Synchro has a single winding rotor that rotates inside a stator of three windings, much like an electric motor as shown in Figure 1. The primary winding wound around the rotor is excited by an alternating current, which induces currents to flow in three Y-connected secondary windings (oriented 120° apart). The relative magnitudes of secondary […]
LVDT is an inductive device. It has a primary coil, two secondary coils, and a linearly movable core. The primary coil is driven by an AC excitation current, which creates a varying magnetic field. This changing field induces an AC voltage or current in the secondary coil (usually two or three windings) that can be
Characteristics of Strain Gauges The core element of a piezoresistive sensor is the strain gauge. The characteristics of a strain gauge are mainly defined by the gauge dimensions, resistance, gauge factor, temperature coefficient, resistivity, and thermal stability. Gauge dimensions and shape are very important in choosing a right type of strain gauge for a given
When electromagnetic radiation, such as, infrared light, visible light, or ultraviolet (UV) light, strikes a photoconductive material, the resistance of the material decreases. This occurs because the electrons in the valence band of the photoconductive material are excited by the light and move to the conduction band, which increases the material’s conductivity. The amount of
The superposition theorem is a method that allows us to determine the current through or the voltage across any resistor or branch in a network. The advantage of using this approach instead of mesh analysis or nodal analysis is that it is not necessary to use determinants or matrix algebra to analyze a given circuit.
An RCIM sensor is a sensor that results in a change in electrical resistance, capacitance, inductance, electrical field, or magnetic field when it is exposed to a physical, chemical, or biological stimulus. Its output could be a voltage, current, electrical charge, time, or frequency to reflect these changes. Following are the most important characteristics of
For supplying a load in excess of the rating of an existing transformer, another transformer is usually connected in parallel with it since replacing it with a single larger unit is a costly alternative. The cost of a spare smaller rating transformer is also lower. Also, it is preferable to have a parallel transformer in
Printed circuit boards are the building block of most modern electronic devices. They are created to provide mechanical and electrical support for the components. Compared to traditional circuits, printed circuit boards have many advantages. For instance, they are small and light, making them suitable for many modern devices. In addition, the low cost of production
Overheating is a major cause of insulation and bearing failure. 3 phase motor overheating reasons are as under: Line-Caused Motor Overheating Reasons There are four causes of line-caused overheating: overvoltage, low voltage, unbalanced voltage, and a high-resistance connection. Overvoltage: Overvoltage can cause a normally loaded motor to overheat. NEMA standard specifications allow motors a voltage
Encoders are non-contact, optical-based digital devices that are used for measuring displacement. They can be used to measure both linear and rotary displacement. We will concentrate on rotary-type encoders, which are widely used in motion-control applications. Rotary encoders are available as incremental or absolute type. An incremental encoder measures changes in rotation from some datum