Auxiliary generator drive assembly Manufacturer & Supplier – EMD 645 & 710 Parts

Overview

Separate from traction power, an EMD locomotive's auxiliary alternator handles everything the crew and the train itself need to run — cab lighting, HVAC, control-system power, and, on passenger units, head-end power sent down the train for lighting, climate control, and dining facilities.

How It Works in the Engine

This drive assembly is what transfers rotation from the main diesel engine to the auxiliary alternator. The alternator then splits its output across several voltage levels — low voltage to the exciter panels, medium voltage to battery charging, and higher voltage to blower motors, compressor drives, and radiator fan motors. A drive that's slipping or worn doesn't just make noise; it shows up as inconsistent output across all of those downstream systems at once.

Signs You Need a Replacement

• Coupling wear or backlash between the drive and the alternator shaft
• Bearing noise or roughness felt through the drive housing
• Auxiliary output voltage that fluctuates or sags under load
• Multiple aux-powered systems (lighting, blowers, battery charging) acting up together, pointing back to the drive rather than each system individually

Why Source This From Apex International

Drive shaft and coupling dimensions are checked against EMD/DLW references before dispatch, so alternator speed — and the voltage it produces — stays where the electrical system expects it, not drifting under sustained running.