Centrifugal governor

The governor is a mechanical element that uses the centrifugal force to control the speed of a machine.

The already known from the mill in governor was introduced in 1788 by James Watt in general mechanical engineering. James Watt used the centrifugal governor to keep the operating speed of the improved steam engine from him constantly. The dimensions ( dynamics of the transient response, vibration and tilt control characteristics ) the governor for this task was the birth of modern mathematical control technology. Previously governor had already been used in mills for the same purpose.

Function and types

Weight as a counterforce

The early design for the regulation of steam machinery was driven by a belt, they used the weight as a restoring force. At rest, the throttle valve of the steam line to the steam engine is opened completely. With movement of the piston of the steam engine the governor begins to turn. By this rotation, the two weights (for example cast iron ) by the centrifugal force are always moved on against the force of gravity upwardly and outwardly. A joint and lever mechanism ( see toggle ), a throttle valve is operated in the vapor line of the machine, which reduces the supply of the vapor to the engine. The machine then passes slowly until a steady state or a constant speed setting. This arrangement is an example of a feedback loop with negative feedback ( The faster the engine runs, the less steam is made ​​available to it ). The problem is the construction by the drive belt: Are there any transfer of the speed signal from the shaft to the controller, eg by a broken drive belt, the controller opens the steam supply completely. The steam engine runs at maximum speed until it is either notabgeschaltet or destroys itself.

Spring as a counterforce

In particular, to achieve a position-independent function was used later mostly feathers as a restoring force.

Examples:

• Dial on older phones: it rotates back centrifugally controlled to keep the pulse train of dial pulses constant; the controller operates on a small drum brake.
• Federnwerk of Gramophone, Film Camera, camera, music box
• Governor with contacts on the armature shaft of DC motors (especially series motors ): the contacts enter via slip rings in the circuit a series resistor -free and keep the speed constant. This makes the high starting torque is obtained.
• In game watches the playback speed is controlled by a centrifugal governor, which represent the weights of rubber friction on one of the end plates of the controller a brake.