Enclosed metal-case power supplies: picking between 35 W and 200 W
Where an enclosed supply beats a DIN rail one, why the LM200 has a different input range from the rest of the family, and how the six sizes compare.
Who this is for: Machine builders and integrators choosing a metal-case supply, and the people specifying its mounting.
An enclosed switching power supply is a metal box with screw terminals: AC in one end, regulated DC out the other, mounting holes in the base. It is the default when a power supply has to live inside a machine rather than on a DIN rail in a cabinet.
Enclosed or DIN rail?
| Use an enclosed supply when… | Use a DIN rail supply when… |
|---|---|
| The supply bolts to a chassis plate inside a machine | The panel already has a 35 mm rail and the supply belongs next to the PLC |
| You want the lowest cost per watt for a fixed build | You want a serviceable, standard-width part an electrician can swap |
| Space is odd-shaped and a flat box fits better | The layout is standardised across many panels |
Electrically they do the same job. The choice is mechanical and, in practice, about who services the machine.
The MORNSUN LM-R2S sizes
| Part | Output | Rated power | Efficiency | Input |
|---|---|---|---|---|
| LM35-23B05R2S | 5 V / 7 A | 35 W | 86% | 80-305 VAC |
| LM35-23B24R2S | 24 V / 1.5 A | 36 W | 88% | 80-305 VAC |
| LM75-23B24R2S | 24 V / 3.2 A | 76.8 W | 91% | 80-305 VAC |
| LM100-23B24R2S | 24 V / 4.5 A | 108 W | 90.5% | 80-305 VAC |
| LM150-23B24R2S | 24 V / 6.5 A | 156 W | 91.5% | 80-305 VAC |
| LM200-20B24R2S | 24 V / 8.8 A | 211.2 W | 91% | 90-132 / 180-264 VAC |
From the current MORNSUN datasheets; all six are specified with 4000 VAC isolation.
Two things worth noticing
The LM200 has a different input range. Five of the six parts take a continuous 80-305 VAC, so one part number covers 110 V and 230 V networks with no configuration. The LM200-20B24R2S is specified as 90-132 / 180-264 VAC — two bands rather than one continuous range. If your product ships to regions with an unstable or unusually high line voltage, that difference matters; check it against your worst-case supply before standardising on the 200 W size.
Efficiency is not flat across the family. It climbs from 86% at 35 W to about 91% in the middle of the range. On a machine that runs continuously, the difference between 86% and 91% is real heat inside the enclosure, not just an energy bill.
Sizing
The same rules as any supply: add the worst-case load, allow for inrush from capacitive loads, apply the derating curve at your actual internal ambient temperature, then leave 20-30% headroom. Enclosed supplies are often mounted in tighter spaces than DIN rail ones, so the ambient inside the machine — not the room — is the number that counts.
5 V or 24 V?
24 V is the industrial default and the whole family is built around it. The 5 V LM35-23B05R2S exists for logic-only assemblies; if you need both, it is usually cheaper and more flexible to take 24 V and step it down locally with a K78 module.
Written by Raitop. Product parameters are taken from MORNSUN official datasheets; see each product page for the source, the datasheet revision and the date it was checked.
