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Emily Jones
Emily Jones
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Emily JonesMember
PF = kW / kVA. Measured using wattmeters, ammeters, voltmeters, or power analyzers during open/short circuit tests or field diagnostics.
Emily JonesMemberTransformers are rated for power output in kVA or MVA based on continuous operation under specified temperature rise and cooling conditions. Nameplates show rated voltages, currents and frequency, from which apparent power is computed. For example, a three phase transformer with rated line voltage V and current I has rating S = ?3 × V × I. The rating assumes particular cooling class and ambient temperature. Some transformers also have overload or dual ratings for different cooling stages, such as ONAN and ONAF, with higher kVA when forced cooling is active.
January 26, 2026 at 3:29 pm in reply to: Why is online DGA monitoring used for power transformers? #332075Emily JonesMemberDissolved Gas Analysis tracks gases produced by thermal and electrical events. Online monitoring enables early detection of arcing, overheating, and insulation breakdown.
January 26, 2026 at 1:10 pm in reply to: Why is a step up power transformer required in long distance power transmission? #332053Emily JonesMemberStep-up transformers reduce current for a given power, lowering resistive losses and enabling economical long-distance transmission.
January 25, 2026 at 5:49 am in reply to: What does power core refer to in transformer construction? #331801Emily JonesMemberThe power core refers to laminated steel (or amorphous metal) assemblies that provide the magnetic path. Core quality influences losses, noise, efficiency, and thermal behavior.
January 24, 2026 at 3:40 pm in reply to: What applications use Siemens power transformers in utility systems? #331691Emily JonesMemberSiemens units are found in EHV substations, renewables interconnections, industrial substations, and urban distribution networks worldwide.
January 24, 2026 at 11:33 am in reply to: What types of power transformer connections are used in three-phase systems? #331659Emily JonesMemberSame: star (Y), delta (?), zig-zag (Z), with vector group phase shifts (e.g., Dyn11, YNd1).
January 24, 2026 at 11:18 am in reply to: How do transformers manage electrical power conversion? #331657Emily JonesMemberSame physical principle: magnetic coupling and turns ratio determine voltage and current relationships.
Emily JonesMemberRatings are expressed in kVA or MVA for apparent power, plus voltage class, cooling class, frequency, and impedance.
January 23, 2026 at 8:54 pm in reply to: Are power transformers dangerous for nearby personnel? #331535Emily JonesMemberPower transformers can present hazards due to high voltage, high current, elevated temperature and stored energy. Risks include electric shock, arc flash, thermal burns and oil ignition in oil-filled units. Modern installations mitigate these risks through grounded enclosures, fencing, clearance zones, fire suppression, interlocks and warning signage. Condition monitoring and routine testing further reduce failure probability. With proper PPE, lock-out/tag-out procedures and safety standards, the residual risk for trained personnel remains low.
Emily JonesMemberOverload, internal faults, gas buildup from insulation breakdown, or oil ignition can breach tanks and cause explosive failure.
January 23, 2026 at 11:39 am in reply to: What formula is used to calculate transformer output power? #331439Emily JonesMemberOutput apparent power S_{out} = V_2 I_2, with real power P = S cdot text{pf}.
January 23, 2026 at 4:03 am in reply to: What determines maximum power for a transformer under load? #331387Emily JonesMemberMaximum power is limited by thermal and insulation constraints rather than just kVA math. At rated voltage and frequency, winding and core losses create heat; the transformer can only dissipate so much before insulation ages rapidly. Cooling class, ambient temperature, hot-spot temperature limits, and insulation class define how much current can safely flow. Short-term overload curves allow temporary higher loading, but continuous power must keep temperatures within design limits to avoid accelerating aging or triggering protective relays.
January 22, 2026 at 9:18 am in reply to: What is the working principle of a power transformer? #331219Emily JonesMemberIt operates on electromagnetic induction: alternating flux in a laminated core induces voltage in secondary windings proportional to turns ratio.
January 22, 2026 at 2:58 am in reply to: What does transformer power factor testing evaluate? #331129Emily JonesMemberIt evaluates dielectric losses in insulation systems. Elevated PF indicates moisture, contamination, or insulation aging; trending PF supports predictive maintenance and refurbishment planning.
January 22, 2026 at 2:42 am in reply to: What does a power transformer do in an electrical power grid? #331125Emily JonesMemberIt enables voltage transformation between generation, transmission, and distribution segments, supporting efficient long-distance power flow and safe end-user delivery.
Emily JonesMemberIt changes distribution voltage levels along feeders to deliver appropriate service voltages to customers.
January 21, 2026 at 7:51 pm in reply to: How is a transformer on power pole inspected for partial discharge and moisture ingress? #331026Emily JonesMemberInfrared scans, ultrasonic testing, oil sampling, and bushing checks reveal PD activity and moisture-related insulation decay. Utilities may perform vacuum drying or oil replacement.
January 21, 2026 at 6:31 pm in reply to: What does testing power transformers involve in industrial maintenance? #331006Emily JonesMemberIndustrial programs include dielectric, mechanical, and thermal assessments to ensure compliance, reliability, and safety during service.
January 20, 2026 at 11:47 pm in reply to: How does a transformer power plant link generation output to high voltage transmission? #330715Emily JonesMemberGenerator step-up transformers raise generator bus voltage (e.g., 11-20kV) to 110-400kV for long-distance transmission with reduced I²R losses.
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