GE DS3800HDRC1A1A

Technical Specifications

• Product Type: High-Density Relay Control Board (Revision 1A1A)

• Part Number: DS3800HDRC1A1A

• Manufacturer: General Electric (GE)

• System Compatibility: GE Speedtronic Mark IV Turbine Control Systems

• Output Channels: 32 relay outputs – highest density in Mark IV relay family

• Contact Type: Form C (SPDT) per channel

• Contact Rating: 5A @ 250VAC or 5A @ 30VDC (resistive); 2A @ 250VAC (inductive)

• Coil Voltage: 24Vdc (from backplane)

• Latching Capability: Magnetic latching relays (maintain state after power loss)

• Surge Suppression: Built-in RC snubbers and flyback diodes per channel

• Indicators: Front-panel LEDs per channel + mechanical flag indicators (latching)

• Protection: Coil over-current protection

• Isolation: 1500Vrms opto-isolation (logic-to-field)

• Temperature Range: 0°C to +60°C

• MTBF: > 120,000 hours (MIL-HDBK-217F)

Key Features & Advantages

• Latching Relays: The GE DS3800HDRC1A1A uses magnetic latching relays that maintain their state after power loss, critical for trip circuits and safety interlocks.

• Mechanical Flag Indicators: Provide instant visual confirmation of relay status without tools.

• Highest Relay Density: 32 channels on a single 6U board maximizes rack space efficiency.

• Built-In Surge Suppression: RC snubbers + flyback diodes protect contacts and logic from inductive load spikes.

• Proven Reliability: Initial revision with long field track record.

• Diagnostic LEDs: Front-panel LEDs indicate output status per channel.

Typical Application Cases

• Critical Trip Circuits: Provides latching outputs for emergency shutdown valves, maintaining trip state after power loss.

• Safety Interlocks: Provides latching relay contacts for safety permissives and interlocks.

• Alarm Annunciation with Memory: Provides alarms that remain visually indicated even after power cycles.

• Space-Constrained Installations: Maximizes I/O density where rack space is limited.

Competitive Comparison

The GE DS3800HDRC1A1A is functionally identical to the base DS3800HDRC and uniquely combines 32 channels, latching relays, mechanical flags, and Form C contacts in a single high-density board.

Selection Guidelines & Precautions

1. Latching Relay Reset: After a trip, latching relays must be reset via command from the Mark IV processor or manual reset. The GE DS3800HDRC1A1A retains state until reset.

2. Contact Rating: Ensure load current does not exceed 5A resistive or 2A inductive per channel.

3. Inductive Loads: Use external suppression for loads exceeding the built-in RC snubber capability.

4. Flag Maintenance: Mechanical flags can stick after prolonged idle periods. Cycle each channel during commissioning to ensure free movement.

5. Wiring: Use appropriate gauge wiring for current loads.

6. ESD Handling: Use ESD-safe practices.

7. Sourcing: Obsolete. Request functional test report including all 32 channels tested.

8. Spare Strategy: Keep one spare GE DS3800HDRC1A1A on-site for critical latching relay applications. If higher isolation or extended temperature range is required, consider later revisions.