SHYAM METALICS AND ENERGY Assistant Electrical Engineer Interview Questions, Process, and Tips

Fleming's Left Hand Rule and Right Hand Rule are used to determine the direction of force, current, or magnetic field in electromagnetism.

• Fleming's Left Hand Rule is used to determine the direction of force on a current-carrying conductor in a magnetic field.

• Fleming's Right Hand Rule is used to determine the direction of induced current in a conductor moving in a magnetic field.

• Both rules are based on the relationship ...read more

Motors convert electrical energy into mechanical energy, while generators convert mechanical energy into electrical energy.

• Motors work on the principle of electromagnetic induction, where a current-carrying conductor experiences a force in a magnetic field.

• Generators work on the principle of Faraday's law of electromagnetic induction, where a changing magnetic field induces an electromotive force in a conductor.

• Motors ...read more

A transformer works on the principle of electromagnetic induction to transfer electrical energy between two or more circuits.

• Transformers have two coils of wire, known as the primary and secondary coils, which are wound around a core made of ferromagnetic material.

• When an alternating current flows through the primary coil, it creates a changing magnetic field around the coil.

• This changing magnetic field induces a volta...read more

The control circuit of a star-delta starter involves two contactors and a timer for smooth transition from star to delta connection.

• The control circuit includes a main contactor for connecting the motor in star during starting.

• A timer is used to delay the transition from star to delta connection to prevent sudden voltage spikes.

• Once the timer elapses, a delta contactor is energized to switch the motor windings from sta...read more

Safety devices used in conveyor belts include pull cord switches, belt sway switches, and emergency stop switches.

• Pull cord switches are used to stop the conveyor belt in case of emergency by pulling the cord.

• Belt sway switches are used to detect any misalignment or deviation of the belt and trigger an alarm or stop the conveyor.

• Emergency stop switches are placed at regular intervals along the conveyor belt to quickly

Electrical preventive maintenance activities include inspection, testing, cleaning, and replacement of components to prevent breakdowns.

• Regular inspection of electrical systems

• Testing of equipment for proper functioning

• Cleaning of electrical components to prevent dust buildup

• Replacement of worn out or damaged parts

• Tightening of connections to prevent loose connections

• Checking for overheating issues

• Updating software/fir...read more

The generator excitation system is a system that provides the necessary field current to the generator rotor to produce the desired voltage output.

• The excitation system controls the magnetic field strength of the generator to regulate the output voltage.

• It typically consists of an exciter, voltage regulator, and automatic voltage regulator (AVR).

• The exciter produces the field current, the voltage regulator adjusts the ...read more

Common malfunctions and troubleshooting methods for electrical feeders

• Common malfunctions include short circuits, overloads, and open circuits

• Troubleshooting methods involve checking for loose connections, using a multimeter to test for continuity, and inspecting for physical damage

• In case of a short circuit, isolate the fault by disconnecting sections of the feeder until the fault is located

• For overloads, check the lo...read more

The minimum megger value required for high tension (HT) and low tension (LT) motors is typically 500V for HT motors and 250V for LT motors.

• Minimum megger value for HT motors is usually 500V

• Minimum megger value for LT motors is typically 250V

• Megger testing is essential to ensure insulation resistance in motors

A Megger generates DC voltage to test insulation resistance in electrical systems.

• A Megger generates DC voltage typically ranging from 250V to 5000V

• The reason for using DC voltage is to accurately measure the insulation resistance of electrical systems

• DC voltage helps in detecting any insulation faults or breakdowns in the system

• The high voltage generated by a Megger helps in identifying potential issues before they ca

The Megger value of unsatisfactory insulation can be improved by drying out the insulation, repairing any damaged areas, and retesting.

• Dry out the insulation using heaters or fans to remove moisture

• Repair any damaged areas by replacing or patching up the insulation

• Retest the insulation using the Megger to ensure the value has improved

• Consider using insulation coatings or sealants to improve the insulation resistance

Maintenance practices for transformers include regular inspections, testing, cleaning, and oil analysis.

• Regularly inspecting for signs of overheating, leaks, or damage

• Performing routine testing such as insulation resistance and turns ratio tests

• Keeping the transformer and surrounding area clean and free of debris

• Conducting oil analysis to monitor the condition of the transformer oil

• Ensuring proper ventilation and cooli...read more

Steps to be taken if a transformer trips due to Buchholz relay acting

• Immediately isolate the transformer from the system to prevent further damage

• Inspect the transformer and Buchholz relay for any faults or leaks

• Reset the Buchholz relay and check for proper functioning

• Investigate the cause of the trip such as internal faults or oil contamination

• Repair or replace any faulty components before re-energizing the transforme

Protective measures for a transformer include overcurrent protection, temperature monitoring, and regular maintenance.

• Overcurrent protection: Use fuses or circuit breakers to protect against excessive current flow.

• Temperature monitoring: Install temperature sensors to prevent overheating.

• Regular maintenance: Inspect and test the transformer regularly to ensure proper functioning.

• Grounding: Properly ground the transform...read more

Bus changeover scheme is a system used to transfer power supply from one source to another in case of a fault or maintenance.

• Bus changeover scheme involves the use of automatic transfer switches (ATS) or manual switches to transfer power sources.

• It ensures uninterrupted power supply by quickly switching to an alternate power source when needed.

• Common examples include dual power supply systems in data centers or hospita...read more