Abstract: A circuit configuration is provided for monitoring an electromagnetically actuated device, such as an electromagnetic clutch. The circuit comprises a switchable power source connected to the winding of the electromagnet; the power source supplies a composite voltage formed of a direct voltage part and a periodic alternating voltage part superimposed on one another. Engage and disengage signals are issued for the clutch and the direct voltage part assumes distinctly different levels in dependence on the engage and disengage signals. A precision resistor is connected in series with the winding of the electromagnet and a voltage sensor is connected at a node between the winding and the precision resistor. An evaluation circuit is connected to the voltage sensor for evaluating the alternating voltage part acting on the precision resistor and receiving therefrom information regarding the functionality of the electromagnetic device.

Abstract: A method of monitoring a web for tears occurring inside a dryer of a web-fed printing machine includes measuring the temperature of a running web by a thermal monitoring device in the proximity of an inlet to the dryer, and actuating a safety device when a sudden increase in the temperature of the web is detected by the thermal monitoring device; and device for performing the method.

Abstract: A device for feeding at least one cable through a wall formed with an opening, includes a lockable slide member slidable across the opening for variably reducing the size thereof, and a pair of lips formed of elastic material and located at respective opposite sides of the opening, at least one of the lips being in contact with the slide member.

Abstract: A device for determining and adjusting the position of a web, the device having two sensor units each with a respective light source element directed towards the web and a respective photoelectric sensor element responsive to reflected light, a control unit responsive to respective output signals of the two sensor units, and a device connected to the control unit and fed by an adjusting signal from the control unit for adjusting the position of the web, including reflectors disposed at a side of the web facing away from the sensor units and projecting beyond respective opposite edges of the web, one of the two elements of one of the sensor units being directed towards one of the opposite edges of the web and the other of the two elements of the one of the sensor units being directed to a reference surface, the other of the two elements of the other sensor unit being directed towards the other of the opposite edges of the web and the other of the two elements of the other sensor unit being also directed to a r