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

The working principle of current transformers (CT) during a short circuit.Working PrincipleIn normal working conditions, the secondary circuit of a current transformer (CT) is closed and has very low impedance, causing the CT to operate in a near-short-circuit state. When a short circuit occurs, the behavior and characteristics of the current transformer change significantly.Performance during a short circuit Voltage Increase: In a short-circuit scenario, due to the extremely low impedance of th

Using a 12-volt DC transformer (often called an adapter or power converter) in an AC circuit serves the purpose of converting alternating current (AC) to direct current (DC) and reducing the voltage to the desired level. Here are some common uses of a 12-volt DC transformer:1. Powering DC DevicesMany electronic devices and small appliances require DC power to function. A 12-volt DC transformer can provide a stable DC voltage for these devices. Examples include: Consumer Electronics: Such as phon

The impact of a motor losing one phaseWhen a motor loses one phase (i.e., phase failure), it can have a series of adverse effects on the motor's operation. The following are the main characteristics and potential hazards of the motor running with a missing phase:Power output reductionA phase loss in a motor can cause its output power to decrease significantly. This is because a phase loss is equivalent to reducing part of the motor's coils, thereby reducing the ability to generate magnetic field

Single-phase motors require a larger current during startup compared to when they are running primarily due to the following reasons:1.Inertia During StartupDuring startup, the motor must overcome its own static inertia. Since the motor is stationary before startup, a larger torque is needed to overcome static friction and accelerate to operating speed. This process requires a higher current to provide the necessary starting torque compared to normal operation.2.Change in Flux DensityAt startup,

The difference between instantaneous power and power in electrical engineeringDefinition of Instantaneous PowerIn electrical engineering, instantaneous power (Instantaneous Power) refers to the power absorbed by a circuit at a specific moment in time. Its magnitude is equal to the product of the instantaneous voltage and current at that moment. The concept of instantaneous power is mainly applied in power systems with non-linear loads, as the voltage and current waveforms in these systems underg

A two-phase motor (Two-phase Motor) is a relatively uncommon concept, as motors are typically designed for single-phase or three-phase applications. However, theoretically, two-phase motors exist and can be operated according to certain methods. Below is how to operate a two-phase motor:Working Principle of Two-Phase MotorsTwo-phase motors operate similarly to single-phase motors but use two phases of AC power that are 90 degrees out of phase to create a rotating magnetic field. This configurati

A single-phase motor starter (Single-phase Motor Starter) is designed to assist a single-phase motor in starting. Since a single-phase power supply cannot naturally produce a rotating magnetic field like a three-phase power supply, a single-phase motor requires additional assistance to start. Below are the working principles and several common start-up methods for single-phase motor starters:Working PrincipleThe primary function of a single-phase motor starter is to create an initial rotating ma

The single-phase motor can be reversed by the following methods:1.Exchange Power Cord Method: Single-phase motors typically have two power lines, namely live (L) and neutral (N). When these two power lines are swapped, the single-phase motor achieves forward and reverse rotation.Steps: Cut off the power supply to ensure safety. Find the live wire and neutral wire of the motor. Swap the positions of these two wires. Restore power and test the direction of motor operation. Caution:This method is s

The main steps for connecting a three-phase motor are as follows:I. Preparation workDetermine motor parametersBefore connecting a three-phase motor, first determine the motor's rated voltage, rated power, rated current and other parameters. These parameters can usually be found on the motor's nameplate. For example, the nameplate of a three-phase asynchronous motor may be marked with "rated voltage 380V, rated power 15kW, rated current 30A". According to these parameters, a suitable power supply

Here are the methods to find out which phase of a three-phase motor has a fault:I. Observation methodCheck the motor appearanceFirst, observe the appearance of the motor to see if there are obvious signs of damage, such as burned windings or broken casings. If the winding of a certain phase is charred, it is very likely that this phase has a fault. For example, when the motor is overloaded or short-circuited, the winding of the faulty phase may be charred black due to overheating.At the same tim