AmazonBest Flashcards
Explain how a diesel generator produces electricity.
A diesel generator converts mechanical energy into electrical energy. It uses a diesel engine connected to an alternator. The engine burns diesel fuel to create motion, turning a crankshaft. This mechanical energy is transferred to the alternator, which uses electromagnetic induction to generate electricity. As the engine rotates, it causes a magnetic armature to move within a coil of wire, producing alternating current (AC) electricity.
Explain how an Uninterruptible Power Supply (UPS) works.
A UPS is a device that provides emergency power when the input power source fails. It typically includes batteries, supercapacitors, or flywheels to store energy. When the main power is available, the UPS charges its internal storage and passes the power through to the connected devices. If the main power fails, the UPS quickly switches to its internal power source, ensuring a continuous supply of electricity to prevent data loss or equipment damage.
What is the purpose of static bypass in a UPS?
Static bypass is a safety feature in a UPS. A static bypass switch automatically and instantaneously transfers the load to the mains electricity supply when there’s an internal fault or failure with the UPS system.
How does evaporative cooling work and why do we use it?
Evaporative cooling is a process that uses the evaporation of water to cool air. As water evaporates, it absorbs heat from its surroundings, lowering the temperature. This principle is used in cooling systems, especially in hot and dry climates, as it is more energy-efficient compared to traditional air conditioning. It’s commonly used in industrial and residential cooling systems and in data centers to maintain optimal operating temperatures for equipment.
Explain how power gets from a utility down to a rack or server.
Power from a utility is transmitted through a series of substations and transformers, which step down the high-voltage electricity to a usable level. This power is then distributed through a building’s electrical system. In a data center, it typically passes through power distribution units (PDUs), which further regulate and distribute the power to individual racks or servers.
Explain how a Variable Frequency Drive (VFD) works and why we would use them.
A VFD controls the speed of an electric motor by varying the frequency and voltage of its power supply. This allows precise control of the motor’s speed and torque, leading to energy savings and reduced wear on the motor. VFDs are used in various applications like HVAC systems, pumps, and conveyors where variable motor speeds are beneficial.
What is PUE and how is it calculated?
Power Usage Effectiveness (PUE) is a metric used to determine the energy efficiency of a data center. It is calculated by dividing the total amount of energy consumed by the data center by the energy consumed by the IT equipment. A PUE value closer to 1 indicates greater energy efficiency, as it means that less energy is used by cooling, lighting, and other non-IT functions
What is Hertz?
Hertz (Hz) is a unit of frequency in the International System of Units (SI). It measures the number of cycles per second of any periodic event. In the context of electricity, it refers to the number of times per second that the current changes direction (in an AC power supply).
What is an ATS?
An Automatic Transfer Switch (ATS) is a device that automatically transfers a power load from its primary source to a backup source when it senses a failure or outage in the primary source. This is essential for critical systems where uninterrupted power is necessary.
Differences between Real and Active Power.
Real power, measured in watts (W), is the power that actually powers the equipment and performs useful, productive work. Active power is essentially another term for real power. Reactive power, measured in volt-amperes reactive (VAR), on the other hand, is used to maintain the voltage levels required for the equipment to function. The combination of real (or active) and reactive power is apparent power, measured in volt-amperes (VA).
What’s a PDU (Power Distribution Unit)?
A PDU is a device used in data centers and other environments for distributing electrical power to servers, networking hardware, and other equipment. It functions similarly to a large power strip but is more sophisticated, offering features like power filtering, intelligent load balancing, and remote monitoring and control.
What’s an AHU (Air Handling Unit)?
A Air Handling unit is a part of a HVAC system which aims to circulate and condition the air within a building through the use of fans, filters, heating and cooling coils, and
dampers. .
What’s an Automatic and Static Transfer Switch?
An Automatic Transfer Switch (ATS) automatically switches the power source from the primary supply to a backup (like a generator) in the event of a power failure. A Static Transfer Switch (STS) performs a similar function but uses solid-state electronics (such as thyristors) instead of mechanical components, allowing for faster and more seamless switching between power sources.
What are Chillers?
Chillers are a component in HVAC systems used to cool fluids (usually water or a water-glycol mixture). These cooled fluids are then circulated through a building to remove unwanted heat.
What are Cooling Towers?
Cooling towers are devices used to release waste heat into the atmosphere. They are commonly used in conjunction with chillers. The towers allow a small portion of the water being cooled to evaporate into a moving air stream, which provides significant cooling to the rest of the water stream.
