Industrial DIN-Rail Power Supply Unit

01

Turn the nameplate wattage into a cabinet rating

MORNSUN’s LIF240-10BxxR2 / -QQ datasheet, revision 2024.07.30-B/2, includes both coefficients and plotted curves. Unless stated otherwise, its measurements use 25 °C ambient, humidity below 75% RH, nominal input and rated output load. The unit uses free-air convection; a closed installation needs the maker’s application review [1].

1. Add up the continuous load

   Sum the steady current of PLCs, I/O, sensors, relays and HMIs on the rail. Keep inrush and short peaks for the next step.

2. Check peaks against the boost window

   The datasheet states 150% peak output for 3 seconds. Keep the peak amplitude and duration separate from the steady load, and obtain the permitted repetition/recovery duty from the maker; the sheet does not establish an unlimited sequence of 3-second boosts [1].

3. Apply temperature derating

   At 230 VAC input, the 24, 48 and 55 V models lose 2.5% of output per °C between +60 and +70 °C; the 12 V model loses 1.25% per °C from +50 °C [1].

4. Apply low-line derating

   The 115 VAC curve starts temperature derating at +45 °C, at 2.0% per °C. A separate curve, at 25 °C ambient, reduces output to 90% at 85 VAC or 120 VDC and reaches full output at 100 VAC or 140 VDC. The note requires derating at low input; do not invent a rule for multiplying or adding simultaneous derating factors [1].

5. Correct for altitude

   Above 2000 m the permissible ambient temperature drops by 5 °C per 1000 m; the series is rated for operation up to 5000 m [1].

6. Leave the result with margin

   Compare the derated capacity with continuous load and the specified peak duty. If capacity is insufficient, select a suitable larger supply or independently supplied circuits. Parallel connection of outputs needs an explicitly supported sharing or redundancy arrangement; it is not assumed for this series.

The first three rows are arithmetic from the published slopes; the fourth reads the cold-temperature curve. They treat one stated condition at a time. The datasheet’s plots have been visually checked, but they do not establish a combined low-line/high-temperature/altitude formula or the acceptable boost repetition duty [1].

02

Choose the output voltage, then read the column that changes

The four listed voltage models use a metal case specified as 124 × 41 × 110 mm and a typical mass of 650 g. The sheet names AL5052 and SPCC for the case. Electrical values below retain their typ./max. distinction; efficiency is a typical value at 230 VAC under the stated test basis [1].

03

Separate the conversion blocks from the model’s serviceable interfaces

This is a functional reference, not a MORNSUN manufacturing BOM. TI’s 2017 TIDA-01494 industrial reference design illustrates the rectifier/PFC, isolated switching stage, synchronous output rectifier and feedback path. It is a different, 480 W design. The R2 datasheet identifies external terminals, controls and case, but does not disclose its internal component part numbers, counts or magnetic materials [4] [1].

Do not open the R2 to identify these internal parts: its manufacturer prohibits opening or repair. Use the external drawing, ratings and report when selecting a replacement or checking an incoming unit [1].

04

Know how the unit behaves when something goes wrong

Fault behaviour decides whether a machine restarts on its own or needs a technician, so read these lines before choosing protection downstream.

Short circuit

Hiccup mode: the unit runs constant current for 1 s, switches off for 10 s and repeats, recovering by itself within 10 s once the short is removed [1].

Overload

At 230 VAC, the datasheet’s over-current field states self-recovery at 110–200% of rated current for normal/high temperature and ≥105% at low temperature. These wide limits are not a selective-coordination design for downstream protection [1].

Over-voltage

Hiccup with self-recovery after the fault clears; the 24 V model trips at or below 35 V [1].

Over-temperature

A typical over-temperature-protection value of 80 °C is listed at 230 VAC and rated load. It is a protection datum, not permission for continuous operation at 80 °C or a guaranteed trip temperature [1].

DC OK relay

Contact rated 30 VDC / 1 A resistive; closed when output is normal and open when output falls below 90% of nominal [1]. Wire it to a PLC input to log supply faults.

Mains dip

Hold-up time is listed as a typical 20 ms value. The field provides no guaranteed minimum or explicit line/load condition beyond the sheet’s default test basis. It cannot establish an exact outage threshold for every cabinet; request the required hold-up test with input, load and acceptable output limit [1].

05

State the measurement basis alongside each electrical field

Nameplate values, typical test results and safety-test values answer different acceptance questions. These fields apply to the cited R2 example; limits for another supply require its own datasheet.

06

Install it so the ratings still hold

Derating figures assume the mounting the maker describes. These installation conditions come from the same datasheet [1].

• Above 50% permanent load, leave 20 mm above and below and 5 mm on each side; widen the side gap to 15 mm next to another heat source such as a second power supply [1].
• Earth through the PE terminal on the input block, not a housing screw; the case must be connected to system PE in operation (safety class I) [1].
• Use the specified copper-wire temperature rating: at least 90 °C for ambient ≤60 °C and at least 105 °C above 60 °C. Minimum insulation voltage is 300 V at input and 60 V at output. The wire note extends to 85 °C, but the product operating limit remains +70 °C with derating; wire selection does not expand it [1].
• The series is designed for natural air cooling; for a closed environment the maker asks you to consult its application engineers [1].
• Indoor use only, pollution degree 2, overvoltage category II; do not install where condensation can occur [1].
• Output is trimmed with the ADJ potentiometer, clockwise to increase [1]; record the set voltage on the cabinet drawing.
• The manufacturer instructs isolating input and preventing inadvertent re-energization before work, and prohibits opening, modifying or repairing the unit. Internal functional blocks below are selection context, not a repair procedure [1].

07

Verify the certificates yourself

The datasheet lists IEC 62368-1 safety approval with a CB report, EN 62368-1 and EN 61558-1, and states that the design refers to UL 61010-1, UL 61010-2-201 and UL 62368-1 [1].

Ripple/noise is measured with 20 MHz bandwidth using the tip-and-barrel method and 47 µF electrolytic plus 0.1 µF ceramic capacitors in parallel at output. The sheet says its index-test methods follow company standards. Agree these conditions before comparing a report with the 24 V entry’s 60 mV typical /120 mV maximum figure [1].

08

Copy this RFQ and fill in the brackets

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Product: DIN-rail AC/DC power supply, quantity [pieces]
Output: [24 V] / [  ] A continuous, peak [  ] A for [  ] s, repeated every [  ] s
Input: [230 VAC / 115 VAC / DC  V]; lowest expected mains [  ] V
Cabinet: max ambient [  ] °C, altitude [  ] m, closed or ventilated [ ]
Signals: DC OK relay [required], contact rating [ ]
Capacitive load on output: about [  ] µF
Coating: [standard / QQ], indoor/non-condensing installation [ ]
Certificates required: [CB report IEC 62368-1 / UL listing with file number / CE / other]
Documents: datasheet revision, derating curve for the ordered model, guaranteed hold-up test conditions, ripple test method and batch report
Delivery to [country], target date [date]

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