Zerorest provides sensor and systems design and applications assistance - magnetic, hall, magnetostrictive, magnetoresistive, geartooth sensors

Rate meters, Tachometers, Switches, Circuit boards, Speedometers, Odometers  


Zerorest Sensor Services

       In the late eighties I was asked to develop speed sensing for LSHT (low speed high torque) gerotor motors on salt and sand spreaders used for snow and ice control. The sensors are  for the motor driving the chain/belt in the bottom of a vee bottom truck or for the motor on an auger across the tailgate. These drives feed the medium onto a slinger disc driven  by a motor with a sensor. A controller matches the speed of the drive motors to the ground speed of the vehicle to control the media spread per lane mile. 

     Most sensors in use were analog. They have the disadvantage of not providing a signal at very low speed. No signal was produced at low speed when accelerating from a stop, a difficulty in intersections. I decided to seek out a digital or pulsed signal. My research led me to a hall effect sensor and motor with magnetic poles around the circumference.

    Sensors were typically on the ends of augers and exposed to physical damage and excess corrosion. The LSHT motors had the advantage of having the sensor mounting clamped between the motor and the driven device offering a compact protected location..

     Thousand of these motors have been used in the field successfully. My goals are to improve upon this success with improvements in reliability, ease of assembly, fit, mounting options, and in the number of pulses produced. New sensor technologies for old or new uses are also available.


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