Mean Well Power Supply FAQ: SDR-240-48, LRS-350-24, UPS, 7.1 Audio, and Flip Phones

I've been the office administrator for a 120-person company since 2020. I manage facilities and IT purchasing—roughly $180k annually across 12 vendors. I report to operations and finance. I'm not an electrical engineer. I'm the person who has to make sure the label printer doesn't go down, the AV rack stays on, and finance doesn't reject the invoice. When people ask me about Mean Well—often typed as meanwell—power supplies, UPS backup, 7.1 audio, or even how to turn on flip phone, I answer from the purchasing side.

Here are the questions I get most often. I've split them into short answers, because that's how I wish vendor pages worked. I process about 70-90 orders a year, give or take.

• What's the difference between Mean Well SDR-240-48 and LRS-350-24 power supply?
• Can I run a Mean Well power supply on a UPS?
• What does 7.1 mean for power load?
• DIN rail vs enclosed: which Mean Well should I buy?
• What should I verify before ordering Mean Well?
• How to turn on flip phone?
• When should I not use Mean Well?

What's the difference between Mean Well SDR-240-48 and LRS-350-24 power supply?

The short answer: mounting and output. The Mean Well SDR-240-48 (meanwell sdr-240-48) is a 240W DIN rail supply with 48V output at 5A. The Mean Well LRS-350-24 power supply (meanwell lrs-350-24 power supply) is a 350W enclosed supply with 24V output at about 14.6A. I've bought both. The SDR-240-48 goes in control cabinets where tidiness matters. The LRS-350-24 goes in machines, test benches, and AV racks where you need more wattage and 24V.

I went back and forth between them for a conveyor project in 2024. The SDR-240-48 offered clean DIN rail mounting and 48V for sensors. The LRS-350-24 offered 350W and lower cost per watt. Ultimately I chose the LRS-350-24 because our motors and relays were 24V. But if your panel is DIN rail and your devices need 48V, the SDR-240-48 is the one. Check derating: above 50°C ambient, you may lose capacity. I learned that after a cabinet got hot—well, hotter than our HVAC plan assumed. Everything I'd read said buy the biggest wattage you can afford. In practice, over-sizing without checking derating can just mean a bigger cabinet and more heat.

Can I run a Mean Well power supply on a UPS (often typed as ups)?

Yes, usually. A Mean Well AC/DC supply can plug into a UPS AC outlet. That's common for label printers, small servers, and access control. But a power supply is not a UPS. If you need backup, the UPS should be on the AC input, or you need a DC-UPS module and battery for 24V or 48V DC backup. I'm not an electrician, so I verify with our controls vendor before signing off.

The tricky part is sizing. Don't assume a 350W supply needs only a 350VA UPS. Inrush current and startup spikes can trip a small UPS. For one LRS-350-24, we used a 1500VA UPS on the AC side. For a 24V control circuit, we used a Mean Well battery charger plus a sealed battery. Check the datasheet and the relevant safety standard, like IEC/EN 62368-1, before you assume anything.

What does 7.1 mean for power load?

In AV, 7.1 means seven surround channels plus one subwoofer. For power, it's just a load number. A 7.1 receiver and amplifiers can pull hundreds of watts—sometimes over 1,000W if you drive large speakers hard. If you're powering a 7.1 rack, add up continuous wattage, not peak. A single LRS-350-24 might be fine for one device, but it won't run the whole rack.

This worked for us in a small conference room, but our situation was a 7.1 system with low continuous draw. If you're driving large speakers at high volume, the calculus might be different. Also, 7.1 can mean a software version, so context matters. I once had a ticket that said 7.1 down and it was a software release, not audio.

DIN rail vs enclosed: which Mean Well should I buy?

DIN rail, like the SDR series, is for control panels, PLCs, building automation, and any cabinet where you want clean wire routing. Enclosed, like the LRS series, is for equipment, LED lighting, industrial machines, and AV racks. DIN rail is easier to swap. Enclosed is often cheaper per watt and has terminal covers.

I'd rather work with a specialist who knows their limits than a generalist who overpromises. Mean Well is a power supply specialist. That's why I buy their supplies. But if you need a full UPS with runtime software, network card, and battery health reporting, that's not their lane. A good supplier will tell you what they don't do. That earns trust for everything else.

What should I verify before ordering Mean Well?

Voltage, current, wattage, mounting, derating, certifications, and invoice capability. I once found a great price from a new vendor—$40 cheaper per unit. No, wait—$45 once shipping was included. Ordered 20 units. They couldn't provide a proper invoice, only a handwritten receipt. Finance rejected the expense report. I ate $2,400 out of the department budget. Now I verify invoicing capability before placing any order.

Also buy from authorized distributors. Mean Well is widely copied, and a fake supply can fail in ways that cost more than the unit. Check IEC/EN 62368-1 for safety, UL 508 if it's going into an industrial control panel, and EN 60715 for DIN rail compatibility. If the price is too good, ask why.

"Total cost of ownership includes unit price, DIN rail kit, wiring, UPS batteries, replacement labor, and downtime. The lowest quoted price often isn't the lowest total cost."

How to turn on flip phone

Press and hold the End/Power button—usually the red button—for 2-3 seconds. If it doesn't turn on, charge it for 30 minutes and try again. That's it. The literal search was how to turn on flip phone. A new hire asked me this last week. Not a power supply issue, but office admin life includes everything.

When should I not use Mean Well?

When you need a full UPS with battery monitoring, network management, and software. When you need custom 7.1 audio processing. When you need a one-off 5W supply and shipping costs more than the unit. When you need same-day local repair.

I can only speak to our context: a 120-person company with predictable ordering and three locations. If you're a seasonal business with demand spikes, or you need mission-critical 24/7 uptime, the calculus might be different. Mean Well is great at power conversion. But a specialty vendor for UPS or AV may be better for the full solution. That's not a weakness. It's professional boundaries.

Final note on UPS and Mean Well LRS-350-24 power supply

If you're pairing a UPS with a Mean Well LRS-350-24 power supply, size the UPS for inrush, not just steady-state watts. I went back and forth on a 1000VA vs 1500VA unit for two weeks. The 1000VA was cheaper. The 1500VA gave headroom. I chose the 1500VA because a failed print job during a client deadline would cost more than the price difference. Even after choosing it, I kept second-guessing. What if it was overkill? The two weeks until installation were stressful. It worked fine. But your mileage may vary.