Yep, that site does the same thing to me. There are actually two "Mean Green" arms. An 'original' Aurora has green wire, green tips. An American Line version has green tips, gold wire. It's sometimes easy to mix up a new AW arm with an American Line version if you only go by the colors. One 'giveaway' is the color of the comm (the bottom side that touches the brushes), the other is the resistance rating (ohms). Mean Greens read 5 to 6 ohms I believe. A Tuff Ones arm is red tip, green wire., usually read 6 to 7 ohms. And the red wire, red tip is called a "Red Devil". It's usually 14 to 16 ohms. Hope that didn't confuse ya. That website is a GREAT site to identify arms, but, like Joe stated, seems to wanna boot both me and him outta there. That's why I tried to help ya out here, just in case. If anyone else can help elaborate more on this, please jump in. ;D Ron (Bondo)
Drag Racing...Because if you can turn, you're not going fast enough!
The pictures didnt copy but here are the descriptions from SlotMonsters site.
AFX and magna-traction Armature Identification • Aurora Thunderjet 500 pancake motor armatures • Simco Guide to Rewinding Armatures • What is a pancake slot car chassis
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Edit Early AFX • OHM Range: 6.0 - 7.5 • Green Wire with Red Tips Originally available on the third generation "Tuff Ones" series of cars, these arms were also available on some of the earliest AFX cars as Aurora transitioned from 'screw-on' Thunderjet 500 bodies to 'snap-on' AFX bodies & chassis'.
The Tuff Ones also introduced the 14t Cluster Pinion which was carried over to AFX chassis's throughout their production run. These arms produce a fairly good mix of Top Speed and Low End Torque; and when run on 20V with the proper amperage these can really come alive... The early TO arms had Copper colored wire with later models having Green. To the best of our knowledge, only the green wire version made it into the AFX. Aurora decided to re-introduce the (Copper|Red) color combination on most of the AFX magna-traction (MT) cars throughout their production runs.
Use an ohm meter as your guide, as you don't want to confuse the earlier (Copper|Red) Tuff Ones armatures with the later, lower performing (Copper|Red) magna-traction arms. ________________________________________ back | top
Edit AFX magna-traction • OHM Range: 13.0 - 15.0 • Copper Wire with Red Tips Take into consideration that AFX magna-traction cars came with very strong, dual purpose magnets that not only powered the arm but also provided vehicle traction. The stronger magnets are probably why these arms ohm so high for Aurora's final Pancake offering. Not really a good performance choice in anything other than a MT car; although fair performance in a Thunder-jet 500 can be had with stronger AFX Super II™ or Johnny Lightning magnets.
As previously mentioned, don't confuse this arm with the similarly colored but lower better performing Tuff Ones arm.
An unusual version of this armature was available in European A|FX magna-tractions. This version had a Printed Circuit type commutator that sported a resistor or capacitor on each pole. It was suggested by Jim Sgrignioli of Yellow Jacket Performance that this was due to Europe's power not being as clean as U.S. & Canadian power. Cars equipped with this armature might also be found with a capacitor soldered between the pickup shoes, probably to even out A.C. voltage ripple and prevent surge damage.
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Edit Mean Green • OHM Range: 6.0 - 6.5 • Green or Copper Wire with Green Tips Designed for High RPM operation, this Arm (like the rest that follow) is of the typical Bi-Laminate design. The Green|Green version was available on some of the AFX cars, with some purists believing generally better results can be had with the Aurora version. It is meant to be used with the stronger AFX Super II™ Magnets but you'll find they also run well with Johnny Lightning Magnets in an Aurora Thunderjet 500 chassis.
Usually available as a separate item through American Line NOS (Copper|Green), this arm, when properly balanced, can attain very high speeds but is best suited for lighter weight cars & chassis's due to it's torque profile; cars that have been lightened or use lighter bodies (like Cheetahs, Falcons, Lola's, GT40's or some of the lighter aftermarket resin racing bodies) benefit most from this arm.
If using weighted rear wheels, avoid using ones too heavy if road racing on technical tracks requiring you to dramatically slow down and speed up repeatedly (like a track with many 6" curves). Complete NOS AFX Gearplates from American line containing the Green|Green version are still available and it is widely thought that they contain the genuine Aurora parts. ________________________________________ back | top
Edit AFX "Red Devil" • OHM Range: 14.5 - 15.4 • Red Wire with Red Tips Usually found on AFX and/or early AFX magna-traction cars. There is some speculation on which cars contained this fairly rare arm, with some suggesting Canadian origination after Aurora's U.S. facilities had closed.
Whether intentional or not, the 4 Green (I think you meant Red?) Devil arms we've inspected all have the commutator plate slightly rotated counter-clockwise by 2-4 degrees (if viewed from bottom) leading to a slightly retarded timing curve, suggesting higher top end. This better than average arm can perform well when matched with either AFX Super II™ or Johnny Lightning Magnets and a 14t cluster pinion. ________________________________________ back | top
Edit Specialty Cars (Drag Arm) • OHM Range: 7.0 - 7.5 • Copper or Green Wire with Blue Tips These are found in the AFX Specialty cars like Dragsters and Funny Cars. These cars had longer chassis's that had a total of 4 gears and were usually pretty heavy.
Heavier gauge wire was used, so this arm tends to run hot. Stronger magnets and chassis or body cooling considerations are a must if used for Enduro Road Racing. This arm can typically used in heavy customs or performance projects using weights or weight pans. A popular application is in HO Drag Racing, since the main characteristic is Low End Torque.
When Road Racing this arm will launch your car from a dead stop, but others will soon be passing you due to its lack of top speed. You might consider it for Road Racing when on a very technical (lots of turns) track since it can really barrel out of a turn. You should realize that the A|FX Specialty chassis this arm was found in came with large diameter wheels, with the Dragster tires having an O.D. of .500 (half an inch), so even though this arm typically isn't capable of high RPM, the taller tire provided a higher top end speed!. If you are going to Road Race this arm, check our gearing discussion and consider going to a taller gearing profile to compensate for its lack of all-out RPM. ________________________________________ back | top
Edit Super II Quadralam • OHM Range: 4.0 - 4.5 • Copper Wire with Black Tips This arm is probably the most sought after Aurora factory arm. It is VERY fast (68,000 RPM @ 15v) and is unique as compared to the other available armatures, netting excellent top speeds while still providing low-end torque. This arm gets its name due to the fact that it has 4 laminates (lams) while others from Aurora offered 2 or even 1 lam.
Initially available in the early 1970's on the ill-fated and under-rated AFX Super II™ car, which also came with a special-edition Aurora Black Chassis out-fitted with Brush Cups, Chassis Weights, a Unique Armature Gearplate, Braided Shoes and Special Guide Pin straight from the factory.
The Armature as Aurora produced it also sported a 'double-wire wind', special advance curve and had a special silver-plated commutator plate; and all for $12-$13 at the time! No longer in available as NOS, they still pop-up used on eBay every once in awhile with complete cars going for around $200-$400.
A variant of this Armature was used in the XLerator cars. Precision replicas of this Armature are available via AG&G Hobby.
The pictures didnt copy but here are the descriptions from SlotMonsters site.
Seems like a few people are interested in checking out the armature guide on the SlotMonsters' site. Here is an abbreviated guide with the specs, but minus the history. Includes the photos. For those who need a quick reference to determine what arm and magnets they are working with.
Post by Bananasmoothie1975 on May 10, 2011 12:09:11 GMT -7
Been thinking about capacitors and dc motors for a while now.
Rather than to even out voltage ripple (bigger electrolytic caps are used for this), I'd guess they are more for absorbing the huge voltage spikes generated in the armature coils to reduce electrical noise and arcing. Most dc motors use small ceramic type caps for these reasons, but we seem to neglect them on our overpowered little cars.
Mind you, the Australian release of Mega G cars have THREE caps soldered between the brush barrels!
Hey Banana Agree with the electrolytic caps for ripple. Never seen caps on arms, I would think depending on where they're wired in would tell you if they're for generated or supplied spikes. The brush barrel thing sounds like supply problems. Not sure how arm (electromagnet) would create spikes. Wow! Smoke coming out my ears. Phew - please, educate me on this generated thing. ........................PC
Not sure how arm (electromagnet) would create spikes.
Voltage spikes occur when any current carrying coil of wire is switched off, and there's 3 of them on your armature.
For a test, put a volt meter across your rails near a running motor on the same rails, and watch how the voltage reading fluctuates wildly.
For another test, hold one end of a spark plug lead while the engine is turned over, you should feel the interaction of 2 wire coils and a collapsing magnetic field as a big SHOCK through your body... (please please don't really do this!!)
Think I got it - Spikes occur during discharge of individule coil. These discharges would occur twice in every rotation of arm(I think). Voltage reading from rails through running motor shows constant charging and discharging. I'm not sure if I understand the brushes tied with caps. Seems they would control incoming and outgoing current. Do they have a backup type effect through arm coils? Oh been zapped through plug wires with cracks in them. Hurts like a ....... well lets just say hurts. Never thought of them having a magnetic effect. ............thanks, PC