GE DS3800HRDB MKIV, Relay Driver Card

The GE DS3800HRDB is a specialized Relay Driver Card used in the GE Speedtronic Mark IV series of turbine control systems. It is a legacy part, no longer in production, and is primarily found on the surplus and refurbished markets for the maintenance of older systems. 💡

Function and Purpose

The primary function of the DS3800HRDB is to act as an interface between the low-power digital logic of the Mark IV control system and the higher-power devices it controls, such as relays. Its key roles include:

• Low-Side Switching: The card controls up to 64 external relays by “sinking” current, which means it controls the ground side of the circuit while the positive voltage remains fixed. This method is common in industrial applications because it simplifies wiring and enhances reliability.
• Relay Activation: It enables relays by connecting one terminal to a voltage source and the other to an output channel.
• Current Handling: Each output channel is capable of sinking up to 1 A of continuous current, making it suitable for handling multiple relays and inductive loads.
• Protection Features: The board includes built-in safeguards to prevent damage from overcurrent, thermal overload, and overvoltage. It can safely operate when exposed to voltages up to 30 V and can manage inductive load spikes up to 80 V.
• Isolation Barrier: It features an isolation barrier that prevents current from flowing back into the PCI slot, protecting the motherboard and connected systems from electrical interference.

Technical and Design Features

The DS3800HRDB is a robust, industrial-grade circuit board designed to operate in a demanding environment.

• Legacy Part: The “DS3800” prefix indicates that it belongs to the legacy Mark IV series, a pioneering control system for gas and steam turbines.
• Connectors: The board has a large female port and two male terminals with blue covers and clips for secure connection.
• EPROMs and EEPROMs: The card contains a mix of 22 EPROMs and EEPROMs. The EPROMs hold the programming that can be changed, while the EEPROMs are fixed.
• Components: It is populated with a variety of components, including capacitors, resistors, transistors, and diodes.