3573 replies to this topic

[Slotgeezer]

I agree... Love the color ( now, THAT's a surprise, eh? ) ...

That version of the Mura C-can set-up was my favorite version... The "trapazoid cut-out" set-up... We refered to them as "trap-cans"... 12's, 15's, 20's, & opens would spin like crazy, & the added ventilation worked VERY well...

& notice the resemblance to their current set-up... The same bar across the vent, to allow return-path for the magnetic field...

Great job, John... But, then again ... Would I expect anything less ????


Jeff Easterly

[Alchemist]

The motor color reminds me of the Gulf Ford GT40 - awesome car! Awesome motor John!

[havlicek]

Hi Ernie. I was waiting for someone to mention the GT40 (even more so with the orange leads). It would be pretty neat to build one for this motor. Talk about "color-coordinated"

-john

[Prof. Fate]

Hi

But if it doesn't blister the paint, it isn't "Hot" is it?

Grin.

Fate

[havlicek]

...nah, this one is a (sort of) "mild" factory Mura wind (X-12). I don't think it will blister any paint, but it should be a real strong runner.

-john

[Slotgeezer]

...nah, this one is a (sort of) "mild" factory Mura wind (X-12). I don't think it will blister any paint, but it should be a real strong runner.

-john

Them Mura X-12's were good, all around performers.... We raced them in a GTP / GT class, that allowed "any C-can set-up, single-piece ceramic magnets, & a .510" minimum dia. armature.... Shunt-wires & ball bearings are okay"...

A few guys were racing the .510" Camen arms, but most of us ran the Mura .513 arms... Great stuff


Jeff Easterly

[havlicek]

Repairing an earlier G20 car for a blogger (Champion chassis/Mura motor), I wound this arm:


It's a #27 that I think is close to what's supposed to be in the Mura setup that's in this car, done on a salvaged Mura .007" arm. The arm that was in there was toast, two poles dead. It was a nice looking French silver wind...at least it says "French" on one pole, "30 degrees" on the next pole and "16D" on the third pole.

-john

[Slotgeezer]

AWESOME!!!!!


Jeff Easterly

[havlicek]

Hi Jeff and thanks It's a shame really that the original arm was toast since it looked so cool. Looking at the original under a good light and with a magnifier, I couldn't see anything wrong with it at all...but I got nothing on the meter for two out of three poles. It also didn't show any shorts between the poles and the stack or shaft so the only thing I can think is that there are breaks in the coils internally???

-john

[Slotgeezer]

Well, if it shows no continuity, then it's a "dead player", all right!

I just love the way that the 38T you put on that salvaged blank fills the pole almost to the max... There's something about moderately-sized wire wound on a blank that seems to get the effect of good RPM & good torque... The "balance" that every winder is searching for... That way, you can adjust gearing to suit track design, & still get great life out of the armature... Runs warm, but not hot... Great "punch" & brakes, without "lugging" the motor... Good RPM, but not rubber-melting speed...

All things in moderation & balance...

Thanks, John...


Jeff Easterly

[havlicek]

Hi Jeff,

I just love the way that the 38T you put on that salvaged blank fills the pole almost to the max...

yeah, this was the old Mura blank with the thick poles and if I used a popsicle stick to jam it on there, I might have been able to get maybe another 5 turns on there max. The exact same wind (even with a couple more turns) on a modern blank looks scarey light (although they will be close to the same on the meter...around .3 ohm). The 38/27 wind is a really nice balance and I think I've done about a half dozen of them in the last 6 months or so. Interesting here because I was sent the whole car and with so-so magnets (they measure around 875 on my meter when the real bad boys go to something like 1100) and loading the motor to spin the drivetrain, the current draw goes from something like 1.4 amps (no load) to 2.5 amps. I have to believe that on the track when you punch the thing, it probably shoots to 5 amps for a split second??? Amazing that such a wind is considered sorta tame compared to flat out open motors

-john

[Slotgeezer]

That kinda amp draw, w/ those numbers on the magnets...

Amazing .....

I've had shop owners tell me that even racing a field of 8 - Boxstock wing cars, the initial amp-draw when "power is coming on NOW!" approaches 20 amps per-car, for a few nano-seconds, due to each motor grabbing current to begin the spinning process... Just think of the current draw for 8 - 16T24 open cobalt motors!



Jeff Easterly

[Prof. Fate]

Hi

As the magnets get better, as with cobalts, if you got the field right, the draw goes DOWN as the motor is more efficient.

In '68 when we agreed and voted on the NCC for 69 rules, the 27 was the standard G.20 wind (45 turns). 26s were common on short tracks and 24s on long tracks. But with ceramic magnets of the time, THAT is when you get a 15/20 amp surge. In this era, a lot of powerpack driven tracks were still around and that was the problem.

Anyway, the spec G20 arm was a mura only item for the first couple years. When that was opened up later, I don't remember that French was still making arms. In any case, this is the beginning of tags and a 27s wouldn't have been engraved that I remember.

Fate

[havlicek]

Now that I look at it, the engraving seems newer than the arm itself and in any case, it was done after the arm was dyed. I'm guessing that the information (whether accurate or not) was added by someone later on. In any case, the arm is as dead as a door nail.



-john

[BoomerDog]

Hi, John,

Is this arm going to be a new project? What do you have in mind for winds?

[havlicek]

Hi Steve,

No, the arm pictured above is out of a Champion steel chassis with a 2-hole Mura motor and is dead. I wound one to replace it:


I had just thought that it was a shame it died, as it was a nice looking arm with that silver wire and all.

-john

[tonyp]

I am no expert but I honestly don't remember any production engraved arms until way past the French era.... It was engraved after dykum was added and that also came after French era.

[havlicek]

Thanks for that Tony, that's what I figured as well. Maybe it's a counterfeit

-john

[don.siegel]

or a real French guy....

You know John, you're going to have to do an index of this thread pretty soon, to help us find the right page!

Don

[tonyp]

John, the arm is probably real but dyked (is that a word?) and engraved much later. The silver wire looked great. I remember using the simco stuff. It was the best motor and last I ever wound. 50 turns of 28 I think.....

[BoomerDog]

The replacement is beautiful, John. Have you set aside a burial place for the dead arm?

As you know, I've been following this thread for quite a while, John, and your work just keeps getting more astounding. You should start your own line of arms...

[Bill from NH]

It was engraved after dykum was added and that also came after French era.

The first dykum I remember being sold for dyeing arms was dark blue rather than the green/gold shown in the photos.

[BoomerDog]

Tony P.,

Seems like 50 of #28 is a pretty popular wind according to all the posts through this thread. In your experience, does that seem to give you improved motor performance and durability or as John likes to call them "a mild wind"?

I remember rewinding an old Russkit 22 back in the day with 65 of #30 and not knowing much at the time (I'm sure I don't know much more now ) probably spun the timing up pretty good, too. It was a runner and lasted quite a long time.

[tonyp]

The standard where we raced on powerpacks was 60 of 30, 55 of 29 or 50 of 28 if you cound get it on the armature. Back then the 28 wire was a hot wind.

[idare2bdul]

The standard where we raced on powerpacks was 60 of 30, 55 of 29 or 50 of 28 if you cound get it on the armature. Back then the 28 wire was a hot wind.

I didn't really start racing till 1975 so most tracks had replaced their original power supplys or augmented them with batteries. A coupe tracks like Circle T, in North Hollywood were pretty touchy about popping a circut breaker if you put anything serious on the track.

There was a tagged 26 arm for a format that didn't catch on. I believe it was 26 turns of 26 wire. While I have heard of them I've never actually seen one. I would think that this wind would have been a better idea than group 27 as it was a lot less trouble to wind and had slightly more power and seemed to handle heat well.
A side benefit was the 26's seemed to run well in the Mura cans where the holes had been opened up for group 27 or in the smaller 2 hole set ups that were used for opens.