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

To determine if the voltmeter is damaged by measuring high voltage or current, you can check it in several steps. Here are some ways to help you diagnose the status of your voltmeter:Observe the appearanceFirst check the appearance of the voltmeter for obvious signs of damage, such as cracks, burn marks, melted parts, or smoke marks. These may be visual evidence of damage to the voltmeter.Measure the reference voltageIf your voltmeter has a known reference voltage source (such as a standard batt

What is Capacitive Sensor?Capacitive sensor definitionCapacitive sensor is a kind of sensor based on capacitance change to detect the change of physical quantity.Working principleThe working principle of capacitive sensors is based on the definition formula of capacitance: C is capacitance. ϵ is the permittivity of the medium. A is the effective area between the plates. d is the distance between the two plates.Capacitive sensors detect changes in physical quantities by changing one or more of th

Winding Resistance Test DefinitionThe winding resistance test of a transformer checks the health of transformer windings and connections by measuring resistance.Procedure of Transformer Winding Resistance MeasurementFor 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 measured between HV terminal and IV terminal, then between IV terminal and the neutral.For delta connected windings,

Temperature Rise Test DefinitionA temperature rise test of a transformer checks if the temperature increase of its winding and oil meets specified limits.Temperature Rise Test for Top Oil of Transformer First, the LV winding of the transformer is short-circuited. Then one thermometer is placed in a pocket in the transformer top cover. Other two thermometers are placed at the inlet and outlet of the cooler bank respectively. The voltage of such value is applied to the HV winding that power input

Dielectric Test DefinitionThe dielectric test of a transformer checks the insulation’s ability to handle voltage without breaking down.Separate Source Voltage Withstand Test of TransformerThis dielectric test checks the main insulation’s ability to withstand voltage between the winding and the earth.Procedure All three line terminals of the winding to be tested are connected together. Other winding terminals not under test and the transformer tank should be connected to the earth. Then a single-

Vector Group Test DefinitionThe vector group test of a transformer checks the phase sequence and angular difference to ensure transformers can operate in parallel.Vector Group Test of TransformerThe vector group of a transformer is essential for successful parallel operation of transformers. Every electrical power transformer must undergo a vector group test at the factory to ensure it matches the customer’s specified vector group.The phase sequence, or the order in which phases reach their peak

What is a First Order Control System?First Order Control System DefinitionA first order control system uses a simple type of differential equation to relate inputs and outputs, focusing on the first derivative of time only.The transfer function (input-output relationship) for this control system is defined as: K is the DC Gain (DC gain of the system ratio between the input signal and the steady-state value of output) T is the time constant of the system (the time constant is a measure of how qui

What is an Radiation Pyrometer?Radiation Pyrometer DefinitionA radiation pyrometer, a non-contact temperature sensor, measures temperature by detecting an object’s naturally emitted thermal radiation. The radiation depends on the object’s temperature and emissivity—the ability to emit heat compared to a perfect black body. Q is the thermal radiation ϵ is the emissivity of the body (0 < ϵ < 1) σ is the Stefan-Boltzmann constant T is the absolute temperature in KelvinRadiation Pyrometer Comp

What is Bimetallic Strip Thermometer?Bimetallic Strip Thermometer DefinitionA bimetallic strip thermometer is defined as a device using two bonded metal strips with different thermal expansion rates to measure temperature.Working PrincipleThe basic structure and principle of a bimetallic strip thermometer are shown in the figure below. The bimetallic strip consists of two metal strips with different coefficients of thermal expansion, such as steel and brass. The steel strip has a lower coefficie

What is an Watt Hour Meter?Watt-Hour Meter DefinitionA watt-hour meter is defined as a device that measures and records the electrical power passing through a circuit over a period of time.Tampering and SecurityA common tampering method involves attaching a magnet to the outside of old energy meters. Using capacitance and inductive loads can also reduce the rotor speed.The most modern meter can store up the previous value with time and date. So the tampering is avoided. Utilities install remote