Descon HSE Supervisor Interview Questions and Answers

Power factor is a measure of how effectively electrical power is being used in a system.

• Power factor is the ratio of real power (kW) to apparent power (kVA) in an electrical system.

• It indicates how efficiently power is being converted into useful work.

• A power factor of 1 indicates all power is being used effectively, while a lower power factor means some power is being wasted.

• Power factor correction can be used to impr

Dyn 11 is a transformer connection where the primary winding is connected in delta and the secondary winding is connected in star with neutral grounded.

• Dyn 11 is a common transformer connection used in power distribution systems.

• In Dyn 11 connection, the primary winding is connected in delta configuration while the secondary winding is connected in star configuration with neutral grounded.

• This configuration provides a ...read more

IDMT relay stands for Inverse Definite Minimum Time relay, used for protection in electrical systems.

• IDMT relay is a type of protective relay used in electrical systems.

• It operates based on the principle of inverse time characteristics.

• The relay operates faster for higher fault currents and slower for lower fault currents.

• IDMT relays are commonly used for overcurrent protection in power systems.

• They are designed to tri...read more

There are two main types of cooling in transformers: oil cooling and air cooling.

• Oil cooling involves circulating oil within the transformer to dissipate heat.

• Air cooling uses fans to blow air over the transformer coils to cool them down.

• Oil cooling is more efficient but requires more maintenance, while air cooling is simpler and cheaper.

• Examples of oil-cooled transformers include distribution transformers, while power

Cable size is calculated based on the load requirements to ensure safety and efficiency.

• Calculate the total load in amperes (A) by adding up the individual loads of all connected devices.

• Determine the voltage (V) of the circuit.

• Use the formula: Cable size (mm²) = (2 x length x current) / (voltage drop x cos θ)

• Consider factors such as voltage drop, ambient temperature, and installation method when selecting cable size.

• F...read more

There are mainly two types of fire alarm systems: Conventional and Addressable.

• Conventional fire alarm system: divides the building into zones with detectors and manual call points connected to a central control panel.

• Addressable fire alarm system: each device has a unique address, allowing for specific identification of the location of a fire or fault.

• Other types include wireless fire alarm systems, aspirating smoke d...read more

The module used in flow switch is a reed switch.

• Reed switch is commonly used in flow switches to detect the flow of liquid or gas.

• It consists of two metal reeds inside a glass tube that are magnetically actuated.

• When the flow of fluid moves the reeds, they come into contact and complete an electrical circuit.

• This triggers the switch to indicate the presence of flow.

• Reed switches are reliable and have a long operational...read more

Synchronization is the coordination of events to operate in unison.

• Synchronization ensures that different components or processes work together smoothly

• It prevents conflicts or errors that may arise from simultaneous actions

• Examples include synchronizing data between multiple devices, coordinating traffic signals, and aligning audio and video in multimedia applications

Transformers cannot be synchronized due to differences in frequency, phase angle, and voltage levels.

• Transformers have different frequency ratings which prevent them from being synchronized.

• Phase angle differences between transformers also make synchronization impossible.

• Voltage levels may vary between transformers, further complicating synchronization.

• Synchronization requires identical parameters in order to operate e

The breaker size on LT side for a 2000kVA transformer will depend on the specific requirements of the transformer and the system it is connected to.

• The breaker size on the LT side of a transformer is typically determined based on the transformer's full load current (FLC) and the system's short circuit current rating.

• Factors such as the type of protection required (thermal, magnetic, or both), the type of system (single...read more

The thickness of medium duty PVC conduit is typically around 1.5mm to 2mm, while heavy duty PVC conduit can range from 2.5mm to 3mm.

• Medium duty PVC conduit thickness: 1.5mm to 2mm

• Heavy duty PVC conduit thickness: 2.5mm to 3mm