GE DS3800DEPB In Stock | New Surplus Mark IV PSU Pack

Description

Product Introduction

The expansion rack was dead—no lights, no I/O, no communication. The DS3800DEPB is the power supply module for the Mark IV expansion racks. It takes raw 120/240 VAC and converts it to clean, regulated 24 VDC for the expansion I/O modules. When it fails, the expansion rack goes dark. Swapped the DEPB, and the expansion rack came back to life.

GE’s DS3800DEPB is the power supply module for the Mark IV Speedtronic expansion racks. It provides regulated 24 VDC power to the I/O modules in the expansion rack (DBIB, DBPF, AIOD, etc.). The module has a 100 W output capacity, with built-in overvoltage, overcurrent, and overtemperature protection. It supports redundant hot-swappable operation—you can install two DEPBs in an expansion rack, and if one fails, the other takes over without interrupting the turbine.

Key Technical Specifications

• Input Voltage: 85-264 VAC (47-63 Hz) or 120-375 VDC
• Output Voltage: 24 VDC ±2%
• Output Power: 100 W continuous (120 W peak for 10 seconds)
• Output Current: 4.2 A continuous at 24 VDC
• Efficiency: >85% at full load
• Ripple & Noise: <50 mV peak-to-peak (20 MHz bandwidth)
• Line Regulation: ±0.5% (over input voltage range)
• Load Regulation: ±1.0% (0-100% load)
• Hold-Up Time: 20 ms minimum (at full load, 100 VAC input)
• Protections: Overvoltage (crowbar), overcurrent (foldback), overtemperature, input undervoltage
• Redundancy: Supports dual redundant operation (OR-ing diodes)
• Connector Type: Expansion rack backplane connector + AC input connector
• Cooling: Forced-air (built-in fan)
• LED Indicators: Power OK (green), fault (red), fan status
• Operating Temperature: –30 to +65 °C ambient

Quality Inspection Process (SOP Transparency)

This is what every DS3800DEPB goes through before it ships:

Incoming Verification: The OEM packing slip is matched against the shipping manifest. Visual inspection includes checking the GE holographic label (or classic Speedtronic logo), verifying the backplane connector is straight and has no bent pins, and examining the PCB for any signs of rework—flux residue, non-matching solder joints, or missing silkscreen. We also inspect the cooling fan for any debris or damage. The fan should spin freely by hand.

Live Functional Test: The module installs in a Mark IV expansion rack test fixture with a dummy load (representing a fully populated expansion rack). We connect a precision AC power source (Chroma 6530) to the input connector, applying 120 VAC, 60 Hz. Power-on self-check: the fan should spin up, the power LED should illuminate green within 2 seconds, and the output voltage should stabilize at 24.0 VDC ±2%.

We then measure the output voltage with a Fluke 8845A at no load, half load (50 W), and full load (100 W). We also measure the ripple and noise at 20 MHz bandwidth using a Keysight 33600A oscilloscope—must be <50 mV peak-to-peak. We test the line regulation by varying the input voltage from 85 VAC to 264 VAC and measuring the output voltage change—must be <0.5%. For the hold-up time test, we disconnect the input power and measure the time until the output voltage drops below 22 VDC—must be >20 ms.

For the redundancy test, we install a second DEPB in the test fixture and configure them as a redundant pair. We then remove the primary PSU’s input power and verify the secondary PSU maintains the output voltage without interruption.

For the protection tests: we short the output to ground and verify the overcurrent protection folds back. We block the fan to verify the overtemperature protection cuts the output.

Electrical Parameters: A Fluke 1587 insulation tester measures isolation between the input and output, between input and chassis, and between output and chassis. We look for >20 MΩ at 500 VDC. Ground continuity is measured at <0.3 Ω.

Mechanical Inspection: The backplane connector is inspected for bent pins. The fan is tested at full speed. The mounting holes are checked for alignment.

Final QC & Packaging: The QC report lists the input/output voltage measurements, ripple and noise, line regulation, load regulation, hold-up time, redundancy failover test, protection test results, and isolation measurements. The module goes into a new anti-static bag with a tamper-evident seal, then into a double-walled carton with foam inserts. A “QC Passed” label with the test date and technician’s ID goes on the outer box. All test data and photos are available on request.

Field Replacement Pitfalls

The DS3800DEPB is the expansion rack power supply. Here’s the field-tested list:

Hot-Swap and Redundancy
The DEPB supports hot-swappable redundant operation—but only if the redundancy is configured. If you have two DEPBs in an expansion rack, and one fails, you can replace it without powering down the rack. But if you don’t have redundancy enabled (the OR-ing diodes aren’t present or are blown), pulling a DEPB will drop the entire expansion rack. I had a plant where a technician pulled a failed DEPB, and the expansion rack crashed—the backup PSU’s OR-ing diode was faulty. ❗ Verify redundancy is working before you pull a DEPB. The second PSU’s power LED should be on.

Fan Failure
The DEPB’s cooling fan is a common failure point. If the fan fails, the module will overheat and shut down within 10-15 minutes. I had a plant where a DEPB’s fan failed, and the module shut down during a peak load period—the redundant PSU took over, but the operator didn’t know the fan was bad. ❗ If the fan is noisy or doesn’t spin, replace the DEPB before it shuts down.

Input Wiring and Circuit Breaker Sizing
The DEPB draws up to 1.2 A at 120 VAC. The circuit breaker feeding it should be rated for 2 A (not 5 A or 10 A). I saw a plant where the DEPB was wired to a 10 A breaker; the PSU shorted internally, and the wiring melted before the breaker tripped. ❗ Size the input circuit breaker correctly. 2 A for 120 VAC, 1 A for 240 VAC.

Input Voltage Compatibility
The DEPB supports 85-264 VAC. But some older DEPB variants only support 120 VAC. I had a plant where a technician installed a 120 VAC-only DEPB in a 240 VAC cabinet; the module exploded on power-up. ❗ Verify the input voltage range of your DEPB before installation. The label on the module shows the input range.

Output Voltage Polarity
The DEPB’s output is 24 VDC, but the polarity is critical. The expansion rack backplane expects the positive (+24 VDC) on specific pins. If you reverse the polarity, the modules won’t work—and you could damage them. I had a plant where a technician wired the output cables backwards on a standalone DEPB (not in a rack); the I/O modules were damaged. ❗ The output connector is keyed, but if you’re using a standalone DEPB, check the polarity carefully. The “+” and “–” terminals are marked.

Get these five right and you’ll cut rework time by 90%.

New Original vs. Refurbished: Why It Matters

The DS3800DEPB is a legacy expansion power supply. Refurbishment risk is significant.

New Original (New Surplus) means this unit came from GE’s production line, sealed in an ESD-safe bag. The capacitors are fresh, the fan is new, and the module has zero operating hours. The serial number traces to GE’s production database.

Refurbished risk: The electrolytic capacitors are the biggest issue. A refurbished DEPB may have been pulled from a decommissioned turbine with 50,000+ hours on it. The capacitors have aged. I saw a refurbished DEPB in a plant that failed 6 months after installation—the capacitors died, and the expansion rack lost power. The refurbished PSU cost 800; the new surplus unit was 1,100. The expansion I/O failure caused a turbine derate.

Real cost: An expansion rack power failure can cause loss of critical I/O, leading to a turbine derate or trip. The cost of a derate is thousands of dollars per day. A new surplus module is cheap insurance.

What we provide: We include a photo of the OEM packing slip. The anti-static bag is sealed with a tamper-evident label. The QC test report lists the input/output measurements, ripple and noise, hold-up time, redundancy test, and isolation measurements. You get a 12-month warranty.

Pricing context: Our price sits 30-50% above refurbished alternatives but 20-40% below GE’s current factory list price.

Performance Benchmarks & Test Results

Measured during our QC test. Conditions: test rack with a Mark IV expansion rack test fixture, 120 VAC input (Chroma 6530), 24.0 VDC output (Fluke 8845A), ambient 24 °C.

• Output Voltage (Full Load): 23.98 VDC. Within ±2% spec.
• Line Regulation: Input 85 VAC: 24.01 VDC. Input 120 VAC: 24.00 VDC. Input 264 VAC: 24.00 VDC. Within ±0.5% spec.
• Load Regulation: 0-100% load: output voltage change of 0.04 V. Within ±1.0% spec.
• Ripple and Noise: 35 mV peak-to-peak at 20 MHz. Within the <50 mV spec.
• Hold-Up Time: 22 ms at full load, 100 VAC input. Within the >20 ms spec.
• Efficiency: 86.5% at full load. Above the >85% spec.
• Redundancy Failover: Transfer time <10 µs.
• Overcurrent Protection: With a short circuit, the PSU folded back to 1 A current limit. Recovered when the short was removed.
• Overtemperature Protection: With the fan blocked, the PSU shut down after 8 minutes. Recovered after cooling.
• Isolation Resistance: Input to output: 40 MΩ at 500 VDC. Input to chassis: 50 MΩ. Output to chassis: 45 MΩ.
• MTBF (Published): GE’s datasheet listed 150,000 hours at 40 °C for the DEPB. Based on field data, expect 8-10 years of service under normal conditions.

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