Magnetopot Potentiometer Works
SPECTRA SYMBOLWhat is a MagnetoPot
The MagnetoPot is simple, yet elegant in its ability to track motion in a contactless manner. A magnet on the inside of a cylinder, or a magnet on the opposing side of a motion device will guide the built-in magnetics of the MagnetoPot for position location through a potentiometric output.
The MagnetoPot is a sealed potentiometer, in the membrane potentiometer tradition, yet it does not require a wiper/actuator to connect the collector and the resistor. Instead, the MagnetoPot is controlled by an outside magnet, which attracts the magnetic forces within the MagnetoPot to connect to the linear resistor and give linear potentiometer feedback.
The wiper inside the sealed pot is magnetic or ferromagnetic, and will only perform if connected with an exterior magnet.
As opposed to a magnetically-based Reed Switch, which gives simply “open” or “close” signals, the MagnetoPot gives the full linear travel of a hydraulic or pneumatic cylinder.
In liquid level applications, the MagnetoPot can attach to the outside of a liquid tank and give position of the magnet inside the float. No water ingress, no wearing of the part by environment, because the MagnetoPot is outside of the tank.
Design and Construction
The MagnetoPot is made of polyester, fiberglass and kapton, depending on the specification required. It functions as a voltage divider, a resistor or rheostat, as desired by the end-user. By bringing the exterior magnet into a proximity necessary to connect with the internal magnetic attractors, the operator can obtain linear position sensing based on the location of the exterior magnet. As the exterior magnet moves, so does the electrical output of the MagnetoPot.
The MagnetoPot should not be mounted to a ferromagnetic surface.
Just as with the traditional membrane potentiometer, the MagnetoPot gives a linear position feedback with the motion of the external magnet (see example to the left).
Res.-Tol. – ±20%
Lin.-Tol. – ±5%
Resolution: depends upon the exterior magnet strength and distance to the MagnetoPot
Internal Drive Magnet
The Spectra Symbol MagnetoPot uses a N42SH grade, Neodymium, magnet as the tracking magnet of the sensor. Spectra Symbol has partnered with K&J Magnetics (http://www.kjmagnetics.com) to offer mating drive magnets. Contact a member of our Sales Team if you have any questions.
Click here for a N42SH magnet to magnet pull force chart by K&J Magnetics.