Mean Well LRS-100-24

Mean Well LRS-100-24 — 100W 24V enclosed switcher

A genuine Mean Well LRS-100-24: 24V DC at 4.5A continuous, 108W peak, in the same fanless enclosed package the LRS series is known for. This is the small-wattage tier of the family — the same build and terminals as the LRS-350-24 most people put in a printer, just rated for a fraction of the current.

What it actually powers

At 108W max, this is not the supply to run a printer's heated bed. A Voron, RatRig, or a Klipper-converted Ender pulls most of its current through the bed heater, and on a 24V machine a 235–300mm bed alone wants 200–360W+. That's why printer resellers skip the LRS-100 and start their kits at the LRS-200/350 — it simply can't source the bed amps. We're honest about that: this unit is undersized for a full 24V printer.

Where 108W of clean 24V is genuinely useful in a printer-adjacent build:

• A dedicated rail for 24V electronics and motion — control board, steppers, hotend heater, and fans — on a machine whose bed is heated separately (AC mains bed, SSR + AC silicone heater, or its own larger PSU).
• 24V accessory and lighting loads: chamber LEDs, exhaust/nevermore fans, a small toolchanger dock, or a second-stage enclosure.
• Bench and lab duty — 24V solenoids, small actuators, LED strip, fixturing — anywhere a tidy enclosed 24V brick beats a wall wart.

If you're building a complete 24V printer and this is your only supply, size up to an LRS-200-24 or LRS-350-24 instead. This one is right when 24V at up to ~4A covers the job.

The wiring and safety reality

This is a bare-terminal mains supply. The input side is line voltage on exposed screw terminals — there is no plug, no fuse, and no enclosure beyond the PSU's own vented case. Installing it means committing to the same standards a printer's mains side demands:

• You provide the mains wiring. Line (L), Neutral (N), and Earth (FG) land on the screw terminals. Earth must be connected — the metal case is bonded to it.
• You provide the fuse. Mean Well builds in over-load, over-voltage, and short-circuit protection on the DC output, but the AC input still needs an external fuse or breaker sized for the supply and an inlet you can isolate.
• The terminals must be guarded. In an open frame or printer base, the live input terminals need a cover or a terminal guard so nothing can contact them.
• It's fanless, cooled by convection through the mesh case — give it airflow and don't bury it in a sealed pocket.

None of this is exotic; it's standard control-cabinet practice. But if you want a sealed, plug-and-go brick, this isn't it — this is the open, serviceable, screw-terminal form factor that lets you wire it into a printer or cabinet exactly how you want.

Why this form factor

The LRS enclosed format is the workshop default for a reason: 30mm low profile so it tucks under a printer or along a DIN-equipped panel, a vented metal case that takes abuse, a trim pot to nudge the output, and full-range 85–264VAC input — so there's no 115/230V selector switch to get wrong (the larger LRS-150/200/350 units do have that switch; the LRS-100 auto-ranges). It's TUV/UL-recognized to the current IEC 62368-1 safety standard.

Specs

• Output: 24V DC, 4.5A continuous (100W rated, 108W peak)
• Input: 85–264VAC full range, auto-ranging, 47–63Hz
• Efficiency: ~90%, <0.3W no-load
• Cooling: fanless / free-air convection
• Dimensions: 129 x 97 x 30mm (5.08 x 3.82 x 1.18 in)
• Operating temp: -30°C to +70°C
• Protections: over-voltage, overload, short-circuit; output trim pot
• Safety: UL62368-1, TUV EN62368-1, EN60335-1, EN61558

On sale as a clearance — the lower-wattage tier moves slower than the bed-sized units, so it's priced to clear, not because there's anything wrong with it. It's the same genuine Mean Well part, just the right size for a smaller 24V job.