Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

Winding Resistance Test DefinitionThe winding resistance test of a transformer checks the health of transformer windings and connections by measuring resistance.Purpose of Winding Resistance TestThis test helps in calculating I2R losses, winding temperature, and identifying potential damage or abnormalities.Measurement MethodsFor star connected winding, the resistance shall be measured between the line and neutral terminal.For star connected autotransformers the resistance of the HV side is meas

What is Polarity Test of Transformer ?Polarity Test DefinitionA polarity test of transformer is a method to ensure correct polarity alignment when connecting transformers in parallel.Dot ConventionThe dot convention identifies the polarity of windings in a transformer, showing how voltage is induced. If a current enters the dotted terminal of one winding, then the voltage induced on the other winding will be positive at the dotted terminal of the second winding. If a current leaves the dotted te

Open and short circuit tests are performed on a transformer to determine the: Equivalent circuit of transformer Voltage regulation of transformer Efficiency of transformerOpen Circuit Test DefinitionThe open circuit test of a transformer checks the core losses and parameters of the shunt branch by connecting instruments to the LV side and keeping the HV side open.Open-circuit Test (No-load Test) Steps: Ensure that the transformer is disconnected from the power supply to ensure safety. Open the l

What is Transformer Testing ?Transformer test definitionTransformer testing involves various procedures to confirm the specifications and performance of the transformer before and after installation.Transformer test type Type test Routine inspection Special testTransformer type testIn order to prove that the transformer meets the customer's specifications and design expectations, the transformer must undergo different test procedures at the manufacturer's site. Some transformer tests are perform

What is a Voltage Transformer ?Voltage Transformer DefinitionA voltage transformer, also known as a potential transformer, steps down high system voltages to safer, lower levels suitable for standard meters and relays.Basic OperationThese transformers connect their primary windings across a phase and the ground, operating like other step-down transformers but specifically for voltage management.Standard Secondary VoltageThe secondary voltage output of a typical voltage transformer is generally 1

What is a Current Transformer ?Current Transformer DefinitionA current transformer (CT) is defined as an instrument transformer where the secondary current is proportional to the primary current and ideally has zero phase difference.CT Accuracy ClasThe accuracy class of a current transformer measures how accurately the CT replicates the primary current in its secondary, crucial for precise metering.Working PrincipleCurrent transformers operate on the principle of a power transformer, where the p

What is a Instrument Transformer?Instrument Transformer DefinitionAn instrument transformer is a device that steps down high voltage and current from power systems to manageable levels for measurement and safety.Advantages Large voltages and currents in AC power systems can be accurately measured using instruments with small ratings, such as 5 A and 110–120 V. Lower the cost Which reduces the electrical insulation requirement for measuring instruments and protective circuits and also assures the

What is Isolation Transformer?Isolation Transformer DefinitionAn isolation transformer is defined as an electromagnetic device that transfers AC electrical energy between two circuits while maintaining the same frequency and providing galvanic isolation.Safety and ProtectionEssential for protecting both electronic components and operators from electrical shocks, particularly in environments where equipment is not galvanically isolated.Noise and Interference ControlIsolation transformers help sup

What is a Core Transformer?Air Core Transformer DefinitionAn air core transformer is defined as a transformer that uses air instead of a ferromagnetic core to link the magnetic flux between its windings.Principle of OperationIt operates on electromagnetic induction, where an alternating current in the primary coil induces an emf in the secondary coil.Construction TypesAir core transformers can be cylindrical, with wires wound on a non-metallic cylinder, or toroidal, with wires wound around a pla

What is Earthing Transformer ?Earthing TransformerEarthing Transformeris a special transformer, its main function is to provide an artificial neutral point for the neutral point is not grounded system, easy to use arc suppression coil or small resistance grounding mode, in order to reduce the size of the ground capacitance current when the grounding short-circuit fault occurs in the distribution network, improve the power supply reliability of the distribution system.Earthing Transformer structu