Choosing the best technology for your product
JAQUET TECHNOLOGY GROUP is in a position to offer a variety of different sensing technologies for heavy-duty environments and package them according to the needs of our customers.
Not every sensing technology is suitable for use in demanding applications, and selecting the best technology is often a challenge. Over the years, we have focused on three core technologies, each of them having its specific advantages.
Variable reluctance (VR) sensors detect a change in the magnetic flux passing through the sensing element, which is composed of a copper coil, a metal pole piece and a permanent magnet. Used in combination with a cogwheel or cograil, the sensor generates an analog electrical signal with a frequency and amplitude that are both proportional to rotational or linear speed. VR sensors are particularly suitable for use in high temperature applications where other sensor technologies cannot be used. Their main disadvantage is that the signal amplitude at low speeds can be very low.
Hall effect sensors are able to sense the amplitude of a magnetic field. They are usually combined with an electronic circuit that switches the output signal from low to high or vice-versa when certain levels of the magnetic field reached. Hall effect speed sensors typically generate a digital output signal with a frequency proportional to rotational or linear speed. Their main advantage is that they can operate down to very low speeds or even standstill. In most cases, their application is limited to ambient temperatures of 125°C or 150°C.
Eddy current sensors combine the advantages of VR and Hall effect sensors. As they typically do not need any electronics at the sensing point, they can be used in higher temperature environments. On the other hand, they generally present a good low speed response and their signal amplitude does not vary over the speed range.