Vishnu Chemicals Junior Engineer Electrical Interview Questions and Answers

Vector group of transformers is used to determine the phase difference and voltage ratio between primary and secondary windings.

• Vector group helps in determining the correct connection of transformers in parallel.

• It helps in identifying the phase angle difference between primary and secondary windings.

• It helps in determining the voltage ratio between primary and secondary windings.

• Vector group is important for power sy...read more

IR value is a measure of insulation resistance in transformers and motors.

• IR value indicates the condition of insulation in transformers and motors.

• It is measured in megaohms (MΩ) using a megger.

• A high IR value indicates good insulation while a low value indicates poor insulation.

• Regular testing of IR value is important to prevent breakdowns and ensure safety.

• For example, a transformer with an IR value of less than 1 M...read more

Switchgear selection for a 75 kW motor depends on various factors such as voltage, current, starting method, and protection requirements.

• Consider the voltage and current rating of the motor

• Choose the appropriate starting method such as DOL, star-delta, soft starter, or VFD

• Select the switchgear with suitable protection features such as overload, short circuit, and earth fault protection

• Ensure compatibility with the exis...read more

Designing a 100 KVR capacitor for 415 volts.

• Calculate the required capacitance using the formula C = I / (2 * pi * f * V)

• Select a suitable type of capacitor based on the application and voltage rating

• Ensure proper installation and maintenance to prevent failure or damage

• Consider safety precautions when working with high voltage capacitors