic materials that affect the flow of magnetic flux

Heat is energy transfer due to temperature difference; temperature measures particle energy.

• Heat is energy in transit, while temperature is a measure of energy within a substance.

• Heat flows from hot to cold; for example, a hot cup of coffee cools down in a cooler room.

• Temperature is measured using scales like Celsius or Fahrenheit; for instance, water freezes at 0°C.

• Heat can change the state of matter, like melting ice...read more