Marlabs Interview Questions and Answers

The OLTC (On-Load Tap Changer) in a transformer is typically connected to the high voltage side.

• OLTC is connected to the high voltage winding of the transformer

• It allows for tap changing while the transformer is energized

• The low voltage side remains fixed while the high voltage side can be adjusted

Ten delta test is used to detect winding deformation and shorted turns in transformer.

• Detects winding deformation and shorted turns

• Helps in identifying internal faults

• Used for routine maintenance and troubleshooting

Bukolze relays are used in electrical engineering for their high reliability and ability to handle high voltage and current.

• Bukolze relays are known for their robustness and durability.

• They are commonly used in power distribution systems and industrial applications.

• These relays can handle high voltage and current levels, making them suitable for heavy-duty operations.

• They provide reliable switching and protection in electrical circuits.

• Bukolze relays are designed to withstand...read more

UV Coil provides protection against over voltage and under voltage.

• UV Coil is a device used in electrical systems to protect against voltage fluctuations.

• It monitors the voltage levels and activates when the voltage exceeds or falls below the specified limits.

• When the voltage exceeds the upper limit, the UV Coil disconnects the power supply to prevent damage to the equipment.

• Similarly, when the voltage falls below the lower limit, the UV Coil interrupts the power supply to av...read more

Explosion vent in transformer is used for safety purposes.

• It helps to release pressure build-up inside the transformer due to internal faults or external factors.

• It prevents the transformer from exploding and causing damage to the surrounding area.

• The vent is designed to open at a specific pressure level to ensure safe release of gases.

• It is a mandatory safety feature in transformers as per industry standards.

• Examples of external factors that can cause pressure build-up inclu...read more

Yes, OLTC is always connected in the HT voltage side.

• OLTC stands for On-Load Tap Changer.

• It is a device used in electrical power transformers to regulate the voltage level.

• OLTC is typically connected on the high voltage (HT) side of the transformer.

• It allows for tap changing while the transformer is energized and under load.

• By changing the tap position, the OLTC can adjust the transformer's output voltage.

• This helps to compensate for variations in the input voltage or load co...read more

Star delta is used in electrical engineering to reduce starting current and protect motors.

• Star delta connection is used for induction motors.

• It reduces the starting current by a factor of √3.

• It helps in reducing voltage drop during motor starting.

• It protects the motor from excessive current and overheating.

• It is commonly used in applications where the motor needs to start with a low current.

UV coil is a component used in HVAC systems to disinfect air by emitting ultraviolet light.

• UV coil is installed in the air handling unit of HVAC systems.

• It emits ultraviolet light to kill or deactivate microorganisms like bacteria, viruses, and mold spores.

• UV light damages the DNA and RNA of these microorganisms, preventing them from reproducing.

• UV coil helps improve indoor air quality by reducing the presence of harmful pathogens.

• Regular maintenance and cleaning of UV coil a...read more