200+ Diploma Electrical Engineer Interview Questions and Answers

Star delta connection is used to start high power motors with reduced starting current and torque.

• Reduces starting current and torque

• Used for high power motors

• Improves motor efficiency

• Reduces voltage drop during starting

• Reduces stress on motor windings

• Example: Starting a large induction motor in an industrial setting

Different types of cables are used for power transmission, including overhead lines, underground cables, and submarine cables.

• Overhead lines are commonly used for power transmission over long distances.

• Underground cables are used in urban areas where overhead lines are not feasible.

• Submarine cables are used for power transmission between islands or across bodies of water.

• Different types of cables, such as aluminum cables and copper cables, are used based on the specific requi...read more

There are three types of motors in electrical systems: synchronous, asynchronous (induction), and special motors.

• Asynchronous motors include squirrel cage and slip ring induction motors.

• Special motors include universal, stepper, brushless DC, and servo VFD motors.

• Synchronous motors are used in applications where constant speed is required, while asynchronous motors are used in most industrial applications.

• Special motors have unique features such as high torque, precise contro...read more

Generators and alternators are both electrical machines that convert mechanical energy into electrical energy, but they differ in their construction and working principles.

• Generators produce direct current (DC) while alternators produce alternating current (AC).

• Generators use a commutator and brushes to convert mechanical energy into electrical energy, while alternators use slip rings and brushes.

• Generators are typically used in small-scale applications, such as portable powe...read more

Yes, there are different types of wires used in transmission.

• The most common types of wires used in transmission are copper, aluminum, and steel-cored aluminum.

• Copper wires are the most efficient and expensive, while aluminum wires are less efficient but more affordable.

• Steel-cored aluminum wires are used for long-distance transmission as they have high tensile strength.

• Other types of wires used in transmission include ACSR (Aluminum Conductor Steel Reinforced) and AAC (All A...read more

Another name for induction motor is asynchronous motor.

• Asynchronous motor is commonly used in industrial applications.

• It operates at a slightly slower speed than the synchronous speed.

• Examples include squirrel cage induction motor and wound rotor induction motor.

The neutral wire carries current back to the source, while the earth wire provides a path for electrical faults to safely discharge.

• Neutral wire carries current back to the source

• Earth wire provides a path for electrical faults to safely discharge

• Neutral wire is typically colored white or gray

• Earth wire is typically colored green or green with yellow stripes

• Neutral wire is connected to the grounding system at the main electrical panel

• Earth wire is connected to the grounding e...read more

The acceptable current for humans depends on various factors such as duration, frequency, and pathway.

• The acceptable current for humans is typically below 1 mA for low-frequency currents.

• For high-frequency currents, the acceptable current is lower, usually below 0.1 mA.

• The duration of exposure also plays a significant role in determining the acceptable current.

• The pathway of the current through the body, such as hand-to-hand or hand-to-foot, affects the acceptable current.

• Fac...read more

Substations are used in distribution and transmission lines to control voltage levels, protect equipment, and facilitate power transfer.

• Substations help in stepping up or stepping down the voltage levels as required.

• They provide a centralized location for monitoring and controlling the flow of electricity.

• Substations house transformers, circuit breakers, and other equipment for voltage regulation and protection.

• They enable power transfer between different transmission lines o...read more

An electrical machine is a device that converts electrical energy into mechanical energy or vice versa. Ohm's Law relates voltage, current, and resistance. KVL and KCL are laws used in circuit analysis.

• Electrical machine is a device that converts electrical energy into mechanical energy or vice versa

• Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conduct...read more

Induction motors run at high speed at no load conditions

• Induction motors

• Asynchronous motors

• Squirrel cage motors

Different types of electric vehicle batteries include lithium-ion, lead-acid, and nickel-metal hydride, each impacting performance in terms of energy density, weight, cost, and charging time.

• Lithium-ion batteries are commonly used in electric vehicles due to their high energy density, lightweight, and long lifespan.

• Lead-acid batteries are less expensive but heavier and have lower energy density compared to lithium-ion batteries.

• Nickel-metal hydride batteries are a middle-grou...read more

Transformers cannot operate on DC supply due to the absence of changing magnetic field required for induction.

• Transformers work on the principle of electromagnetic induction, which requires a changing magnetic field.

• DC supply produces a constant magnetic field, which does not induce a voltage in the secondary coil of the transformer.

• AC supply, on the other hand, produces a changing magnetic field, allowing for induction and voltage transformation.

• Operating a transformer on DC...read more

A clamp meter is a tool used to measure electrical current without the need to disconnect the circuit, while a teco meter is used to measure the speed of an electric motor. Capacitance is the ability of a component to store electrical charge.

• Clamp meter is used to measure electrical current in a conductor without the need for direct contact.

• Teco meter is used to measure the speed of an electric motor.

• Capacitance is the ability of a component to store electrical charge, measur...read more

I have 2 years of experience working with PLCs, SCADA systems, and industrial robots in the automation field.

• Experience with programming PLCs for automated control systems

• Knowledge of SCADA systems for monitoring and controlling industrial processes

• Hands-on experience with industrial robots for automation tasks

• Familiarity with sensors, actuators, and other automation components

• Worked on projects involving automation in manufacturing and production environments

VCB stands for Vacuum Circuit Breaker. It is a type of electrical switchgear used for protecting electrical circuits from overloads and short circuits.

• VCB uses vacuum as the arc quenching medium instead of oil or air.

• It is installed in high voltage power systems, such as substations and power plants.

• VCBs are commonly used in distribution networks, generator circuits, and transformer circuits.

• They provide reliable and efficient protection against electrical faults.

• Examples of ...read more

There are mainly two types of solar panel installation: On-grid and Off-grid.

• On-grid installation is connected to the main power grid and excess energy can be sold back to the utility company.

• Off-grid installation is not connected to the main power grid and requires battery storage to store excess energy.

• Other types include ground-mounted, roof-mounted, and pole-mounted installations.

• Installation methods can also vary depending on the type of roof or ground surface.

Siemens is an electrical manufacturing company that produces a wide range of electrical products and solutions for various industries.

• Siemens is a global company that produces electrical products and solutions for industries such as energy, healthcare, and transportation.

• Their products include power generation equipment, automation systems, medical imaging equipment, and more.

• Siemens is known for their innovative technologies and commitment to sustainability.

• In the electrical...read more

There are several types of transformers used in electrical engineering.

• Power transformers

• Distribution transformers

• Instrument transformers

• Auto transformers

• Isolation transformers

• Step-up transformers

• Step-down transformers

Primary connection sequence: H1-H2, Secondary connection sequence: X1-X2

• Primary connection sequence is typically H1-H2

• Secondary connection sequence is typically X1-X2

• The primary winding is connected to the supply voltage, while the secondary winding is connected to the load

• The connection sequence may vary depending on the transformer manufacturer and design

• Proper connection sequence is crucial for the transformer to function correctly

Motors and generators are electrical machines that convert electrical energy into mechanical energy and vice versa. PCB and soldering are components used in electronic circuits.

• Motors convert electrical energy into mechanical energy to produce motion.

• Generators convert mechanical energy into electrical energy.

• PCB (Printed Circuit Board) is a board made of insulating material with conductive pathways etched onto it to connect electronic components.

• Soldering is the process of j...read more

AC and DC are two types of electrical current. There are two types of transformers - step-up and step-down.

• AC stands for alternating current and DC stands for direct current

• AC changes direction periodically while DC flows in one direction

• Step-up transformers increase voltage while step-down transformers decrease voltage

• Transformers are used to transfer electrical energy from one circuit to another

• Examples of AC devices include household appliances and power grids, while examp...read more

Transformers, motors, and molding machines are essential electrical devices used in various industrial applications.

• Transformer: A device that transfers electrical energy between two or more circuits through electromagnetic induction, used in power distribution.

• Example: Step-up transformers increase voltage for long-distance transmission, while step-down transformers reduce voltage for local use.

• Motor: An electromechanical device that converts electrical energy into mechanica...read more

The question is asking for knowledge about all types of electrical systems.

• Knowledge of different types of electrical systems such as AC, DC, single-phase, three-phase, etc.

• Understanding of electrical components and their functions, such as resistors, capacitors, transformers, etc.

• Familiarity with electrical codes and regulations.

• Ability to read and interpret electrical schematics and diagrams.

• Troubleshooting skills to identify and fix electrical faults.

• Knowledge of electrica...read more

Stationary armature and rotating field system offers advantages like simplified construction, reduced maintenance, and improved efficiency.

• Simplified construction: Stationary armature allows for a simpler design with fewer moving parts, reducing the chances of mechanical failure.

• Reduced maintenance: With the armature stationary, there is less wear and tear on the components, leading to lower maintenance requirements.

• Improved efficiency: The rotating field system allows for be...read more

There are no specific types of beakers used in electrical engineering.

• There are no beakers specifically used in electrical engineering.

• Beakers are commonly used in chemistry labs for measuring and mixing liquids.

• In electrical engineering, other types of equipment like multimeters, oscilloscopes, and power supplies are used.

A work slot conveyor is a type of conveyor system used to transport workpieces between different workstations in a manufacturing facility.

• Work slot conveyors typically consist of a series of slots or compartments that hold the workpieces securely in place during transportation.

• The conveyor moves the workpieces along a predetermined path, stopping at each workstation where a specific task is performed.

• Work slot conveyors are commonly used in assembly lines for industries such ...read more