Chopper technology is revolutionizing DC locomotive performance, offering significant improvements in usable power and reliability. Choppers act as a bridge between the diesel generator (or other electrical supply) and the DC traction motors on each axle, enabling Independent Axle Control (IAC).
Unlike traditional systems where all wheels were grouped together and controlled together by the alternator, choppers allow for dynamic torque distribution per motor, maximizing traction.
A good analogy for this is to think of a pickup truck. Old DC locomotive design was similar to old 4WD systems. All wheels spin at the same speed, all the time. This equal distribution leads to the potential for slippage. When one wheel slips, the locomotive has to cut power to all the wheels until grip is regained. Adding choppers give you Independent Axle Control (IAC), which is similar to current electronic AWD systems that deliver maximum torque to the wheels with the most grip. For example, a typical 260,000 pound locomotive might see its tractive effort increase from 65,000lbs to as much as 91,000lbs by recognizing which wheels have the most grip and distributing the torque accordingly. This increased pulling power means you can pull more cars – potentially reducing the number of locomotives needed!
Reliability is also improved when integrating Choppers into your design. When you shift the control of the wheels from the engine/alternator to the Choppers, the alternator is no longer responsible for managing the full range of power needed from idle to top speed. This allows the engine to spend more time at its most efficient range, and much less stress on the alternator/rectifier (which is a common point of failure). Additionally, in the event of a Chopper or DC motor failing, it can be isolated independently allowing the train to continue with only a proportional loss of power – typically around 25%.
Chopper technology first appeared in North American freight operations in the mid-2000s, initially adapted from light rail applications in Europe. While early designs faced challenges and proved less durable under heavy freight conditions, the engineers at Integral Control Systems have been refining this technology for over 15 years. Choppers for DC traction are the absolute most you can do with a DC traction motor equipped locomotive, and allow you to keep using the same trucks, brake rigging, and DC traction motors. Our new ITC (Integral Traction Chopper) incorporates these learnings to deliver a robust and reliable system capable of handling even the most demanding applications. Discover how our ITC can optimize your locomotive fleet and reduce operating costs – Contact Us today for a consultation.