Sigachi Industries Deputy Manager-Electrical Interview Questions and Answers

Star delta starter is a method used to reduce the starting current of induction motors.

• Star delta starter is used for starting induction motors in applications where the starting current needs to be limited.

• In star connection, the motor windings are connected in a star configuration during starting to reduce the voltage across each winding.

• After a certain time, the windings are switched to a delta configuration to run ...read more

Motor current formulas can be found using basic electrical principles and motor specifications.

• Use Ohm's Law (I = V / R) to calculate current based on voltage and resistance.

• For AC motors, use the formula I = P / (sqrt(3) * V * cos(theta)), where P is power, V is voltage, and theta is the power factor angle.

• Refer to motor datasheets for specific current ratings and calculations.

• Consider factors like efficiency, power f...read more

Protection in a transformer involves measures to prevent damage from overcurrent, overvoltage, and overheating.

• Use fuses or circuit breakers to protect against overcurrent

• Install surge arresters to protect against overvoltage

• Use temperature sensors and cooling systems to prevent overheating

• Implement differential protection to detect internal faults

• Regular maintenance and testing to ensure proper functioning

Faults in a transformer can include short circuits, open circuits, overheating, and insulation breakdown.

• Short circuits can occur due to insulation failure or winding damage.

• Open circuits can result from broken connections or faulty windings.

• Overheating may be caused by overloading or poor cooling.

• Insulation breakdown can lead to arcing and short circuits.