Vestas Service Technician Interview Questions and Answers

A line diagram of a wind turbine generator (WTG) shows the flow of energy from wind to electricity.

• The diagram typically includes the rotor blades, gearbox, generator, and power electronics

• The blades capture wind energy and turn the rotor, which drives the gearbox

• The gearbox increases the rotational speed and sends it to the generator

• The generator converts the rotational energy into electrical energy

• The power electroni...read more

DFIG converters are used in wind turbines to convert variable frequency AC power to DC power and back to AC power.

• DFIG stands for Doubly Fed Induction Generator

• The converter consists of two back-to-back voltage source converters

• One converter controls the rotor current and the other controls the grid current

• The rotor current is controlled to maintain a constant torque on the turbine

• The grid current is controlled to main...read more

Earth is the connection between an electrical circuit and the ground, while neutral is the return path for current in a circuit.

• Earth is a safety measure to prevent electric shock and protect against electrical faults.

• Neutral carries the current back to the source in a circuit.

• Earth is typically connected to the ground through a grounding electrode.

• Neutral is usually connected to the center tap of a transformer.

• In a th...read more

Plant load factor is a measure of the actual output of a power plant compared to its maximum possible output.

• Plant load factor is calculated by dividing the actual energy generated by the plant over a specific period by the maximum possible energy that could have been generated during the same period.

• It is expressed as a percentage and indicates how efficiently a power plant is being utilized.

• A high plant load factor i...read more

Machine availability is the percentage of time a machine is able to be used for its intended purpose.

• Machine availability is calculated by dividing the total operating time by the total time in a given period, then multiplying by 100.

• For example, if a machine operates for 800 hours in a month and there are 1000 total possible operating hours, the availability would be 80%.

• Factors like downtime, maintenance, and repairs

Performing 5 seconds maintenance tasks on a daily basis at work.

• Performing regular maintenance tasks can help prevent equipment breakdowns and prolong their lifespan.

• Examples of 5-second maintenance tasks include wiping down equipment, checking for loose screws, and clearing debris.

• By incorporating these tasks into a daily routine, employees can ensure that equipment is functioning properly and avoid costly repairs.

• Reg...read more

The raw material for wind blade manufacturing is primarily fiberglass and resin.

• Fiberglass is a composite material made of glass fibers and resin.

• The resin is typically a thermosetting polymer that hardens when cured.

• Other materials such as carbon fiber, balsa wood, and foam may also be used in the manufacturing process.

• The raw materials are layered and molded into the desired shape of the wind blade.

• The manufacturing ...read more

IGBT stands for Insulated Gate Bipolar Transistor, a semiconductor device used for switching applications in power electronics.

• IGBT is a type of transistor that combines the high efficiency of a bipolar junction transistor (BJT) with the high input impedance of a MOSFET.

• It is commonly used in applications such as motor drives, inverters, and power supplies.

• IGBTs are used for high power applications due to their ability...read more