Inductive Transmitter

Assignment

To inform the control unit about the RPM and/or the momentary position of a shaft or, e.g., the flywheel. In the case of the latter, it would be an RPM- and reference mark sensor. You may already know this component under the name "TDC-sensor", however, to also take earlier trigger points into consideration, the point has been brought forward and the description accordingly changed.

Function

When rotating, the impulse wheel (on the left) induces through it's gearing, a voltage in the coil (on the right) which includes a permanent magnet. The sine-shaped array of the cable indicates the resulting alternating current. The oscillation frequency depends on the RPM of the impulse wheel.

Please take particular note

Up to now, we have always described the inductive sensor as being an 'active' sensor, which promptly led to trouble. We have defined the sensor as being active, if it needs no voltage supply because it generates a signal itself. There is however, also the opinion, that an active sensor must have an 'active' signal processing, which of course, a simple iron-core coil cannot provide. After searching through the respective technical literature, it would appear that the expression 'active sensor' has not yet been clearly defined. All this means, is that you can choose whichever version you find fitting. 09/11