Resolvers are a type of rotary electrical transformer or sensor used to measure the angular displacement and speed of rotating objects. They are analogue devices that have digital counterparts. Many resolvers look somewhat like an electric motor, comprising copper windings on the stator and a machined metal rotor. They are widely used in applications requiring precise rotational measurements, such as robotics, aerospace, and industrial machinery.
Resolvers are known for their high accuracy, reliability, and durability, making them ideal for use in harsh environments. They are immune to electrical noise and can function over a wide temperature range. With no contact parts, resolvers have a long operational life. Their versatility and robust performance make them suitable for various demanding applications, ensuring precise and reliable measurements in challenging conditions.
How Does a Resolver Work?
Resolvers operate on the principle of electromagnetic induction. A resolver consists of a stator (stationary part) and a rotor (rotating part), both with windings. An AC voltage is applied to the primary winding on the stator, creating an electromagnetic field. As the rotor turns within this field, the rotor windings induce secondary voltages based on their position relative to the stator.
The resolver generates two output signals (sine and cosine) which vary with the rotor’s position; the sine signal corresponds to the sine of the angle of rotation, and the cosine signal corresponds to the cosine of the angle. These output signals are processed by resolver-to-digital converters (RDCs) to compute the exact angular position, with the ratio of the sine and cosine signals providing a precise measure of the angle. This process converts the mechanical rotational position into electrical signals that can be accurately interpreted.
Resolver vs. Encoder: Understanding the Differences and Their Uses
Resolvers and encoders essentially do the same thing: measure rotary motion and speed, but in different ways. The differences between these two are discussed below.
SDM Magnetics is one of the most integrative magnet manufacturers in China. Main products : Permanent magnet,Neodymium magnets,Motor stator and rotor, Sensor resolvert and magnetic assemblies.
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