Product category:
UPSs
News Release from: Puls UK | Subject: SLV20.200
Edited by the Electronicstalk Editorial
Team on 25 September 2002
Buffer unit covers 80% of power
interruptions
A novel buffer unit provides a battery-free design for a secure power supply in case of AC power faults.
The concern and sensitivity among industrial users with regard to power quality continues to grow, especially in light of the impending liberalisation of energy markets worldwide Until now, only battery-based DC-UPS systems were able to provide supplementary power in the event of mains failures
This article was originally published on Electronicstalk on 3 Jul 2008 at 8.00am (UK)
Related stories
DIN-rail supplies have voltage drops covered
The latest addition to the Dimension range of DIN-rail power supplies from Puls offers an answer to the age-old problem of the voltage drop inherent in longer cables.
Miniature supplies on the DIN rail
The ML15 range of DIN-rail power supplies offers a choice of 5, 12 and 24V DC single outputs in a tiny 22.5 x 75 x 91mm housing.
However, these systems require regular maintenance, and the industrial fitness of batteries is limited.
Some manufacturers specify the lifetime of the batteries to be just one year, even under the optimistic assumption of 40C ambient temperature.
The aging process of batteries cannot be monitored reliably - with the result of unit failure in case of need.
Further reading
Supplies cut the cost of DIN-rail power
The C-Dimension Series of DIN-rail power supplies are considerably lower in cost than standard units, but with only minor reductions in functionality.
DIN-rail supplies come with conformal coating
Coating provides higher operational safety and reliability in a number of installation environments.
Industrial supply saves space on the DIN rail
DIN-rail-mounting power supply replaces control transformers commonly used for low-power control voltages where a neutral wire is not available.
On a quest to remedy this situation, Puls has developed a new, battery-free design for a secure power supply in case of AC power faults.
The buffer unit SLV20.200 is simply added in parallel to a regulated DC 24V power supply in the load circuit.
The unit contains electrolytic capacitors to store energy and is therefore - in contrast to regular DC-UPS systems - maintenance free.
There is no additional control wiring, and no need for additional battery space.
The buffer unit extends the hold-up time of the DC circuit by a guaranteed minimum of 0.2s at 20A load current.
According to statistics, this period of time covers more than 80% of all mains faults.
The user can therefore simply bridge any power gaps with the buffer unit.
In case of persistent power outages, the buffer unit can substitute the power supply until all process data have been saved for a system restart and a controlled system shutdown has been carried out.
The buffer unit will only be forcibly shut down after 4s.
It can supply at least 1A for this long period of time.
Several SLV20 may be operated in parallel to increase the buffered current or to extend the buffer time.
The buffer unit can be optimally adapted to the power source in the relevant DC circuit.
The backup threshold of the buffered voltage can be set with a front jumper on the device.
The relative threshold Uin-1V is for example used in circuits with voltages higher than 24V, which are common where power losses through long connections are found.
With this setting, the buffer unit will be activated by voltage drops faster than 0.54V/s and exceeding 1V.
The threshold setting "22.5V fixed" will activate the unit at 23V terminal voltage, the voltage is then buffered at 22.5V.
This setting is best for universal use with different 24V power supplies.
A major advantage for many applications lies in the ability to monitor the unit status precisely: the buffer unit signals buffer charging and discharging via the "ready" and "active" signal outputs as well as a front side status LED.
The buffer capacitor array may also be forced to discharge via an "inhibit" input - in this way; an external control could suppress the buffering operation and force an immediate shutdown of the DC circuit.
The readiness of a DC-UPS depends on the status of its batteries, which in turn changes with age and temperature.
The SLV20, on the other hand, always works reliably, in a temperature range from 0 to 60C.
It is an ideal supplement for any DC power supply around the world, wherever an absolutely reliable power source is required.
The simple installation - snap the unit onto the DIN rail and wire it parallel to the power supply - makes it very easy not only to equip new machines and systems with the buffer unit, but also to retrofit existing installations with it.
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