MDR-20-12 Power supply Mean Well MDR 20 W 12 V

MDR-20-12 is the smallest power supply in the MDR series for DIN-rail mounting: 20 W, 12 VDC output up to 1.67 A. The universal 85–264 V input lets it run on both 110 V and our 230 V mains without switching. Convection cooling with no fan; -20…+70 °C operating range and IP20 rating for in-cabinet installation. Efficiency is 80%, typical for small 12 V modules.

Typical applications:

• Powering individual 12 V sensors and indicators in small assemblies
• Small relays, interface modules and 12 V logic
• Low-power LED illumination and signal elements

Please note: single output with small voltage trim range; basic protection against overload, short circuit and overvoltage.

Mean Well MDR — economical DIN-rail power supplies for automation cabinets

MDR is Mean Well's series of compact switching power supplies in a slim housing that clips onto a standard TS-35 DIN rail. The line covers an output range from 20 to 100 W across four working voltages — 5, 12, 24 and 48 V DC. It is the workhorse for any control cabinet: compact, more affordable than the heavier-duty DR/SDR families, yet still equipped with the full set of basic protections. The input is universal — 85–264 V AC — so the same unit runs on a 110 V grid and on a 230 V grid without any switch or rewiring.

Model range and ratings

The series has twelve models grouped by rated power. The most popular voltage is 24 V, since that is what most modern PLCs, sensors and relays run on:

• MDR-20 (20 W): 12 V / 1.67 A or 24 V / 1.0 A — for small subassemblies, individual sensors and relays.
• MDR-40 (40 W): 12 V / 3.33 A, 24 V / 1.7 A, 48 V / 0.83 A — the all-purpose mid-size unit.
• MDR-60 (60 W): 5 V / 10 A, 12 V / 5 A, 24 V / 2.5 A, 48 V / 1.25 A — the widest voltage choice in the series, including 5 V for logic and backlighting.
• MDR-100 (100 W): 12 V / 7.5 A, 24 V / 4 A, 48 V / 2 A — the top model with an active power-factor corrector (PFC). Here "100 W" is the frame's nominal rating; the real output power is 90 W (12 V) and 96 W (24/48 V).

Efficiency rises with power and voltage: from 78% on the MDR-60-5 up to 88% — but 88% only on the 40 W frame (MDR-40-24/-48); the 60 W versions at 24/48 V deliver 87%. The top MDR-100 at 48 V likewise delivers 87%. All units are single-output, with a small trimming range on the output voltage.

Protections, cooling and operating conditions

The series is cooled by natural convection — no fan, which means no noise, no dust intake and no moving parts that wear out over time. The housing is rated IP20: designed for installation inside an electrical cabinet, not in the open air. The operating temperature range of the 20/40/60 W models is -20 to +70 °C (with partial derating near the limits), which makes them suitable for unheated cabinets. The top MDR-100 is rated for -10…+60 °C. Every unit carries the basic protection set: overload, short-circuit and over-voltage protection on the output. The MDR-100 additionally features active PFC, which reduces the reactive component of consumption — relevant when several units share one cabinet or when grid-quality requirements apply.

Typical applications

• Powering PLCs and I/O modules: 24 V is the standard for Siemens, Delta and Veichi controllers; the MDR-40 and MDR-60 cover most small and mid-size panels.
• Sensor and actuator circuits: inductive and optical sensors, relays and solenoid valves at 24 V.
• LED backlighting and indication: 12 and 24 V for LED strips and signal towers inside equipment.
• 5 V logic: the MDR-60-5 with its 10 A output, for boards that need exactly 5 V.
• Telecom and low-current nodes: 48 V for the corresponding communication equipment.

How MDR differs from other Mean Well DIN-rail series

Mean Well's portfolio holds several DIN-rail lines, and MDR fills the budget niche. The related DR and HDR families offer a wider spread of power and voltage and better temperature figures, while the NDR series scales up to 240–480 W with active PFC across all models. MDR, by contrast, is the just-enough solution: when you need to power standard 24 V loads up to 100 W in a small cabinet, cheaply and reliably. If you need more power or a three-phase input, look at the higher series; but for a typical task — a PLC, sensors and relays on 24 V up to 100 W — MDR handles it without overpaying. Unlike the enclosed LRS and RSP series, MDR needs no separate space for a "box": it sits on the same rail as the breakers and terminals.

If you are unsure which voltage or power rating suits your specific load, get in touch — we will recommend the exact model based on your equipment's current draw.