10+ eNoah iSolution Interview Questions and Answers

OC test is done on LV side to avoid high voltage on secondary side. SC test is done on HV side to avoid high current on primary side.

• LV side has lower voltage rating, hence safer for OC test

• HV side has higher current rating, hence suitable for SC test

• OC test checks insulation resistance and winding resistance

• SC test checks impedance and voltage regulation

• Example: A 100 MVA transformer with 220 kV HV and 33 kV LV rating

Tests done on a transformer include insulation resistance test, turns ratio test, winding resistance test, and load test.

• Insulation resistance test checks the insulation resistance between windings and between windings and ground.

• Turns ratio test measures the ratio of the number of turns in the primary winding to the number of turns in the secondary winding.

• Winding resistance test measures the resistance of each winding to ensure it is within acceptable limits.

• Load test evalu...read more

High voltage is used for transmission to reduce power loss and increase efficiency.

• High voltage reduces the current required for a given amount of power, which reduces power loss due to resistance in the transmission lines.

• Lower current also means smaller conductors can be used, reducing material and installation costs.

• High voltage transmission is more efficient over long distances, reducing the need for additional power generation.

• Examples of high voltage transmission system...read more

The generation voltage in India varies depending on the location and power plant.

• The voltage ranges from 110V to 440V depending on the location.

• The power plants generate electricity at different voltages.

• The national grid operates at a voltage of 400kV and 765kV.

• India has a mix of AC and DC power transmission systems.

CT and PT are used in electrical systems for measurement and protection purposes.

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

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

• CTs and PTs provide isolation and safety by separating the high voltage/current circuits from the low voltage/current circuits....read more

Renewable energy power plants are generally cheaper to install than traditional fossil fuel power plants.

• Renewable energy power plants such as solar, wind, and hydroelectric are cheaper to install than traditional fossil fuel power plants.

• The cost of installation for renewable energy power plants has decreased significantly in recent years due to advancements in technology and increased demand.

• Fossil fuel power plants require expensive infrastructure and equipment, such as pi...read more

Power transformers are used to step up or step down voltage for transmission and distribution transformers are used to distribute power to end-users.

• Power transformers are typically used in power generation plants and substations.

• Distribution transformers are used to supply power to residential, commercial, and industrial areas.

• Power transformers have higher voltage ratings and are designed for long-distance transmission.

• Distribution transformers have lower voltage ratings an...read more

The required materials for designing a transformer include a magnetic core, copper wire, insulation materials, and cooling systems.

• Magnetic core: Typically made of laminated iron or steel to provide a low reluctance path for the magnetic flux.

• Copper wire: Used for winding the primary and secondary coils to carry the electrical current.

• Insulation materials: Used to insulate the copper wire and prevent short circuits.

• Cooling systems: Required to dissipate heat generated during ...read more

MCCB stands for Molded Case Circuit Breaker and is a type of circuit breaker used for electrical protection. A directional valve is a type of valve used to control the direction of fluid flow in a hydraulic system.

• MCCB is a type of circuit breaker that provides protection against overcurrents in electrical systems.

• It is commonly used in industrial and commercial applications.

• MCCBs are designed to trip and interrupt the circuit when excessive current flows through it.

• They are ...read more

1st angle projection is commonly used in Europe and Asia, while 3rd angle projection is commonly used in North America.

• 1st angle projection: object is placed in the first quadrant, with the plane of projection between the object and observer.

• 3rd angle projection: object is placed in the third quadrant, with the plane of projection behind the object.

• 1st angle projection is more intuitive for designers, while 3rd angle projection is easier for machinists to interpret.

• Example: I...read more