Magnetic
pickup (MPU) sensors are devices which can be used in conjunction with
electronic control modules for monitoring of parameters such as speed,
direction of rotation and a variety of alarm conditions.
MPUs are located near a flywheel, camshaft or other type of gear with rotation relative to engine speed. The passing of the gear teeth through the MPU tip (pole) generates a voltage and frequency. This frequency is converted to a speed reference by a control module. It should be noted here that most MPUs will develop similar signals. However, the magnitude and strength of the signal is dependent on the size of the sensor in relation to the gear teeth, the clearance between the pole piece and the gear teeth, and various other factors.
As a general rule of thumb, the following standards should be met:
Take care not to overtighten the lock nut which could result in stretching and damage of the MPU. Once installed, the MPU is wired to the control module according to the manufacturer’s instructions.
MPUs are located near a flywheel, camshaft or other type of gear with rotation relative to engine speed. The passing of the gear teeth through the MPU tip (pole) generates a voltage and frequency. This frequency is converted to a speed reference by a control module. It should be noted here that most MPUs will develop similar signals. However, the magnitude and strength of the signal is dependent on the size of the sensor in relation to the gear teeth, the clearance between the pole piece and the gear teeth, and various other factors.
As a general rule of thumb, the following standards should be met:
- Dimension of tooth top
surface should be equal to or more than the pole piece diameter.
- Tooth height should be equal
to, or more than the space between teeth.
- The space between teeth
should be approximately three times the pole piece diameter.
- Air gap (clearance) between
tooth and pole piece should be between .015" to .030".
Take care not to overtighten the lock nut which could result in stretching and damage of the MPU. Once installed, the MPU is wired to the control module according to the manufacturer’s instructions.