The Social Brew Interview Questions and Answers

Lightning impulse test of a power transformer is a high voltage test to simulate lightning strikes and ensure the transformer can withstand sudden voltage surges.

• It is a high voltage test conducted to simulate lightning strikes on the transformer

• The test is performed to ensure the transformer can withstand sudden voltage surges

• It helps in evaluating the insulation strength and overall performance of the transformer

• The test involves applying a high voltage impulse to the trans...read more

650kVp is chosen for lighting impulse level for 132kV due to its ability to withstand lightning strikes and protect the equipment.

• 650kVp is a standard value chosen based on the insulation level required for 132kV systems

• Lightning impulse level is selected to ensure equipment can withstand lightning strikes without damage

• Higher impulse levels provide better protection against lightning-induced surges

• Choosing the right impulse level is crucial for ensuring the reliability and s...read more

Voltage rating in multiples of 11 is common due to historical reasons and practical considerations.

• Historically, early power systems used 110V and 220V as standard voltages.

• Multiples of 11 make it easier to design transformers and other electrical equipment.

• Standardizing on multiples of 11 simplifies the distribution and transmission of power.

• Common voltage ratings like 110V, 220V, 440V, etc., are all multiples of 11.

Speed control of an AC machine is achieved by varying the frequency of the input power supply.

• Speed control is typically done using a variable frequency drive (VFD) which adjusts the frequency of the input power to the motor.

• By increasing or decreasing the frequency, the motor speed can be controlled without changing the number of poles in the motor.

• For example, in an industrial setting, a VFD may be used to control the speed of a conveyor belt or a pump motor.

• Speed control i...read more

Heat run test of transformer is a test conducted to assess the performance of a transformer under normal operating conditions.

• Heat run test involves running the transformer at full load for a specified period of time to evaluate its temperature rise.

• The test helps in determining if the transformer can handle the heat generated during normal operation without overheating.

• It is essential to ensure that the transformer can operate efficiently and safely under varying load condit...read more

An induction machine is an AC electric motor in which the electric current in the rotor needed to produce torque is induced by electromagnetic induction from the magnetic field of the stator winding.

• Induction machines are commonly used in various industrial applications for their simplicity, reliability, and low maintenance requirements.

• They operate on the principle of electromagnetic induction, where a rotating magnetic field in the stator induces current in the rotor, causi...read more