MEAN WELL USA Inc.
Mean Well LRS-350-48
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Mean Well LRS-350-48 — 350W 48V enclosed switching PSU
The LRS-350-48 is the 48 volt version of the enclosed switcher most people know as the 24V printer power supply. Same chassis, same 350W class, same screw-terminal block — but it puts out 48V at 7.3A (350.4W) instead of 24V. You want this one specifically when your build runs a 48V bus, not as a drop-in for a stock 24V machine.
What it powers in a 3D printer build
This is a single-rail 48V supply. In a printer that fits two cases:
- 48V motion / stepper bus. High-torque or high-speed setups (e.g. 48V-fed stepper drivers on a CAN/Klipper toolhead or a high-flow CoreXY) run the drivers off 48V for more headroom at speed. The LRS-350-48 feeds that rail directly.
- High-wattage 48V bed or chamber heater. Running a heater at 48V cuts current roughly in half versus 24V for the same power, which keeps wire gauge and connector heating sane on a large bed. 350W is enough for a moderate heated zone or as a dedicated motion supply alongside a separate bed PSU.
Note the standard Voron wiring is 24V for both bed heater and electronics — if you are building a stock-spec Voron 2.4 / Trident, the 24V LRS-350-24 is the part you want, not this. Buy the 48V only if your control board, drivers, and heater are actually specified for 48V. A 5V supply (for the Raspberry Pi / host) is always a separate unit; this PSU does not provide a logic rail.
The honest wiring and safety reality
This is a bare-terminal mains power supply, not a sealed appliance. You are wiring 120/240V line voltage to an open screw-terminal block. That means:
- You provide the fuse and the mains wiring. The LRS ships with no inlet fuse, no power switch, no cord. You add an inline fuse / fused IEC inlet, strain relief, and a proper earth (FG) connection to the case. Earth ground is not optional on a metal-cased mains supply.
- The 115/230 input is a slide switch, not auto-ranging. Input is 90~132VAC or 180~264VAC selected by a physical switch. If you leave it on 115 and plug into 230V mains, you will destroy the supply (and possibly worse). Set it to match your wall voltage before first power-on and check it twice.
- Terminals should be shrouded or boxed. The L/N/FG screw terminals are exposed. In a finished build they belong behind a terminal cover or inside an electronics bay where nothing can touch them live.
If you are not comfortable terminating mains wiring and verifying earth continuity, this is the point to stop and get someone who is. This is the same hardware electricians and panel builders use; it is reliable, but it does not babysit you.
Cooling and behavior
The LRS-350 is fan-cooled with a thermostatic fan (it stays off at light load and spins up when the internal sensor passes ~50°C), so it is not silent under heavy draw — fine inside a printer enclosure, worth knowing if it sits on a desk. Protections are built in, and on this 48V model all three latch off: over-voltage, over-load (110~140% — shuts down and latches off, cycle AC power to recover), and over-temperature. A sustained overload will not auto-recover on the -48; only the separate 150% transient peak (≤1s) uses hiccup mode.
Why this form factor
The enclosed LRS is the commodity workhorse of the Mean Well line: a 30mm-tall steel case, 215 x 115mm footprint, screw terminals, 89% efficient. It is the cheapest reliable way to get a clean DC rail into a printer bay. It is deliberately not a premium part — if you want a DIN-rail slim profile for a tidy control cabinet, that is the HDR series; if you want PFC and higher efficiency for a kit-grade build, that is the UHP series; if you need an encapsulated PCB-mount module, that is IRM. The LRS trades those niceties for price and availability. For most enclosed printer builds, that trade is exactly right.
Verified spec (Mean Well datasheet, LRS-350-SPEC 2025-09-12)
- Output: 48V DC, 7.3A, 350.4W; adjustable 43.2~52.8V
- Input: 90~132 / 180~264VAC switch-selected, 47~63Hz; ~3.4A @ 230VAC, ~6.8A @ 115VAC
- Efficiency: 89% typ.
- Cooling: built-in thermostatic fan; working temp -25~+70°C
- Protections (-48, all latch off — cycle AC power to recover): OVP (latch), OLP 110~140% (shut down and latches off; cycle AC power to recover), OTP
- Size / weight: 215 x 115 x 30mm (8.46 x 4.53 x 1.18 in), 0.76kg
- Safety: IEC/UL 62368-1, BSMI, EAC, BIS; withstand 3.75KVAC I/P-O/P
On clearance — the price below reflects a stock-reduction sale, not a change in the part.
Shipping & Returns
Returns:
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