Special Technical Services Interview Questions and Answers

Chillers are machines that remove heat from a liquid via a vapor-compression or absorption refrigeration cycle.

• Components include compressor, condenser, evaporator, expansion valve, and refrigerant.

• Types of chillers include air-cooled, water-cooled, and absorption chillers.

• Chillers are commonly used in HVAC systems for cooling large buildings or industrial processes.

Tests for transformers include turns ratio test, insulation resistance test, power factor test, and winding resistance test.

• Turns ratio test measures the turns ratio between primary and secondary windings.

• Insulation resistance test checks the insulation resistance of the transformer windings.

• Power factor test evaluates the power factor of the transformer.

• Winding resistance test measures the resistance of the transformer windings.

To check IR of XLPE cable, use a megger to measure insulation resistance.

• Use a megger to measure insulation resistance of XLPE cable

• Ensure the cable is de-energized before testing

• Compare the measured IR value with the manufacturer's specifications

• Repeat the test at different points along the cable for accuracy

A centrifugal compressor is a type of dynamic compressor that uses a rotating impeller to increase the pressure and flow of a gas.

• It works by converting kinetic energy into potential energy.

• It is commonly used in HVAC systems, gas turbines, and refrigeration systems.

• It is more efficient than positive displacement compressors for high flow rates and low pressure differentials.

• It can be single-stage or multi-stage, depending on the required pressure ratio.

• Examples include the I...read more

Types of excavations include trench excavation, basement excavation, road excavation, and pit excavation.

• Trench excavation involves digging a narrow channel in the ground for laying pipes or cables.

• Basement excavation is the process of digging out the foundation of a building to create a below-ground level.

• Road excavation is the removal of soil and rocks to construct or repair roads.

• Pit excavation involves digging a large hole in the ground for various purposes such as mining...read more

Risk assessment involves identifying hazards, evaluating risks, implementing control measures, and reviewing effectiveness.

• Identify hazards present in the workplace

• Evaluate the risks associated with each hazard

• Implement control measures to reduce or eliminate risks

• Review the effectiveness of the control measures

• Document the risk assessment process and findings