AMR Ground Check System GM-300 Installation and Maintenance Manual

About this manual

This manual provides step-by-step instructions for installing, operating, testing, and troubleshooting the AMR GM-300 Ground Check System. It covers component assembly, wiring, sensitivity adjustment, and fault diagnosis. The system monitors pilot and ground wire loop resistance and includes optional trip indicators and batteries for enhanced functionality. All field repairs are possible down to the board level, with replacement parts listed in Appendix B.

What's inside

• Introduction
• Operation
• Test Switch
• Sensitivity
• General Information
• Optional Trip Indicator
• Optional Battery
• Troubleshooting
• Test Reading
• Output Contacts

Specifications

Frequently asked questions

How do I test the GM-300?

Press the test push-button. As the normally closed contact breaks, the GM-300 will detect an open circuit, one PLUS LIGHT goes out, and the “HIGH” ohms light will blink; then the normally open contact will make and a 9 ohms test resistor will be connected in the circuit.

What does the GM-300 monitor?

The GM-300 senses the external resistance between its ground and pilot terminals, including the resistance of the pilot wire, ground wire, and any other resistance in the electrical path.