Cosmo Auto Tech Interview Questions and Answers

Transformers breathe through cooling systems and use materials like oil or air for insulation.

• Transformers have cooling systems to dissipate heat generated during operation.

• The cooling system can be either oil-based or air-based.

• Oil-filled transformers use oil as a cooling and insulating medium.

• Air-cooled transformers use fans or radiators to cool the windings.

• The cooling system ensures the transformer operates within safe temperature limits.

Machines ratings are in kVA instead of kW due to the presence of reactive power.

• kVA represents the apparent power of a machine, which includes both real power (kW) and reactive power (kVAR).

• Reactive power is required by machines with inductive or capacitive loads to create magnetic fields or store energy.

• kW represents the actual power consumed or produced by a machine, while kVA represents the total power required to perform work.

• Using kVA ratings helps in sizing electrical e...read more

Parameters for synchronisation of DG set to bus bar

• Frequency matching between DG set and bus bar

• Voltage matching between DG set and bus bar

• Phase sequence matching between DG set and bus bar

• Synchronisation panel settings

• Proper earthing and grounding

• Load sharing and load transfer

• Protection and safety measures

Single phase machines are designed by using a single phase power supply and incorporating specific design elements.

• Single phase machines use a single phase power supply, typically from a residential or commercial electrical system.

• They are designed with specific components such as a single phase winding, a capacitor for starting, and a centrifugal switch for switching between starting and running modes.

• Examples of single phase machines include single phase induction motors, s...read more

HG fuse is a high-grade fuse used in electrical systems to protect against overcurrents.

• HG fuse stands for High-Grade fuse.

• It is used in electrical systems to protect against overcurrents.

• It works by melting a fuse element when excessive current flows through it.

• The melting of the fuse element breaks the circuit and prevents damage to the electrical system.

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

CT/PT are used in electrical systems to measure and protect against high currents and voltages.

• CT (Current Transformer) is used to measure high currents and step them down to a manageable level for measurement or protection devices.

• PT (Potential Transformer) is used to measure high voltages and step them down to a safe level for measurement or protection devices.

• CTs and PTs are commonly used in power systems, electrical substations, and industrial applications.

• CTs and PTs pro...read more