Event Preview: European Utility Week in Vienna, Austria (Nov. 3 – 5, 2015)
At this year’s European Utility Week, the technology leader for bistable relays in energy management, Gruner AG, will present diverse single-phase and three-phase models for smart meters and prepayment systems. The advantage of this switching technology is that only a control pulse is needed. The result is: power consumption and loss due to heat are hardly worth mentioning, the service life of the relay is increased and the switching position is retained even in case of a power failure. In addition, a bistable solenoid shall also be presented as shut-off valve for intelligent gas meters.
Unlike standard relays, bistable, polarised relays only need a single short control pulse of 20 or 30 ms in order to change the switching position. This position is stably retained until the next pulse is sent without requiring any additional power supply. Instead, a magnetic field is applied to ensure that the respective position is reliably maintained. Gruner relays, in addition to that, are characterised by a reduced bouncing, which in turn correlates to a long service life. In terms of design, the relays satisfy the international standards set forth in IEC 61810 Part 1 and VDE 0435 Part 201 and fulfill the short-circuit and longevity requirements according to IEC standards 62053, 62054 and 62055.
Stable switch setting with currents of up to 120 A
The relay models 725 and 736 are well suited for maximum switching currents of up to 100 A, whereas the 723 model is designed for currents of up to 120 A. The relays have a coil with double winding, even though they can also be operated with a single winding, which does decrease power consumption by 50 %. The relays specifically for currents of up to 120A and the three-phase versions have a parallel double contact arrangement. These models are particularly recommended for applications with high load currents or critical temperature patterns, since the impedance and heat loss in such arrangements are significantly lower than in conventional single contact arrangements.
The clearance / creepage of 8 mm, the high maximum switching capacity of up to 30,000 VA and the short response of less than 15 ms are common for all relays. An optimised switching mechanism ensures that the limit switching point is reliably reached such that intermediate states or incorrect positions are ruled out. Thanks to their low weight and compact dimensions, the relays are ideally suited as switch for interrupting the supply to modern, intelligent electricity meters or prepayment modules – especially since many models also have versions with an integrated shunt. Moreover, customer-specific developments are easily possible.
Solenoid valve saves space and energy
The range of smart meter components is supplemented by the bistable solenoid 552 BV, which is specifically designed for use in shut-off valves for gas meters. It is sealed with the aid of a moving elastomer disc. Permanent magnets and a return spring are integrated in the design. The stroke movement is generated electromagnetically in a manner similar to relays, while the effect of the permanent magnets is used for holding the end-of-travel position. The stable positioning is also ensured in this manner without current. A control pulse triggers the switchover in the opposite direction to the holding force. The switchover takes place within a few milliseconds due to the magnetic bistable system. Another important feature is the high resistance to vibrations and shocks.
The energy-saving bistable components shall be presented during this year’s European Utility Week at the stand (A.m44) of Gruner AG. Gruner employees will be on hand to address any questions or inquiries and offer in-depth advice.
By Patrick Spreitzer Head of Relay/Magnets Business Unit
