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Crank, Cam and Speed
These sensors are used for measuring rotational position and speeds, most commonly for crank- and camshaft positions and wheel speeds. The sensors come in two main varieties, magnetic and Hall. They can be distinguished from one another by the number of connecting wires. Magnetic sensors have 2 wires, Hall sensors have 3 wires.
MoTeC supplies the following types:
Hall Sensors
Hall sensors contain a semiconductor Hall effect integrated circuit (IC) and a magnet. There are Hall sensor types available that can be used with a tooth (gear) style trigger wheel for measuring crank angle or wheel speed, and types that use a vaned rotor passing through a Hall sensor gap.
The IC detects changes in the field strength as the vane passes through the sensor gap or a tooth passes the sensor tip. The output voltage changes from low to high (or high to low) when the leading edge of the tooth passes the centre of the sensor.
The vane or tooth material must be magnetically soft, such as mild steel—do not use stainless steel.
Click on the part number to download a datasheet if available.
| Description | Part No | ||
 |
| #59110 | |
 | 7/16 x 20 thread Hall wheel speed sensor | #57102 | |
 | GT101 terminated Hall sensor | #57100 | |
 | GT101 un-terminated Hall sensor | #57101 | |
 | Mount for GT101 Hall sensor | #57099 | |
 | HKZ101 Hall switch to suit vaned rotor | #51121 |
Magnetic Sensors
A magnetic sensor consists of a wound coil of wire that generates a voltage between the sensor wires when the magnetic field strength changes as the tooth passes the sensor. The output voltage amplitude depends on the gap between sensor and tooth and increases with increased speed past the trigger wheel.
Magnetic sensors may be used if the trigger wheel has a large number of teeth as the sensor has a small magnetic pole size. They are often used as crankshaft or wheel speed sensors.
The sensor may be wired for either a rising or falling waveform by reversing the wires. The ECU should be setup accordingly. The tooth material must be magnetically soft, such as mild steel (do not use stainless steel).
Magnetic sensors must use shielded wire to help eliminate unwanted electrical noise and must be mounted rigidly as any vibration can cause false signals.
Click on the part number to download a datasheet if available.
| Description | Part No | |
 | Right angle Delco magnetic sensor | #52001 |
 | Straight Delco magnetic sensor | #51004 |
 | Small grey magnetic sensor | #52002 |
Magnetic Sensor Amplifiers
The Dual Magnetic Converter (DMC) converts magnetic style signals to open collector output signals – a square wave. This makes a typical magnetic sensor behave as a switched or Hall Effect sensor, to make the signals suitable for use with MoTeC ECUs and loggers.
This allows magnetic sensors to be used in applications where previously a Hall sensor was required, for example when using the digital inputs on an ECU to measure wheel speed.
A single DMC can convert two independent magnetic sensor signals.
The DMC comes in 4 versions, each having different trigger levels according to the requirements of the intended application.
- DMC A
This version is intended for fuel flow sensors which have a very low trigger level.
Heavy filtering minimises the possibility of interference, resulting in significant variation of the trigger level with frequency.
- DMC B
This version is intended for engine trigger sensors that have insufficient amplitude to trigger a logic level input.
Minimal filtering avoids delays in the signal. The trigger level does not vary significantly at normal operating frequencies.
- DMC C
This version is intended for ignition system input conditioners, typically used in drag racing, for measuring ignition timing.
- DMC D
This version is intended for magnetic wheel speed sensors.
The signal should be symmetrical around zero volts.
Heavy filtering minimises the possibility of interference, resulting in significant variation of the trigger level with frequency.Click on the part number to download the datasheet.
Description
Part No
DMC A DMC B DMC C DMC D
