Pinnacle Infotech Interview Questions and Answers

MCB stands for Miniature Circuit Breaker. It is a type of electrical switch that automatically shuts off the electrical circuit during an overload or short circuit.

• Types of MCB include Single Pole MCB, Double Pole MCB, Triple Pole MCB, and Four Pole MCB.

• Other types of electrical instruments include Voltmeter, Ammeter, Multimeter, Oscilloscope, and Earth Tester.

• Types of electrical panels commonly used are Distribution Panels, Control Panels, and Motor Control Centers.

AC and DC are two types of electrical current. There are several types of switches used in electrical circuits.

• AC stands for Alternating Current and DC stands for Direct Current.

• AC current changes direction periodically while DC current flows in one direction only.

• Types of switches include toggle switches, rocker switches, push-button switches, and rotary switches.

• Switches can be classified based on their function, such as on/off switches, selector switches, and momentary swi...read more

A polyphase meter typically has three terminals.

• Polyphase meters are used to measure electrical energy in three-phase systems.

• These meters have three terminals, each corresponding to a phase (usually labeled as L1, L2, and L3).

• The three-phase system allows for more efficient power distribution and is commonly used in industrial and commercial settings.

• Examples of polyphase meters include electromechanical induction meters and electronic digital meters.

A transformer is a device that transfers electrical energy between two or more circuits through electromagnetic induction.

• Consists of two coils of wire, known as primary and secondary windings

• Works on the principle of electromagnetic induction

• Used to step up or step down voltage levels

• Commonly used in power distribution systems

• Examples include power transformers, distribution transformers, and instrument transformers

A motor is a device that converts electrical energy into mechanical energy to perform work.

• Motors are commonly used in various applications such as industrial machinery, household appliances, and vehicles.

• There are different types of motors including AC motors, DC motors, and servo motors.

• Motors consist of a rotor, stator, and various components such as windings, bearings, and brushes.

• The rotation of the motor is generated by the interaction between the magnetic fields produc...read more

VCB stands for Vacuum Circuit Breaker, which is a type of circuit breaker that uses vacuum as the arc quenching medium.

• VCB is used to interrupt the current flow in a circuit by creating a gap between contacts where the arc is extinguished in a vacuum.

• It is commonly used in medium voltage power systems for its high reliability and fast interruption speed.

• VCBs require less maintenance compared to other types of circuit breakers like oil or air circuit breakers.

• Example: Siemens ...read more

MCB working principle is to automatically switch off the electrical circuit during abnormal conditions like overload or short circuit.

• MCB detects abnormal conditions like overload or short circuit

• When abnormal condition is detected, MCB trips and disconnects the circuit

• MCB can be manually reset after tripping

• MCB provides protection to electrical circuits and appliances