Mean Well LRS-450-5 Power Supply
5V 75A · 375W rated — not 450W · fan-cooled with 50°C on/off control · 225 × 124 × 35mm · UL 62368-1 · 1.5M hour MTBF
A 5V supply whose model number overstates its output by 75W — 75A at 5V is 375W, not the 450W the series name implies. Here is the verified datasheet figure, the fan threshold you need to design around, and the protection behaviour that differs from the LRS-350 — supplied by Excelled Display, LED display manufacturer and component supplier for global B2B integrators.
Mean Well LRS-450-5 Power Supply at a Glance
What is it? The LRS-450-5 is the 5V model in the MEAN WELL LRS-450 series of enclosed single-output switching power supplies. It delivers a regulated 5V DC output at up to 75A from a 90–132VAC or 180–264VAC input selected by switch, in a 225 × 124 × 35mm metal case with a covered 9-pin screw terminal block and a built-in cooling fan.
How many watts is it? 375W — not 450W. This is the single most important thing to get right about this model, and the one most reseller listings get wrong. 5V multiplied by 75A is 375W. The other voltages in the series — the 12V, 15V, 24V and 36V models — do reach the 450W the series is named for, because they carry lower current at higher voltage. The 5V model does not. If your power budget was calculated on 450W, it is 75W short.
Does it have a fan? Yes. Unlike the fanless LRS-200-5 and the LRS-150, this model uses forced air cooling through a built-in fan with on/off control. The fan switches on when the internal sensor reaches approximately 50°C and off again at approximately 40°C, so it is silent at low load and audible once the cabinet warms up.
What does it take in? 90–132VAC / 180–264VAC by switch, or 255–370VDC with the switch set to 230VAC, at 47–63Hz. Typical AC current is 10A at 115VAC and 6A at 230VAC, with inrush current of 35A at 115VAC and 60A at 230VAC cold start.
What protections are built in? Overload at 105–150% of rated power using constant-current limiting with shutdown after three seconds, over-voltage at 5.75–6.75V, and over-temperature shutdown. Unlike the hiccup-mode LRS-200 and LRS-350, these protections latch off — the unit must be re-powered, and the datasheet specifies a cool-down period before restart.
What is it used for? Larger 5V LED cabinet sections, high-current signage and lighting loads, and industrial equipment where 60A from an LRS-350 is not enough but a 600W supply is more than the budget allows. Configuration, MOQ and pricing from our sales team.
LRS-450-5 vs the Rest of the LRS-450 Series: Only the 5V Model Falls Short of 450W
The LRS-450 series contains six models. Five of them reach 450W or more. The 5V model does not, and the reason is structural: every model in the series shares a 125A output-current ceiling, so wattage falls as voltage falls — and the 5V model is the lowest voltage in the range.
| Model | Output voltage | Rated current | Rated power | Shortfall vs 450W |
|---|---|---|---|---|
| LRS-450-5 | 5V | 75A | 375W | −75W |
| LRS-450-12 | 12V | 37.5A | 450W | exactly 450W |
| LRS-450-15 | 15V | 30A | 450W | exactly 450W |
| LRS-450-24 | 24V | 18.8A | 451.2W | above rating |
| LRS-450-36 | 36V | 12.5A | 450W | exactly 450W |
| LRS-450-48 | 48V | 9.4A | 451.2W | above rating |
LRS-450-5 Specifications: The Datasheet Parameters That Matter on a Screen
Transcribed from the MEAN WELL LRS-450 specification sheet (LRS-450-SPEC, revision dated 2025-09-12) for the 5V model. All parameters not otherwise noted are measured at 230VAC input, rated load and 25°C ambient.
| Parameter | LRS-450-5 specification |
|---|---|
| DC output voltage | 5V, adjustable 4.75 ∼ 5.5V |
| Rated current | 75A, current range 0 ∼ 75A |
| Rated power | 375W — the series name says 450W; the 5V model does not reach it |
| Ripple & noise (max.) | 200mVp-p, measured at 20MHz bandwidth with a 12″ twisted pair terminated by a 0.1µF and 47µF parallel capacitor |
| Voltage tolerance | ±2.0% (includes set-up tolerance, line regulation and load regulation) |
| Line regulation | ±0.5% |
| Load regulation | ±2.0% from 0% to 100% rated load |
| Set-up / rise time | 1500ms, 50ms/230VAC at full load, measured at cold start |
| Hold-up time (typ.) | 16ms/230VAC, 12ms/115VAC at full load |
| Input voltage range | 90 ∼ 132VAC / 180 ∼ 264VAC selected by switch; 255 ∼ 370VDC with the switch on 230VAC |
| Input frequency | 47 ∼ 63Hz |
| Efficiency (typ.) | 87% at 5V (series spans 87% at 5V to 92% at 36V and 48V) |
| AC current (typ.) | 10A/115VAC, 6A/230VAC |
| Inrush current (typ.) | 35A/115VAC, 60A/230VAC cold start |
| Leakage current | <2mA / 240VAC |
| Overload protection | 105 ∼ 150% rated output power; constant-current limiting, unit shuts down after 3 seconds; re-power on to recover |
| Over-voltage protection | 5.75 ∼ 6.75V; shuts down output, re-power on to recover |
| Over-temperature protection | Shuts down output, re-power on to recover |
| Cool-down before restart | 3 minutes (typ.) required once any protection has triggered |
| Fan control | RTH3 threshold: fan on at ~50°C, off at ~40°C |
| Cooling | Forced air cooling by built-in fan (on/off controlled) |
| Working temperature | −20 ∼ +70°C with derating (curve specified for horizontal mounting) |
| Working humidity | 20 ∼ 90% RH, non-condensing |
| Storage | −40 ∼ +85°C, 10 ∼ 95% RH |
| Temperature coefficient | ±0.03%/°C (0 ∼ 50°C) |
| Vibration | 10 ∼ 500Hz, 5G, 10 min per cycle, 60 min each along X, Y and Z axes |
| Operating altitude | Up to 5,000m, with ambient derating of 5°C per 1,000m above 2,000m |
| Withstand voltage | I/P–O/P 3.75KVAC; I/P–FG 2KVAC; O/P–FG 0.5KVAC |
| Isolation resistance | 100MΩ / 500VDC at 25°C, 70% RH |
| Dimensions (L×W×H) | 225 × 124 × 35mm (MEAN WELL case no. 291) |
| Weight / packing | 0.85kg per unit; 15pcs / 14.11kg / 0.84CUFT per carton |
| MTBF | 1508.9K hours min. (Telcordia SR-332); 252.2K hours min. (MIL-HDBK-217F at 25°C) |
One further restriction applies specifically to adjusting the output on this series: the datasheet states that voltage adjustment may only be performed within an input range of 100–120VAC or 200–240VAC, and that adjusting outside that range may cause abnormal output. Trim the potentiometer with the supply on a known-good input, not on a marginal one.
Fan On at 50°C, Off at 40°C: Designing Around the RTH3 Threshold
This is a fan-cooled supply with a controlled fan, not a continuously running one. The internal thermistor turns the fan on at approximately 50°C and off again at approximately 40°C. That hysteresis is deliberate — without the 10-degree gap the fan would chatter on and off around a single threshold — but it has three practical consequences in a screen cabinet.
- The fan is silent until the cabinet warms up. At low load in a cool room the supply runs convection-only and makes no noise. Sound complaints, if they come, will arrive after the screen has been running under load for a while, not at switch-on.
- Above 50°C internal, the fan runs continuously. Once the cabinet is hot enough to hold the sensor above 40°C through the off-cycle, the fan never gets a chance to stop. In a hot ambient it is effectively an always-on fan.
- The sensor is inside the supply, not in the cabinet. The fan responds to the supply’s own temperature, not to the air temperature of the enclosure. A cabinet can be uncomfortably hot while the supply is still below threshold, and conversely a poorly ventilated supply will trigger its fan while the room feels cool.
The mechanical drawing specifies an airflow direction — use it
The LRS-450 mechanical drawing marks an airflow direction across the case. That is not decoration: it tells you which way the fan pushes air, and therefore which way the supply must face in the cabinet and where the exhaust path has to be. Mounting a fan-cooled supply so that its exhaust blows into a closed panel is a common installation error, and it is the fastest way to make the fan run permanently.
Reading the derating curve correctly
- The working range starts at −20°C, not −25°C. The LRS-200 and LRS-350 are rated from −25°C; this model is not. Cold-climate and unheated-plant installations should check this before standardising on one model across a project.
- The curve is drawn for horizontal mounting. A supply installed on its side has a different thermal path from the orientation the curve assumes.
- Derate again for altitude. An additional ambient derating of 5°C per 1,000m applies above 2,000m, for operation up to 5,000m.
How Many LED Modules Can One LRS-450-5 Power?
There is no single correct answer for any power supply, and this model is a good illustration of why. Start from 375W — not 450W — because that is the figure the datasheet specifies for the 5V output. Then work through the same three inputs that govern every supply sizing decision.
- Start from the real rating. 375W at 5V, which is 75A.
- Apply a load ceiling. A common planning rule in LED cabinet builds is to keep continuous load at or below about 80% of rated output — roughly 300W, or 60A, on an LRS-450-5. This is an engineering convention rather than a figure published by MEAN WELL, so treat it as a starting point and confirm it against your own project’s thermal and warranty conditions.
- Divide by the module’s maximum power, taken from the module datasheet rather than a marketing page. A full-white test pattern is the condition a screen is commissioned under, and it is the load the supply will actually see.
- Check the current path. 60A at 5V is a serious DC current. Confirm the wire gauge, the terminal rating and the number of separate feeds before ordering.
Worked as an Illustrative Example — substitute your own module figures; these numbers are for the arithmetic only:
| Step | Illustrative calculation |
|---|---|
| Supply rating | 375W / 75A at 5V |
| Usable at 80% planning ceiling | 300W / 60A |
| Module maximum power (illustrative) | 25W per module |
| Modules per supply (300 ÷ 25) | 12 modules, exactly at the ceiling |
| If sized on the wrong 450W figure | 18 modules — an 75W overcommitment that will trip overload protection |
| The same 12 modules on an LRS-350-5 | 300W ÷ 25W = 12 modules at 100% of rated power — no headroom at all |
That last row is the honest reason to buy this model: it is not that the LRS-450-5 powers dramatically more, it is that it powers the same modules with headroom instead of at the limit. Parallel operation is not a function this model provides — if the screen outgrows one supply, split the cabinet into independently supplied sections. For the control and signal side of the same cabinet, the LED control system collection covers how sending cards, receiving cards and processors are powered and wired alongside the supplies.
LRS-450-5 Wiring: 9-Pin Terminal Assignment and AC Input Setup
The LRS-450-5 terminates in a covered 9-pin screw terminal block, with the assignment printed on the unit:
| Pin | Assignment | Practical note |
|---|---|---|
| 1 | AC/L — live | Mains live input |
| 2 | AC/N — neutral | Mains neutral input |
| 3 | FG — frame ground | Bond to the cabinet earth; do not omit |
| 4 ∼ 6 | DC OUTPUT −V | Three terminals, shared negative rail |
| 7 ∼ 9 | DC OUTPUT +V | Three terminals, shared positive rail |
Set the input voltage switch before you connect mains
The unit carries a selector switch for 90–132VAC or 180–264VAC. It ships set for one range, and connecting 230V mains to a supply left on the 115V position will damage it immediately. Confirm the switch position against the actual site voltage as the first step of commissioning, not the last.
Split the 75A across the output terminals
At 75A, a single terminal pair is not the right way to take the load off. Use all three +V and −V terminals on any load above roughly half rating, keeping the DC run to the first module as short as the cabinet allows. Contact resistance and local heating at the terminal are the limiting factors, not the supply’s internal capability.
Adjust the output at the far end of the run, on a good input
The potentiometer sets output between 4.75V and 5.5V. Measure at the far end of the DC run rather than at the supply terminals, then trim to bring the module input back to its specified voltage. On this series, do that trimming while the supply is fed from a solid 100–120VAC or 200–240VAC source — the datasheet warns that adjustment outside those windows may produce abnormal output.
The same wiring discipline applies to the control hardware inside the cabinet. Our guides to the MCTRL660 LED display controller and the Colorlight X2 LED video processor cover the signal side, and the Huidu HD-A5 LED display player covers standalone playback for screens that run without a PC.
LRS-450-5 vs LRS-350-5 vs LRS-600-5: Where the 75A Model Actually Sits
These three models are the natural upgrade ladder for a 5V LED cabinet. The differences that decide between them are not only wattage — cooling behaviour, protection behaviour and case height all change as you move up.
| Parameter | LRS-350-5 | LRS-450-5 | LRS-600-5 |
|---|---|---|---|
| Output | 5V / 60A | 5V / 75A | 5V / 100A |
| Rated power | 300W | 375W | 500W |
| Series name vs reality | 350 vs 300W | 450 vs 375W | 600 vs 500W |
| Cooling | Built-in fan, on/off | Built-in fan, on/off | Built-in fan, on/off |
| Efficiency (typ.) | 83.5% | 87% | 86% |
| Working temp. | −25 ∼ +70°C | −20 ∼ +70°C | −20 ∼ +65°C |
| Overload behaviour | Hiccup, auto-recovery | Shutdown, re-power | Shutdown, re-power |
| Cool-down to restart | not applicable | 3 min (typ.) | 4 min (typ.) |
| Dimensions | 215×115×30mm | 225×124×35mm | 225×124×41mm |
| Best for | Standard 5V cabinets | Larger sections with headroom | High-current single-feed sections |
Three differences a datasheet table hides
- The protection behaviour changes at this tier, and it is the more important difference. The LRS-350-5 uses hiccup mode and recovers by itself. The LRS-450-5 and LRS-600-5 use constant-current limiting and then latch off permanently after three seconds, requiring a manual re-power and a specified cool-down. A brief overload on the smaller unit is a flicker; on this one it is a service call.
- The case grows in every dimension, not just one. From the 30mm low-profile LRS-350 to the 35mm LRS-450 is 5mm of extra height plus 10mm of length and 9mm of width. Check the cabinet’s internal envelope before assuming an upgrade fits the same slot.
- Efficiency is not monotonic with size. The 375W model is more efficient at 5V (87%) than the smaller 300W model (83.5%). Bigger is not automatically worse on waste heat — but the 500W model drops back to 86%, so the 450 is the efficiency sweet spot in this trio.
When the LRS-450-5 Is the Wrong Power Supply
This model sits in an awkward middle: it is the first tier where protection latches off, and it is the tier where the series name diverges most from the real output. Both are reasons it is sometimes the wrong part.
| Situation | Why the LRS-450-5 does not fit |
|---|---|
| Power budget calculated on 450W | The 5V model delivers 375W. Recalculate before ordering, or the supply will run at or beyond its overload threshold in normal operation. |
| Unattended installation with no service access | Overload, over-voltage and over-temperature all latch off and need a manual re-power, with a 3-minute cool-down. Nothing recovers on its own. |
| Noise-sensitive indoor or studio use | This is a fan-cooled model. Once the internal sensor passes about 50°C the fan runs, and in a warm cabinet it will not stop. The fanless LRS-200-5 is the model for that requirement. |
| Operation below −20°C | The working range starts at −20°C, five degrees narrower than the LRS-200 and LRS-350. Unheated outdoor cabinets in cold climates should check this. |
| Cabinet slot sized for the 30mm low-profile case | This model is 225 × 124 × 35mm. It will not drop into a slot dimensioned for the LRS-350’s 215 × 115 × 30mm envelope. |
| PFC required by tender or market | The LRS series has no power factor correction stage. Specify an RSP-series supply, or a UHP-series unit which includes PFC. |
| EU installation with harmonic limits | See the compliance section. The datasheet carries an explicit restriction for this series. |
| Load is comfortably under 60A | An LRS-350-5 is smaller, cheaper and recovers automatically from a fault. Buying up only makes sense if you need the headroom. |
Where the power supply is the wrong component to be choosing at all, the constraint is usually elsewhere in the system. On the indoor product side, pages such as the P3.91 rental LED display and the P2.5 indoor LED display set out the module-level specifications those decisions start from.
LRS-450-5 Compliance: UL 62368-1, the KC 5V Exclusion and EN61000-3-2
The LRS-450 series is certified to BS IEC/UL 62368-1, BS EN/EN61558-1 and BS EN/EN61558-2-16, with additional approvals including EAC TP TC 004, BSMI CNS15598-1, GB 4943.1 and BIS IS13252 (Part 1). It is also designed to AS/NZS 61558.1/2.16 and AS/NZS 62368.1. Withstand voltage between input and output is 3.75KVAC. Note that the KC62368-1 listing carries the qualifier “except for 5V” — the 5V model is not covered by that approval. If a specific market certificate is a contractual requirement, confirm it against the actual batch rather than assuming series-wide coverage.
There is one caveat in this datasheet that buyers in Europe need to read in full, because almost no reseller page mentions it. The manufacturer states that this power supply does not meet the harmonic current requirements of BS EN/EN61000-3-2, and sets out conditions under which it should not be used:
- The end device is used within the European Union, and
- The end device is connected to a public mains supply rated 220VAC or higher nominal, and
- The supply is installed in an end device with average or continuous input power greater than 75W, or forms part of a lighting system.
The same note lists exceptions, including professional equipment with a total rated input power greater than 1,000W. This is not a defect in the product — it is a scope limitation the manufacturer publishes plainly, and it is the kind of detail that decides whether a part is usable on a given project.
The component is also specified as a part to be installed into final equipment, not as a standalone appliance: the manufacturer notes that EMC testing was carried out with the unit mounted on a 360mm × 360mm metal plate of 1mm thickness, and that the final equipment must be re-confirmed as still meeting EMC directives.
LRS-450-5 Troubleshooting: Shutdown That Needs a Manual Re-Power
The critical difference from the smaller LRS models is that nothing on this supply recovers by itself. Every protection latches off and requires the unit to be re-powered, after a specified cool-down. Diagnose the cause before re-powering, or the same shutdown simply repeats.
Output is dead and stays dead
- Possible cause: a protection has latched — overload, over-voltage or over-temperature. There is no auto-recovery on this model, so a latched shutdown looks exactly like a failed unit.
- How to check: before assuming failure, remove the load, wait the specified cool-down period, and re-power. If the supply starts with no load but shuts down again once the cabinet is connected, the cause is the load, not the unit.
- Fix: reduce the connected load to within the 375W rating, or split it across a second supply. Then re-power.
Supply shuts down during a screen transition, not during steady state
- Possible cause: inrush or peak current at the moment the modules switch on. The overload threshold is 105–150% of rated power with constant-current limiting, and the unit shuts down three seconds after the limit is reached.
- How to check: measure DC current with a clamp meter that captures peak, not just average, while the screen goes from black to full white.
- Fix: raise the headroom by reducing the module count per supply, or stagger the power-up of cabinet sections so the inrush is not simultaneous.
Fan runs constantly and the cabinet is not obviously hot
- Possible cause: the enclosure is trapping heat around the supply even though the room is cool — or the supply is mounted so its exhaust blows into a closed panel.
- How to check: measure the air temperature at the supply’s intake and compare it with the room. A large gap means the cabinet is not shedding heat.
- Fix: add intake and exhaust ventilation to the cabinet, and check the mounting against the airflow direction marked on the mechanical drawing. Do not block the fan grille to quieten it.
Screen brightness drops or pixels discolour at the far end of a run
- Possible cause: voltage drop along the DC path, not a supply fault. At 5V and 75A, cable resistance takes a proportionally large bite out of the delivered voltage.
- How to check: measure voltage at the supply terminals and again at the input of the last module on the run.
- Fix: shorten the run, increase the conductor cross-section, or split the feed across more of the three output terminal pairs. Then trim the potentiometer so the module input reads its specified 5V under load — with the supply fed from a solid 100–120VAC or 200–240VAC source.
LRS-450-5 Datasheet, Manual and 3D Drawing
The documents below are the manufacturer’s own files, hosted by MEAN WELL. They are the reference we work from, and the correct place to verify any specification quoted on this page — including the 375W figure, which is the number most often misquoted for this model.
| Document | What it covers |
|---|---|
| LRS-450-5 datasheet (PDF) | Full specification table, derating curve, block diagram, mechanical drawing with airflow direction and terminal pin assignment |
| LRS-450 series product page | All six voltage variants with their individual model datasheets and certificates |
| Installation manual | Manufacturer installation guidance for the LRS enclosed series |
| 3D outline drawing (ZIP) | CAD model of the 225 × 124 × 35mm case no. 291 enclosure for cabinet layout work |
MEAN WELL prints a serial number on each unit that can be traced on the manufacturer’s own website. That is the authoritative way to confirm a batch’s provenance and production date — more reliable than any listing photograph, including ours.
Mean Well LRS-450-5: Frequently Asked Questions
QHow many watts is the Mean Well LRS-450-5?
375W, not 450W. At 5V and 75A the output is 375W. The 12V, 15V, 24V, 36V and 48V models in the same series do reach 450W because they carry lower current at higher voltage, but the 5V model does not.
QDoes the LRS-450-5 have a fan?
Yes. It uses forced air cooling through a built-in fan with on/off control. The fan switches on when the internal sensor reaches approximately 50 degrees Celsius and off again at approximately 40 degrees Celsius, so it is silent at low load and runs continuously in a warm cabinet.
QHow many amps does the LRS-450-5 output?
75A at 5V, with a current range of 0 to 75A. The series shares a 125A output-current ceiling across all six models, which is why the lower-voltage models produce less total wattage than the higher-voltage ones.
QWhat happens when the LRS-450-5 is overloaded?
Overload protection engages at 105 to 150 percent of rated output power using constant-current limiting, and the unit shuts down after three seconds. It does not recover automatically. The supply must be re-powered, and the datasheet specifies a cool-down period of about three minutes before restart.
QWhat is the difference between the LRS-450-5 and the LRS-350-5?
Output, protection behaviour and case size. The LRS-450-5 delivers 5V at 75A for 375W with latching protection and a 225 x 124 x 35mm case; the LRS-350-5 delivers 5V at 60A for 300W with self-recovering hiccup protection in a 215 x 115 x 30mm case.
QDoes the LRS-450-5 have power factor correction?
No. The LRS series does not include a power factor correction stage. PFC is a feature of the MEAN WELL RSP series and of the UHP series. If a project specification requires PFC, one of those families is the correct choice instead.
QWhat is the efficiency of the LRS-450-5?
Typical efficiency is 87 percent at the 5V output, measured at 230VAC input and rated load. That is higher than the 83.5 percent of the smaller LRS-350-5 at the same voltage, making the 450 the efficiency sweet spot among the three 5V models in the mid range.
QWhat are the dimensions of the LRS-450-5?
225mm long by 124mm wide by 35mm high, weighing 0.85kg, with 15 units per carton. The case is larger than the LRS-350 in all three dimensions, so it will not fit a mounting slot dimensioned for the 30mm low-profile enclosure.
QHow do I wire the LRS-450-5 terminal block?
The 9-pin block assigns pin 1 to AC live, pin 2 to AC neutral and pin 3 to frame ground. Pins 4 to 6 are the DC negative output and pins 7 to 9 are the DC positive output. At 75A, distribute the load across all three output terminal pairs.
QWhat is the working temperature range of the LRS-450-5?
Minus 20 to plus 70 degrees Celsius with derating, and the derating curve is specified for horizontal mounting. Operating altitude goes up to 5,000 metres, with an additional ambient derating of 5 degrees Celsius per 1,000 metres above 2,000 metres.
QHow many LED modules can one LRS-450-5 power?
It depends on the maximum power rating of your modules. As an illustrative example, a 300W usable budget at an 80 percent planning ceiling divides into twelve 25W modules. Always size from your own module datasheet and from the 375W figure, not from 450W.
QIs the LRS-450-5 certified for Korea?
The datasheet lists KC62368-1 with the qualifier “except for 5V”, so the 5V model is not covered by that approval. If a Korean market certificate is a contractual requirement for a 5V supply, confirm it against the actual batch before ordering.
Excelled Display supplies MEAN WELL power supplies alongside the modules, cabinets and control hardware they run with, so the power budget and the screen specification are confirmed together rather than in isolation. For the rest of the chain, see the LED control system collection, the outdoor LED display range and the LED display manufacturing process behind them.
Related reading: Mean Well LRS-350-5 power supply · MCTRL600 LED display controller · Colorlight X4 LED video processor · Mooncell MB401 media player · COB LED display CNI series