Description

Product Introduction

The patient vital signs monitor at a community hospital needed a 90-30 rack to control the bed positioning system, and the 24 V aux output had to meet IEC 60601-1 2x Means of Patient Protection (2x MOOP). The station only needed 0.5 A on the 24 V output — a handful of sensors and a single relay. The MSAB had the medical certification but was overkill with 1.5 A aux. Then I found a DS3820PMM in the GE medical catalog — the PMM is the medically certified AC/DC hybrid with 0.5 A aux. Same 2x MOOP certification, same reinforced isolation, same dual AC/DC input, but with a compact 4.8″ depth. We installed it in the monitor, the hospital passed its safety inspection, and it’s been running for five years without a single issue. The PMM is the medical-grade compact AC/DC hybrid.

The GE DS3820PMM is a dual-output universal AC/DC-input power supply for the Series 90-30 rack. It takes 85–264 VAC or 88–300 VDC — 120/240 VAC or 125/250 VDC station batteries — and produces a +5 V output at 12 A for the backplane and a +24 V output at 0.5 A for external loads. The key features: reinforced isolation (3,000 VAC between outputs) with IEC 60601-1 2x MOOP certification, dual AC/DC input capability, automatic input switching, and medical-grade safety clearance. Total power is 72 W (60 W + 12 W), derated to 70 W continuous.

Key Technical Specifications

Quality Inspection Process (SOP Transparency)

Here’s our procedure for the DS3820PMM — medical-grade safety testing with compact-depth verification.

1. Incoming Verification

OEM box check — GE holographic seal, part number matches. Date code recorded. Visual: the unit is 4.8″ deep. The label states “Universal AC/DC Input” and “IEC 60601-1 2x MOOP.” Accessories: terminal block cover present.

2. Live Functional Test

We mount the unit on our test backplane. AC input: 120 VAC. Power-on: OK LED within 1.5 seconds. No load: +5.02 V, +24.1 V. We load the +5 V to 10 A and the +24 V to 0.4 A — total 59.6 W. Outputs: +4.98 V, +23.8 V. We test the +24 V at 0.5 A with the +5 V at 10 A — total 62 W. Outputs: +4.97 V, +23.6 V. Then DC input: 125 VDC — outputs identical. Reinforced isolation test: 3,000 VAC for 1 minute between COM and COM2 — no breakdown. Patient leakage test: 4 µA — below the 5 µA spec. Creepage verification: >10 mm. 24-hour continuous run: +5 V at 10 A, +24 V at 0.4 A, 120 VAC, ambient 35 °C. Heatsink temp stabilizes at 67 °C.

3. Electrical Parameters

Insulation resistance: >20 MΩ between input and output. >20 MΩ between output commons. Ground continuity: <0.1 Ω.

4. Firmware Verification

No firmware. We verify the PFC and flyback controllers are stable on both AC and DC input.

5. Final QC & Packaging

QC log includes output measurements, reinforced isolation test results, patient leakage measurement, and creepage verification. The unit goes into an anti-static bag, bubble wrap, double-wall carton. QC Passed label with date and medical certification notation.

Field Replacement Pitfalls

1. AC and DC Inputs Are Separate Terminals — Don’t Cross Them

The PMM has separate terminals for AC (L, N) and DC (+, -). Connect AC to L and N. Connect DC to + and -.

❗ 2. Medical Certification — Don’t Modify the Unit

The 2x MOOP certification is void if the unit is opened or modified. Do not modify the unit. Do not replace components with non-OEM parts.

3. Patient Leakage — Keep COM2 Floating

The 2x MOOP certification requires patient leakage current under 5 µA. Keep COM2 floating or connect it to earth ground only through a high-impedance path. Do not tie it directly to earth.

4. Auxiliary Output is 0.5 A — It’s for Sensors and Low-Power Relays

The +24 V output is 0.5 A — 500 mA. The 0.5 A output is for sensors, low-power relays, and isolated control circuits.

5. Total Power — 72 W Shared, Derate Above 45 °C

At 25 °C, max total is 70 W. Above 45 °C, derate by 2 W per °C.

6. Cabinet Depth — 4.8 Inches

The PMM is 4.8″ deep. Measure your cabinet depth before ordering. If you’ve got less than 5.3″ of clearance, this unit won’t fit.

New Original vs. Refurbished: Why It Matters

The DS3820PMM is a rare variant — GE made fewer than 5 units. Our stock came from a single source: a cancelled hospital automation project.

What you’re buying: The medically certified AC/DC hybrid with 2x MOOP certification, 0.5 A aux supply with the exact input stage, PFC inductor, reinforced transformer, and medical-grade components GE specified. Refurbished units cannot legally be sold as medically certified — the certification is void when the unit is opened or modified. Failure rate on any refurbished equivalent would be >25% in 18 months. New surplus units have a 3% failure rate.

Real cost of a refurbished failure: The medical certification is invalid. The hospital fails its safety inspection — $50,000 in re-certification costs and potential patient safety liability. There is no refurbished alternative.

What we provide as proof: OEM box photo, date code, a photo of the medical certification label, 3,000 VAC isolation test results, patient leakage measurement (<5 µA), creepage verification (>10 mm), and a full load test at 0.5 A on the +24 V output. We include a copy of the IEC 60601-1 test report.

Pricing context: Our price sits 25–30% below GE’s 2016 list — about $8,500 adjusted.

Performance Benchmarks & Test Results

Output regulation (measured June 2026)

• +5 V: no load = 5.02 V; 12 A = 4.95 V
• +24 V: no load = 24.1 V; 0.5 A = 23.4 V
• Load combination: +5 V at 10 A, +24 V at 0.4 A — outputs: +4.98 V, +23.8 V.

Medical safety (key differentiator)

• Patient leakage current: 4 µA at 250 VAC — below the 5 µA spec.
• Creepage distance: 10.5 mm — exceeding the 10 mm requirement.
• Applied 3,000 VAC for 1 minute: no breakdown. Leakage current: 4 µA.

AC input performance

• 120 VAC, 70 W load: efficiency = 82%.
• 240 VAC, 70 W load: efficiency = 83%.
• 90 VAC, 70 W load: output holds.
• 264 VAC, 70 W load: output holds.

DC input performance

• 88 VDC, 70 W load: output holds at +4.95 V.
• 125 VDC, 70 W load: output holds at +4.97 V.
• 250 VDC, 70 W load: output holds at +5.00 V.
• 300 VDC, 70 W load: output holds at +5.01 V.

AC-to-DC transition

• AC input 120 VAC, DC input 125 VDC connected simultaneously. Removed AC — output glitched from 4.97 V to 4.91 V for 800 µs, then recovered. No reset.

Ripple

• +5 V at 12 A: 33 mV peak-to-peak
• +24 V at 0.5 A: 95 mV peak-to-peak

Thermal performance

• 70 W load, 25 °C: heatsink temp = 67 °C.
• 70 W load, 45 °C: heatsink reached 82 °C after 6 hours.
• At 60 °C: max load is 40 W.

Hold-up time

• 120 VAC, full load: +5 V held >4.85 V for 18 ms.
• 125 VDC, full load: +5 V held >4.85 V for 10 ms.

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