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A motor protection relay for a high-voltage induction motors feeder trips the breaker when current, stall or earth-fault measurements show a winding or driven-load fault. IEEE Std C37.96 is the usual AC motor protection guide. Plants often choose high voltage for ratings above about 250 HP so operating current and cable size stay lower. That … Read more
Industrial automation uses PCs, PLCs and PACs to run plant machines and process units with far less hands-on work than a mechanized line. A mechanized machine still needs an operator at the controls. Plants specify programmable control when a process needs tighter accuracy, repeatable quality and measured cycle time.Automation sits beyond mechanization: those controllers run … Read more
Enthalpy, entropy and the second law sit on top of the first-law energy balance. Enthalpy is u + pv. Entropy change along a reversible path is dq_rev / T. The second law says the entropy of an isolated system does not fall. This page then covers internal energy, cyclic and arbitrary processes and reversibility. Internal … Read more
Among the usual types of motors, a DC Motor is slowed by regenerative, dynamic or plugging torque. Plants usually apply Electrical Braking for that torque, not Mechanical Braking pads on the rotor. The torque comes from armature voltage and current, not from friction. A DC motor uses these three types of electrical braking: Plugging is … Read more
A power-plant fire protection system is the water supply, detection and extinguishing plant that finds and fights fire on a generating station. Adding megawatts without that plant raises loss and injury risk.Thermal Power Plants in India are often classed as ordinary hazard occupancy by the Tariff Advisory Committee (TAC). Design of the complete fire protection … Read more
Power Plant Fire Protection System (Part-II of III) A fire protection system known as the hydrant system is a pressurised fire-water ring that feeds outdoor hydrants, indoor landing valves, hose cabinets and water monitors. On Indian thermal power plants that ring is usually written to TAC. This page is Part II of the three-part fire-protection … Read more
An MVWS system (short for a Medium Velocity Water Spray System) is a water-based fire protection system of open sprayers and a deluge valve. It cools surfaces and controls burning on light-oil and conveyor hazards, including Indian thermal power plants. MVWS sprayers throw a slower cone of medium-size droplets than HVWS projectors. IS 15325 uses … Read more
What is Instrument Transformer? An instrument transformer is an AC measuring or protection transformer. It scales a high primary quantity down for measurement of electrical quantities such as voltage, current, power, energy, power factor and frequency. The same cores also feed protection of power system circuits and protective relays. Instrument transformers step AC line voltage … Read more
Electrical and electronics engineering materials are the conductors, semiconductors, insulators and magnetic materials used in machines, cables, windings and electronic devices. This page names those four groups and the properties a designer has to specify. Materials science studies composition, structure, processing, properties and performance.For electrical plant that means conductivity, permittivity, dielectric strength, IEC 60085 thermal … Read more
Carnot Cycle The Carnot cycle is a reversible heat-engine cycle between one hot reservoir and one cold reservoir. It has two isothermal legs and two adiabatic (isentropic) legs. No real engine between those two temperatures can beat its thermal efficiency. Carnot thermal efficiency is 1 minus the cold-reservoir absolute temperature divided by the hot-reservoir absolute … Read more