Functional redundancy aims at designing multi-parallel safety systems to ensure that all other components continue to operate smoothly should one of them fail. This is why redundant power supplies are separated from each other at the output by diodes or p-Channel Power MOSFETs. All QUEL single voltage devices can be used in redundant mode. Depending on your requirements, we can design systems for hot redundancy (several parallel power converters - if one of them fails, uninterrupted operation is still guaranteed) or cold redundancy (a reserve power converter is switched on in case of an error after a defined short brake).  

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Multiple redundancy

In hot redundancy or hot spare, several systems carry out a function parallel to each other. A system operating in N+1 redundancy consists of N functioning units that are operating at the same time and a non-current carrying unit. Should an active unit fail, the non-current carrying unit takes over its function and additionally feeds into the system. Should another active unit fail, the system is not fully available any longer and is usually regarded as failed. In a homogeneous redundancy, equal components work parallel to each other. With this design, the development effort can be reduced through identical components. It protects the system against random failures caused by ageing or wear and increases overall reliability. In an inhomogeneous redundancy, power supplies of different manufacturers are connected to each other to exclude the remaining risk of failure through development or production errors by the manufacturer.  We offer both hot and N+1 redundancies and recommend the use of homogeneous redundancies.

Convection cooling

To ensure high fail safety of our devices, we abstain from using mobile (electro) mechanical elements such as coolers. Additionally, we keep internal temperatures low by deliberately creating "airy" design. Nevertheless, we also provide 400 W in only 21 TE at 220 mm module depth operating at 48V-DC-DC and an input of 220 Vdc.

Racks

1600 W or up to four power supplies in combination with a display or control unit can be placed in a 3 HE, 360 mm deep or 6 HE, 260 mm deep rack. Various feed-in options from above, below or strain-relieved, from the side are available for our racks. Apart from the DC input, AC or a mixed mode of AC and DC are possible.
The terminal board connected to the rack assumes the electric connection of the up to four power supplies as well as a common input and output filter. Wiring the terminal board, it is crucial that all power supplies have a common reference potential.

Hot plug or hot swap

High-capacity condensers are built into the input and output of a power supply. To stop high peak currents from running through the contacts while charging these condensers, the power from the mains supply is fed in through the front switch integrated in the pull switch.

Redundancy monitoring

Using a N+1 redundancy, one unit is always ready to assure fail safety and replace the power in emergency cases. With a DIP switch on the rack, you can adjust the number of units. N= 2 ... 4. The controller measures the total power of the module and can calculate average and display redundancy behaviour from the number of units and total power. If the redundancy power falls below a certain level, the controller registers an alarm and checks the system every 10 seconds. Via a DIP switch, you can choose whether the devices are to be monitored in pairs or the unit as a whole. Voltages at the up to four outputs are being displayed. The available relay functions are: four DC-OK signals for each output and, for network monitoring up to a maximum of two feed-in grids, redundancy-OK and sum message OK at a maximum of 1 A contact load at 60 V.