Siemens Aktiengesellschaft

Siemens Energy Global Gmbh & Co. Kg

Wolf-Martin Rasenack

Stefan Ingo Meier

Christian Merkel

Martin Meinardus

Werner Czerny

Mathias Rebling

Iuliu Vlaic

Markus ERDMANNSDÖRFER

A method for fail-safe monitoring of the speed of a drive that includes at least a converter, a motor, and a rotational speed sensor, wherein a target rotational speed is specified to the drive and an actual rotational speed is sensed via the sensor, where a substitute rotational speed is calculated and three plausibility checks are performed in a safety program of a safety CPU, the substitute rotational speed being determinable, for example, from the initial frequency of a converter or from the quotient of EMF and magnetic flux, in each case two of the following three values being checked: target rotational speed, actual rotational speed and substitute rotational speed to achieve a high safety integrity level while avoiding disadvantages of conventional solutions, and because the calculated substitute rotational speed is independent of the sensor, even sensor errors that are difficult or impossible to detect via conventional solutions become detectable.

Fail-safe speed monitoring of a drive

A method for operating a machine for producing and/or processing a material web, wherein a first drive unit is supplied by a converter with a current, a vibration propagating over the material web is captured via the first drive unit, the vibration is measured and transformed into a measurement signal that is examined for presence of a signature that differs from the basic waveform of the current, a web tear is thus identified if the signature propagating over the material web is missing during the evaluation of the electrical measurement signal, whereby no further sensors, in particular optical sensors, are required to capture the measurement signal, and the measurement also occurs independently of a torque, a speed or speed development of drive motors over time and, moreover, the detection of the web tear does not require a comparison measurement at the machine without a continuous material web.

Method for operating a machine for producing and/or processing a material web

A drive roller, driven by a motor, moves a material web on a set of rollers. The present rotational speed of the motor is detected. A current web speed is determined from the detected rotational speed and a diameter of the drive roller. The current web speed is compared with a specified target speed value and a specified threshold speed value of the web speed.

Monitoring web speed of material web

A method operates a conveyor installation having a belt and at least one drive drum for driving the belt. The torque acting on the drive drum is controlled, in order to alter the speed of the belt, within a time window that is defined by a first rotational speed of the drive drum and a second rotational speed of the drive drum.

Growing community of inventors

Marloffstein, Germany

Wolf-Martin Rasenack