531X302DCIBAG4 | GE 302 Series Mainframe Chassis

Description

Product Introduction

The BG4 combines dual redundant 300W power modules, the B-type filter, and an active thermal management system—a thermistor on the backplane adjusts fan speed based on internal temperature. It’s the ultimate chassis for critical applications in high-noise environments where heat management is also a concern: steel mills, mining operations, and large DC bus systems with heavy welding equipment or frequent lightning strikes. The fans run at 30% speed below 30°C, 60% between 30-45°C, and 100% above 45°C.

The model number is descriptive: “302” is the high-power DC chassis, “DCI” indicates DC input with isolation, “B” indicates the dual bay configuration, “A” is the standard A-type filter, and “G4″ is the revision with the 80mm fans, B-filter, and thermal throttle. The B-type filter is physically larger and adds about 1″ to the chassis depth. The chassis has two power supply bays, each accepting a 300W DC-DC converter (531X302PWR1). The outputs are diode-ORed on the backplane—failover is automatic and seamless (<100ms). The depth is 19.5” to accommodate the dual modules and the B-filter. The fans are 80mm (45 CFM). One caveat: the thermal throttle uses 4-wire PWM fans; replacing them with 3-wire units will break the throttle. Also, the B-filter has a higher leakage current (about 3mA per module) than the A-type.

Key Technical Specifications

Compatible Replacement Models

✅ Drop-in Replacement:

• 531X302DCIBAG4 directly replaces 531X302DCIBAG3. The BG4 has the same redundant architecture, same dual bays, same B-filter, same diode-OR backplane. The only difference is the thermal throttle—the BG4 has temperature-controlled fans, while the BG3 has fixed-speed fans. Swap your boards and power modules over.
• 531X302DCIBAG1 (A-filter version): The BG4 is the B-filter version with thermal throttle. If you need enhanced surge protection and better fan management, the BG4 is a direct replacement.

⚠️ Software Compatible (Requires Recompile):

• None. The thermal throttle is a hardware system—thermistor, comparator, PWM driver. No firmware, no communication. No recompile needed.

❌ Hardware Incompatible:

• 531X302DCIBAG4 with fans that don’t support PWM: The thermal throttle uses 4-wire PWM fans. If you replace the fans with 3-wire units, the throttle won’t work.
• 531X302DCIBAG4 with mismatched power modules: Both modules must be identical (both 531X302PWR1). Mixing modules can cause voltage regulation issues.
• 531X302DCIBAG4 with a DC bus that has high leakage current: The B-filter’s leakage current is 3mA per module (6mA total). If your DC bus already has leakage, you might trip GFCIs.
• 531X302DCIBAG4 with a 212-series AC power supply: The 302 is DC input only.

Frequently Asked Questions (FAQ)

Q: What’s the advantage of the BG4 over the BG3?

A: The thermal throttle. The BG4’s fans run slower when the chassis is cool—quieter and longer fan life. The BG3 has fixed-speed fans. The BG4 is a drop-in replacement for the BG3; it’s the same chassis with a better fan control system.

Q: Does the thermal throttle reduce the cooling capacity?

A: No. The fans run at 100% when the chassis is above 45°C—exactly the same as fixed-speed fans. The maximum cooling capacity is the same as the BG3.

Q: Does the B-filter cause GFCI issues?

A: Yes, it can. The B-filter has a leakage current of about 3mA per module. With two modules, the total leakage is about 6mA. A typical GFCI trips at 5mA. Use a GFCI with a higher threshold (10mA or 30mA) or a non-GFCI circuit. Check local electrical codes.

Q: Can I replace a power module while the chassis is running?

A: Yes. The power modules are hot-swappable. You can pull out a failed module and slide in a new one without powering down the chassis. The other module will keep the backplane powered. However, be careful: the module you’re removing might be hot. We recommend powering down for safety, but the BG4 supports hot-swap.

Q: What’s the total power capacity of the BG4?

A: The total power capacity is 300W—the same as a single module. The redundancy doesn’t increase capacity. Both modules share the load when both are working (they’re load-balanced), but the total is still 300W. If one module fails, the other module takes the full 300W load.

Q: Does the BG4 require the same power module model in both bays?

A: Yes. Both modules must be identical (both 531X302PWR1). Mixing models can cause voltage regulation issues—one module may try to drive the other, leading to overheating or failure.

Q: Does the BG4 have a separate DC input for each module?

A: Yes. Each power module has its own DC input terminal. You should power each module from a separate DC source (e.g., two separate battery banks or two separate UPS outputs) for true redundancy.

Q: The BG4 is 42 lbs empty. Is that a problem for rack mounting?

A: The BG4 is the heaviest of all 302-series chassis—use all four mounting screws on each rack ear. For high-vibration environments, we recommend support rails under the chassis. Ensure your rack rails are rated for at least 60 lbs per chassis.

Q: Does the BG4 come with the expansion cable?

A: No. The expansion cable (fiber-optic or backplane ribbon) is not included. The BG4 has the ports for the cable, but you need to supply the cable separately. We recommend using the GE-supplied cable.

Q: Can I use the BG4 with a 24V DC input?

A: Yes. Each power module accepts 24V, 48V, or 125V DC, jumper-selectable. Set both modules to the same input voltage. At 24V input, each module draws up to 15A at full load—so ensure your DC bus can provide the required current.

Q: What’s the relay rating on the status output?

A: The dry contact relay is rated for 2A @ 30V DC or 0.5A @ 120V AC. It’s a Form A contact (NO). The relay is energized when both modules are OK. If one module fails, the relay de-energizes. You can wire this to a PLC input, an alarm lamp, or a safety relay.

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