Orion chrome

Stock RS Rebuildable

ot too long ago, I tested Team Orion's* new TOP Chrome Modified motor. The company recently joined Peak Motors to develop another motor that incorporates totally new features. The result of their combined design efforts converts these two motor builders into manufacturers of the Orion Chrome Stock RS. Among the TOP Chrome Modified's innovations were built-in capacitors; they allow enthusiasts to avoid having to solder capacitors to the motor's endbell task many find annoying.

The Chrome Modifieds were the first to use the new TOP design. Stock-class motors are far more popular in the U.S., and Team Orion's release of a stock mill has been highly anticipated. Let's check out the Chrome Stock RS.

* Can. The can's chrome-plated steel is 1.3mm thick at the top where the endbell is mounted. The round can features angled side vents-between the gaps in the magnetsand four large, triangular bottom vents, all of which allow airflow. Chrome plating has long been thought to trap more heat than other coatings do, but according to Team Orion, these larger vents compensate for any heat supposedly trapped by the plating.

The can's top edge features a 2.2mm-wide notch that is indexed with a tab molded into the endbell to prevent it from moving. The combination of the round can and the small notch in the endbell doesn't provide much security against tampering, but it does satisfy the requirements of the race-sanctioning organizations that allow rebuildable stock motors.

* Endbell. The Chrome Stock RSs endbell is very similar to the one on the Chrome Modified motor. It features a moldedcomposite base, aluminum brush-hood heat sinks and chrome-plated-brass brush hoods. The hoods are mounted on top of brass plates that are sandwiched between the heat sinks and the endbell. The brass plates serve two purposes: they improve current flow by pressing the brushes against the brush hoods with a tension spring, and they serve as "electrical traces" for the capacitors and allow the connection between them and the endbell's sides. The capacitors, much like those in the Chrome Modified motor, are built into the endbell and span the gap between the endbell's two sides and the motor can.

The Chrome Modified was the first motor to have built-in capacitors--an Orion/Peak innovation.

Another of the endbell's simple but practical features are its color-coded brush-shunt heat sinks. Located at the screw where a brush shunt with an eyelet would usually be attached, this motor's brush shunts are soldered into place.

The heat sinks are red and black-the universal colors for identifying positive and negative electric terminals. The color-coding provides a quick visible reference that's useful when you attach the motor leads.

* Armature. The armature is the Chrome RS Stock's most intriguing component. It features a conventional, dual-rotor design that's intended to increase rpm. Nothing unusual there; it's what Orion does to the armature that's unique. The outer surface of the armature's laminations has been machined, and so it has the step cut into it-instead of being formed as part of the original laminations.

The Chrome RS Stock's machined laminations have been the source of some controversial interpretations of the stock motor rules. The rules vaguely suggest that the armature can't be modified. Opponents say that machining the laminations is a modification, but supporters think that it's OK because the manufacturer supplies the motor already machined. This interpretation of the rules presumes that only modifications made by the end user are illegal. We're not here to make a ruling for the racing organizations, but this is an important issue (see the "Is it legal?" sidebar).

Why machine the armature? Reducing its diameter increases the gap between it and the magnets. This presumably increases rpm but also reduces torque. The step that is machined across the laminations modifies the armature's magnetic field and effectively increases the motor's timing without moving the endbell (a feature first seen on the original Trinity Paradox motor).

The armature also features a standard 0.300-inch-diameter commutator with a locking device and an identification tag for tech inspections at the racetrack.

CONCLUSION

The TOP-based Chrome RS Stock brings Orion into the realm of rebuildable stock-class racing motors. In the dyno test's power figures, the Chrome RS Stock falls a little short of the benchmark P2K motor. For average power output and torque, however, the Chrome RS closely matches the Reedy Rage Type-R and the GM Pinnacle Gold motors, but is roughly SOOrpm short of the Pinnacle Gold and more than 1,800rpm shy of the Rage at peak power output. As long as you change the gear ratio to compensate, rpm itself isn't overly important, and the Chrome has enough torque to pull a slightly taller gear ratio. The Chrome RS motor does show the highest efficiency in the current crop of rebuildable stock motors, and will help those who place a premium on run time.