PULS UF20.241 24V 20A Capacitor Buffer Module 200 ms

A maintenance-free buffer module that rides through short 24 V dips

The PULS UF20.241 is a buffer module for regulated 24 V power supplies. Instead of lead-acid batteries it stores energy in service-free electrolytic capacitors, which is why the datasheet allows operation at ambient temperatures up to +70 C. It can be used to bridge failures of the DC voltage supply, to extend the hold-up time after loss of AC power, or to deliver extra short-term peak current above the current rating of the power supply. No control wiring is required: the module is connected in parallel to the load circuit at any point in the 24 V system.

The buffer module is rated for 20 A buffer current and gives at least 200 ms of buffering at 20 A, longer at lower loads. Several modules can be paralleled to increase either the current or the hold-up time. For multi-minute bridging use a battery-based DC-UPS such as the UB10.241 on this site.

Technical specification

Choosing between a buffer module and a battery DC-UPS

Typical mains dips in industrial plants last from a few milliseconds to a second or two. A capacitor buffer module covers that window without any battery maintenance. At 10 A the datasheet gives typically 670 ms and at 20 A about 310 ms, and the figure rises sharply for light loads, 43 seconds typical at 0.1 A. Battery-based DC-UPS units cover minutes to hours, but need battery replacement every few years. In hot GCC installations capacitors tolerate the temperature better than lead-acid batteries. The module also helps with peak loads: it can supply short current pulses above the rating of the main power supply, which is useful for motor starters and solenoid groups.

Installation notes

• Connect in parallel to the 24 V rail, close to the power supply output; no control wiring is needed.
• Use the selectable threshold: 22.5 V suits most loads, while the supply-minus-1 V option follows an adjusted rail voltage.
• Use the inhibit input if buffering must be disabled during service work.
• Allow the 25 s initial charging time at start-up before expecting buffer function.
• Accessories in the order list: ZM1.WALL panel bracket and ZM14.SIDE side bracket; the datasheet also lists UF20 as accessory for the XT40 and QT40 supplies.

GCC use cases

Buffer modules prevent nuisance PLC resets when large motors start on weak or generator-fed networks and when the upstream supply switches between sources. They are common in pumping stations, compressor houses and utilities where grid disturbances are frequent. See the Power Modules category for supplies and redundancy modules that pair with the UF20.241.

Selection and installation notes

A redundancy or buffer module is selected from the load current, the output voltage and the way the supplies are arranged. Size each supply so one can carry the whole load, keep the wiring from each supply equal in length and cross-section, check the polarity and the module rating against the maximum load and test the changeover by switching one supply off. Allow the heat dissipation and the clearances on the data sheet.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.