Description

GE Multilin 750 SR750 Feeder Management System

The GE Multilin 750 (SR750), also cataloged as the SR750 Feeder Management System, operates as a dedicated hardware component for feeder protection, measurement, and control execution within electrical distribution protection networks. The unit provides digital processing of current, voltage, status inputs, and control outputs through a drawout relay platform.

Hardware Specifications

Parameter	Specification
Model	750 / SR750
Brand	GE Multilin (General Electric)
Operating Temp	-40 deg C to +60 deg C
Series	700 Series Feeder Management System
Control Power Supply	HI Option: 88-300 VDC or 70-265 VAC; LO Option: 20-60 VDC or 20-48 VAC
CT Inputs	1 A or 5 A phase CT inputs; 1 A or 5 A ground CT inputs
VT Inputs	50 V to 240 V secondary inputs
Digital Inputs	Up to 12 programmable contact inputs
Output Relays	Up to 8 programmable output relays
Analog I/O	Optional 4-20 mA transducer inputs and outputs
Communications	RS232 front port, dual RS485 rear ports with Modbus RTU, optional Ethernet Modbus TCP

Industrial Control Communication and Firmware Compatibility

The GE Multilin 750 integrates programmable processing functions for feeder protection, metering, and control logic. The relay supports configurable I/O mapping, communication interfaces, and firmware-managed operating functions within the 700 Series platform. Communication architecture includes serial Modbus RTU connectivity through RS485 ports and optional Ethernet Modbus TCP integration for supervisory systems.

Firmware flash compatibility is managed according to the relay hardware configuration and installed option set. Firmware updates require verification of hardware revision, communication configuration, and application settings before deployment.

Frequently Asked Questions

Q: Does the SR750 support hot-swap replacement during energized operation?

A: The SR750 uses a drawout case design. Removal and insertion procedures must follow site electrical isolation requirements and the applicable protection system maintenance procedures.

Q: What communication interfaces are available on the SR750?

A: The unit provides an RS232 front communication port, dual RS485 rear communication ports supporting Modbus RTU, and optional Ethernet communication supporting Modbus TCP.

Q: What current transformer inputs are supported by the relay?

A: The SR750 accepts 1 A or 5 A secondary current transformer inputs for phase and ground protection measurement circuits.

Field Installation Guidelines

Install the relay in a compatible protection panel using the specified drawout mounting arrangement. Maintain separation between power wiring, CT/VT signal wiring, communication cables, and high-noise switching conductors.

Terminate cable shields according to the site grounding design to reduce electromagnetic interference on measurement and communication circuits. Verify CT polarity, secondary wiring continuity, VT connection configuration, and control power polarity before energizing the unit.

Confirm communication parameters including Modbus addressing, baud rate, and network settings before connection to supervisory or control systems. Record installed firmware revision and configuration data during commissioning.

Specifications

• Brand: General Electric

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems