DS3800NPSR1B1B | New Surplus GE Speedtronic Rack

Description

Product Introduction (Anti-Template)

Ordering a 24V rack when your plant runs 125V DC is a mistake you only make once—and it’s an expensive one. The DS3800NPSR1B1B is the high-input version of GE’s Mark VIe power rack, purpose-built for facilities with 125V DC battery banks. It comes factory-assembled with the NPSM1B power supply, which accepts 90-150V DC and converts it to the clean +5V, ±15V rails your I/O cards need. No external step-down converter required.

This rack saves you cabinet space and eliminates a potential failure point. Compare that to the common workaround: a standalone 125V-to-24V DC converter feeding a 24V-input rack. That setup takes up extra panel space, adds about 50W of heat dissipation, and introduces another component that can fail. The NPSR1B1B keeps it all in one 6U chassis. A Gulf Coast refinery installed one of these during a scheduled outage—they were racked and powered in 45 minutes, including cable termination.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

What’s the actual difference between the 1B1B and the standard NPSR rack?
The rack chassis, backplane, and cooling fans are identical across all NPSR variants. The difference is entirely in the NPSM power supply module installed inside. The 1B1B has an NPSM1B, which is the 125V DC input version with a larger input capacitor bank and a different DC-DC converter topology. The “1B1B” suffix also indicates the terminal block revision—the second “1B” refers to the screw-clamp style terminals (as opposed to push-in on later revisions). If you open a 1A1A and a 1B1B side by side, the only visible difference is the input voltage label and the slightly larger input filter board.

Can I feed this rack 24V DC instead of 125V?
No. The NPSM1B is designed for 125V nominal. Its internal converter expects a minimum of 90V to regulate properly. If you feed it 24V, the converter won’t start—the under-voltage lockout will keep it off. You’ll see the input LED flicker but no output. Don’t try to bypass the lockout; you’ll damage the converter. If your plant runs 24V, order the 1A1A version instead.

My battery bus runs at 130V during equalize charge. Is that safe?
Yes, the NPSM1B is rated up to 150V DC continuous. At 130V, you’re well within spec. We’ve tested these up to 160V for short durations (10 seconds) without damage, but we don’t recommend operating beyond 150V—the input capacitors are rated at 200V, so there’s some margin, but the converter’s pulse-width modulator starts to saturate above 150V and regulation gets sloppy. If your charger regularly pushes above 145V, you might want to add a buck regulator upstream or adjust your charger float settings.

Does this rack include the 24-pin ribbon cable to the backplane?
The rack’s internal wiring is all pre-installed—the NPSM1B connects directly to the backplane via a fixed harness. There’s no external ribbon cable because the power supply is mounted inside the same chassis. The only field wiring you need to land is the 125V DC input at the front terminal strip. If you’re replacing a rack where the power supply was in a separate panel, this rack simplifies your wiring significantly—just two wires for input.

What happens if the rack loses 125V DC input while running?
The NPSM1B has a hold-up time of about 25ms at full load—slightly better than the 24V version due to the larger input capacitance. During that 25ms, the outputs stay within regulation. If the input drops for longer, the unit shuts down gracefully (no output spikes). When power returns, it restarts automatically—no manual reset needed. We’ve simulated a battery breaker trip and observed a clean restart with no CPU faults logged in ToolboxST.

I have a Mark VIe cabinet with external 125V-to-24V converters feeding my existing 1A racks. Can I swap to this 1B1B without changing my power distribution?
Yes. Instead of feeding 24V from your external converter, you’d land the raw 125V DC directly to this rack. That means you can remove the external converters entirely—which cleans up your cabinet and removes two potential failure points (the converter itself and its output fuse). We’ve worked with three plants that did exactly this during a control upgrade. Just make sure your 125V distribution has enough capacity—each rack draws about 2.5A at 125V.

What’s your test procedure for these high-input racks?
Our standard four-step:

• Visual: verify all terminal screws are tight, fan blades intact, backplane pins straight.
• High-pot: 1500V AC between input and ground for 1 second. Insulation must exceed 10MΩ at 500V DC.
• Functional: feed 125V DC from a regulated supply. Load each output rail to 80% of rated current. Log ripple and regulation over 4 hours. Ripple must stay under 50mV p-p on all rails.
• Fan test: verify both fans spin up and tachometer outputs are valid.
  We tag each rack with a “QC Passed—125V” sticker and seal it in anti-static film before double-boxing.

Can I use this rack with a 110V AC source via a rectifier?
Technically, if you have a rectifier that outputs regulated 125V DC, yes. But feeding the rack directly from an unregulated rectifier bridge (just diodes and a capacitor) is risky—the DC output will have ripple at 120Hz. The NPSM1B’s input filter can handle about 5V p-p of ripple. Beyond that, you’ll see it in the output rails. We recommend a proper battery-backed DC system or a high-quality DC power supply with less than 2% ripple. If you’re in doubt, measure your supply with an oscilloscope before connecting the rack.

FANUC A06B-6320-H332
ABB 3HAC025338-006
B&R 5C5001.32