Schneider ABL2REM24045K 24V 4.5A Power Supply for Control Loads
Introduction: The Schneider Electric ABL2REM24045K is a 24 V, 4.5 A open-type switching power supply for PLC, sensor and relay control circuits, and its design fit depends on load totals, input planning and cabinet thermal limits.
The ABL2REM24045K provides 24 V at 4.5 A, and its usable design ceiling depends on how PLC, sensor and relay loads stack up against startup current and heat. A PLC rack, sensor blocks and relay coils all need 24 V DC, yet the supply is often sized last and blamed first. The key question is whether 4.5 A and 100 W nominal output carry the actual coil, sensor and startup load with margin for cabinet heat. The model ratings, load ceiling, input range and efficiency, and thermal and altitude limits all affect whether the unit fits the enclosure and the control circuit.
How the 24 V 4.5 A Output Sets the Real Load Ceiling
The ABL2REM24045K is an open-type switching power supply in Schneider Electric's ABL2 series. It provides DC 24 V output with automatic voltage regulation, 4.5 A rated output current, 108 W rated power and 100 W nominal output. Read these ratings together. The regulated 24 V rail suits control circuits, but the supply becomes a problem when the total load is never written down.
1. A 24 V Output Matches Many Control Coils, but Load Totals Still Matter
Twenty-four volts is the working voltage for many PLC inputs and outputs, inductive proximity sensors, photoelectric sensors, relay and contactor coils, signal lamps and small HMIs. The direct voltage match can hide the load total because each device draws only a modest current. A compact PLC with a few I/O cards might take about 0.5 A, a dozen sensor blocks about 0.3 A, and relay coils about 0.03 A to 0.05 A each. Add a 24 V HMI at about 0.5 A and the total approaches 1.5 A. The ABL2REM24045K has ample capacity for that example, but the load list must include every device, including door-mounted lamps and analog transmitters. At 24 V, 4.5 A equals 108 W while nominal output is 100 W, so planning continuous draw near 100 W, about 4.2 A, keeps normal running within the nominal figure instead of at the arithmetic edge.
2. The 4.5 A Rating Shrinks Once Startup Current and Heat Are Included
Startup can erase a comfortable margin. Relay coils and small solenoid valves draw a surge when energised, and devices with capacitive input filters draw a brief current pulse on power-up. Overload protection at 110%–160% of rated current, roughly 4.95 A to 7.2 A, is a protection window rather than a continuous output band. Treat it as a window for short inrush events, not as a continuous 5 A rating. In practice, total steady-state current, add the largest group that switches on at the same moment, and check that the sum stays inside the overload window while the steady figure stays under nominal. A bank of valves opening on machine start belongs in that calculation.
How the Wide AC Input Range and 88% Efficiency Affect Panel Load Planning
The input side lets one part number cover several machine builds. The unit accepts AC 100–240 V single phase and also runs from a 240 V DC source, so a 120 V build, a 230 V build and a DC-fed arrangement can use the same model. The input current changes with voltage. With efficiency rated above 88%, a 100 W output draws roughly 114 W from the line, about 1.14 A at 100 V AC and about 0.48 A at 240 V AC. Size branch protection, terminal blocks and wire gauge around the low-line figure because that is the worst case the panel will see. Efficiency also affects the cabinet thermal budget. The gap between input and output power, roughly 12 W to 14 W at nominal load, leaves the supply as heat, and in a fanless open-type unit that heat moves into the enclosure air. That heat load is small next to a drive or transformer, but in a sealed cabinet it adds to every other heat source. That is why temperature derating matters in compact designs. For a builder using one design across several markets, the wide input range removes a variant, and efficiency above 88% keeps the 24 V rail's contribution to panel heating modest.
How Passive Cooling, Temperature Derating and 5,000 m Altitude Affect Installation
The unit measures 129 × 97 × 30 mm in a metal open-frame body with triangular ventilation holes. It has no fan, so cooling relies on natural convection through those holes. That suits dusty or noise-sensitive panels, but it depends on free air movement: mount the unit vertically where practical, keep clearance above and below the vent pattern, and keep it out of the rising heat plume from transformers and drives. The 4G vibration rating and 10–95% RH non-condensing range cover typical machine mounting. The protection level sets the boundary. IP20 covers solid objects only, so the supply belongs inside an enclosure and away from washdown or dripping water. The Class I design needs a proper protective earth connection. Temperature is the limit that most often catches designers out. The operating range is -30°C to 70°C, but full load applies from -30°C to 50°C; from 50°C to 70°C the output must be derated. The temperature that counts is the air inside the cabinet, not the room, and internal air often runs well above room ambient in a busy panel. If the enclosure idles near 45°C internal on a summer afternoon, it is already close to the full-load line, and any added load pushes the supply into the derated band. Altitude follows the same logic. Up to 5,000 m is the stated altitude limit. At elevation, thinner air carries heat away less effectively and reduces insulation margin, so high-altitude installations should be planned with extra load headroom rather than full-load assumptions. That figure is the altitude limit, and full-load operation at 5,000 m is not unrestricted.
Conclusion
Sizing the ABL2REM24045K comes down to three figures written next to each other: the steady 24 V load total, the largest coincident startup group, and the air temperature at the unit. Keep continuous draw near the 100 W nominal output, treat 4.95 A to 7.2 A as a protection window, plan input wiring around the low-line current, and derate once the cabinet passes 50°C. Kayolo acts as an electronic parts supplier for this model and can verify the part number and anti-counterfeit details. Send your load list, cabinet ambient, altitude and startup details through Get A Quote so the team can confirm the model and packaging and return a written quotation. An electrical components supplier also needs the complete load schedule to compare the supply with the rest of the control circuit, so include it with the inquiry.
FAQ
Q: What 24V control loads fit within the ABL2REM24045K 4.5A output rating?
A: PLC racks with a few I/O cards, inductive and photoelectric sensors, relay and contactor coils, small HMIs, signal lamps and analog transmitters can sit on a 24 V rail of this size. Total the steady current first. At 24 V, the 4.5 A rating equals 108 W with 100 W nominal, so plan continuous draw near 100 W, about 4.2 A, and keep the rest as margin for startup surges. Loads that energise together, such as valve banks, should be counted as one group.
Q: How does the ABL2REM24045K behave above 50°C in a control cabinet?
A: Full load applies from -30°C to 50°C. Between 50°C and 70°C the output is derated, so usable current falls as the air around the unit warms. Measure the air at the supply rather than the room. If the enclosure runs hot, improve ventilation or hold the 24 V load below nominal so the unit works inside the derated band with room to spare.
Q: Can the ABL2REM24045K accept 240V DC input as well as AC 100–240V?
A: Yes. The input is rated for AC 100–240 V single phase with 240 V DC compatibility, so the same unit runs from a standard AC supply or a 240 V DC source. Input current changes with voltage: a 100 W output draws roughly 1.14 A at 100 V AC and about 0.48 A at 240 V, so size wiring and protection around the low-line current.
Sources / References
Switch Mode Power Supply (SMPS) Topologies - Texas Instruments Application Report
IEC 60529:1989+AMD1:1999+AMD2:2013 CSV
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