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E. Dold & Söhne GmbH & Co. KG
Product: Speed and frequency monitor UH 6937

Speed and frequency monitor UH 6937

E. Dold & Söhne GmbH & Co. KG

Description

Sensorless speed and frequency monitor UH 6937

Now new with safety-related direction of rotation monitoring

In addition to sensorless speed monitoring, the UH 6937 from Dold now also offers safe monitoring of the phase sequence resp. direction of rotation of motors with 3-phase AC voltages. If the motor does not move in the desired direction, the device switches off safely.

The speed and frequency monitor UH 6937 of the SAFEMASTER S series is therefore perfect for applications where the correct direction of rotation is essential, such as in automation processes, compressors, machine tools and wind turbines. The direction of rotation monitoring fulfils PL d / Cat. 2 according to EN ISO 13849-1 and SIL 2 according to EN 61508 while retaining the previous safety-related characteristic data PL e / Cat. 4 and SIL 3 for speed and frequency monitoring.

The device can be operated in a user-friendly way via the four buttons on the front and the LC display, thus enabling simple and time-saving parameterisation - completely without a PC. Up to four operating modes are possible for different configurations of overfrequency, underfrequency, window range and direction of rotation. If the set parameterisation is violated, the frequency monitor switches off dangerous situations in a safety-oriented manner. The UH 6937 from Dold shows its benefits compared to frequency inverters with integrated safety functions when simplicity, flexibility and safety are required.

More products by E. Dold & Söhne GmbH & Co. KG

Extension module RK 6929

Extension module RK 6929

Extension module for Functional Safety up to SIL 3 / PL e

Contact amplification for safety-related semiconductor outputs with testing (OSSD)

If control systems with integrated switching outputs reach their limits in the application, coupling relays and contact extension modules are used. Their task is contact amplification, contact multiplication and, due to the galvanic isolation between input and output, decoupling of the control and power levels.

The centrepiece of the extension module RK 6929 of the SAFEMASTER series, which is only 17.5 mm narrow, is the safety relay OA 5642 from Dold, which also opens up fields of application in the area of functional safety due to its forcibly guided contacts in accordance with IEC 61810-3, for example in mechanical and plant engineering as well as in applications for firing systems in accordance with EN 50156-1. For use within the scope of EN 61010-1, the clearances and creepage distances of the extension module RK 6929 between mains circuits and touchable voltages as well as between mains circuits are dimensioned according to double insulation.

If the current consumption of downstream actuators exceeds the power of the output of a safety controller or light grid, the extension module switches these actuators reliably and potential-free via its relay contacts. The input of the extension module RK 6929 corresponds to the interface type C class 1 in accordance with the ZVEI position paper CB24I and can therefore also be controlled by safety-related semiconductor outputs with testing (OSSD). Single and dual-channel versions of the extension module are available.

In conjunction with a suitable higher-level safety device, which diagnoses the switching status via the forcibly guided NC contacts, the extension module RK 6929 can therefore be used in applications up to Cat. 4 / PL e or SIL 3 and also has UL approval. Removable terminals, in screw and cage clamp technology, complete the advantages of the extension module by enabling convenient installation and simple device replacement.

DC voltage relay UG 9831

DC voltage relay UG 9831

Monitoring of DC systems

Reliable power supply in the voltage range up to DC 1000 V

DC grids are already indispensable in rail technology, data centres, in the power supply of ships or in photovoltaic systems. The possibility of storing DC from renewable energies in battery storage and retrieving it when needed will lead to the further spread of DC grids. For example, in the charging infrastructure of electric vehicles or industry. Whereas electricity used to be supplied from an AC grid – usually across several voltage levels – and converted into DC in a decentralised manner and with losses, a DC grid with central rectification and the integration of renewable energy sources reduces the amount of wiring and conversion losses. For example, the rectification in variable-speed drives of conveyor belts or robotic drives in highly automated production plants is no longer necessary.

The reliability of such power supplies is of the highest importance. In the event of deviations from the target state, control processes must be initiated to stabilise the voltage or, in extreme cases, a shutdown must be carried out. The narrow 22.5 mm DC voltage relay UG 9831 from the VARIMETER series measures the voltage in the wide voltage range from DC 20 to 1000 V and monitors for undervoltage and overvoltage based on the set response thresholds. The response thresholds are precisely set using a latching rotary switch on the front panel, protected against manipulation by a sealable transparent cover and deviations from the setpoint are signalled via potential-free changeover contacts in order to initiate countermeasures. If continuous measurement data is required, the UG 9431 device version with integrated Modbus RTU interface offers easy parameterisation, monitoring and diagnostics of DC systems. Changeover contacts are also available on this device for signalling or controlling signal lamps.

DC systems are gaining in importance due to their economic and ecological advantages. Thus, the DC voltage relays of the VARIMETER series are suitable for many future-oriented applications.