Drum switch
A drum switch ( English : cam switch or cam controller ), also programmer , program switch or microcontroller mentioned, an electromechanical component, which serves to electrical is switch to open in a certain time baking and close.
function
A motor, usually a synchronous motor with a downstream reduction, drives a shaft at low speed on which cam disks are arranged. The cams operate the various switches. This is why there is also the name cam switch mechanism .
The compact and inexpensive component is used to automate machines. A typical example of use are household washing machines . The type of control can be referred to as " sequence control ".
Today, drum switches are increasingly being replaced by electronic circuits, because as soon as additional tasks such as messages or alarms are required, the drum switch has disadvantages compared to electronic solutions. In addition, electronic solutions are usually cheaper today than mechanical ones.
If you replace the motor with a manual drive and define different positions, a kind of operating mode selector switch is created. This is how the driving switch in a tram that controls the speed can look like, for example .
Musical instruments
The principle is also used in music boxes and other mechanical jukeboxes. We do not speak of drum switches here, but of pin rollers . No electrical switches are operated, but reeds.
See also
literature
- Günter Boy, Horst Flachmann, Otto Mai: The master's examination in electrical machines and control technology. 4th edition, Vogel Buchverlag, Würzburg, 1983, ISBN 3-8023-0725-9
- A. Senner: Electrical engineering. 4th edition. Verlag - Europa-Lehrmittel, 1965