Alstom Transportation Electrical Engineer Interview Questions and Answers

Synchronous motors operate at a constant speed determined by the frequency of the power source.

• Synchronous motors have a rotor that rotates at the same speed as the rotating magnetic field in the stator.

• They are used in applications where constant speed is required, such as in industrial processes or power generation.

• Synchronous motors are more efficient than induction motors at higher loads.

• They require a separate DC ...read more

Induction motors rely on induction to produce torque, while synchronous motors require a magnetic field to rotate at a constant speed.

• Induction motors do not require any external connections to the rotor, while synchronous motors need a DC power source to create the magnetic field.

• Induction motors are self-starting, while synchronous motors require external means to start.

• Induction motors are more commonly used in indu...read more

DOL starter stands for Direct-On-Line starter, used to start motors by directly connecting them to the power supply.

• DOL starter is the simplest and most common type of motor starter.

• It directly connects the motor to the power supply without any intermediate starting method.

• It provides full voltage to the motor during starting, which can cause high inrush current.

• DOL starters are suitable for small to medium-sized motor...read more

APFC PANEL stands for Automatic Power Factor Correction Panel, used to maintain power factor in electrical systems.

• APFC PANEL automatically monitors and corrects the power factor of electrical systems.

• It helps in reducing electricity bills by maintaining a high power factor.

• APFC PANELs are commonly used in industries and commercial buildings.

• They consist of capacitors that are switched on and off based on the load requ...read more

ATS stands for Automatic Transfer Switch. It is used to transfer power supply between two sources. Transformer and motor maintenance procedures and protection methods are essential for their efficient operation. SAP is a software used for enterprise resource planning.

• ATS is used to automatically switch power supply between two sources, ensuring uninterrupted power supply.

• Transformer maintenance involves regular inspect...read more

HT motor rating is the maximum power it can handle and FLC is the current it draws at full load.

• HT motor rating is expressed in kilowatts (kW) or megawatts (MW).

• FLC of HT motor is the full load current it draws at rated voltage and frequency.

• FLC is expressed in amperes (A) and varies depending on the motor's power rating and efficiency.

• For example, a 1 MW HT motor may have a FLC of 1000 A at 11 kV.

• The rating and FLC of...read more

Plant EHT system and single line diagram of plants.

• EHT system refers to Extra High Tension system used in power plants

• Single line diagram shows the electrical connections between different components

• It is important to have a clear and accurate diagram for safety and maintenance purposes

The major parts in a power transformer include the core, windings, insulation, cooling system, and tap changer.

• Core: Provides a path for magnetic flux and is usually made of laminated steel sheets.

• Windings: Consist of primary and secondary coils that transfer electrical energy.

• Insulation: Prevents electrical leakage and ensures safety.

• Cooling System: Keeps the transformer within operating temperature limits, commonly u...read more

I want to switch electrical circuits and devices.

• Switching electrical circuits to control the flow of electricity.

• Switching electrical devices on or off.

• Switching between different power sources.

• Switching between different modes or settings of electrical equipment.

• Switching between different electrical connections or configurations.