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R ig h t, w hich arm h a s been sim u lta n e o u sly w o u n d ! Y es, the one o n the right. N o te that o n the oth e r a rm , the tu rn s o n the last-w ound pole has flow ed out o n the o thers - not good f o r the balance and perform ance. Y o u ca n learn a lot b y analyzing your blow n arm s. T h is M u ra 007 (far left) w a s cut off right in the m iddle to check the w ire laying. Note that sp ace h a s not really been u se d - the w ire h a s not gone o n in neat layers. The a rm ? Shortcircuit d uring a 24-hour due to in su lation bre akdow n of the Poly-Therm alex. Centre, the difference betw een a h a n d w ou n d arm (on left) and a m achine-w ound arm. Note that the h and-w o u n d w ire h a s gone on in a not very neat fashion, resulting in three b ig h ole s n e ce ssa ry for b a la n c in g it. 15 winding Learning to wind competitively will take time and lots of practise. Therefore, I suggest that you get any old armature you can lay your hands on, buy a couple of miles of cheap winding wire and start practising until you feel that you have really mastered the art. Experiment with wires thick and thin, single, double and triple, put on old Mabuchi coms and try the results. If you blow the arms, so what, they were not made to be competitive armatures anyway. Just rip off the old wind and try something else. The practise you get is invaluable and will not cost you much more than time. Don't try your hand on a serious tuning job until you can really wind. The right equipment is important. For the serious tuner, a WINDING MACHINE is indispensable. Winding can be done easier, faster and with more precision, which will show up in performance. The wire can be 'packed' tighter, meaning more turns in less space, which in turn makes for more power and less unbalance. Many of the winds I have mentioned are impossible when winding by hand alone. Just try to cram on 60 of 28 that way! With a machine, however. 75 of 28 can be done on a 16D-armature. There are not many makes on the market. Teddington's Mini Winder is the one we use, with good results, as some of you readers may have noticed from last year's National Championships here in Sweden. Price is only 19/11, so buy one for your club today. Other good ones are LaGanke and Cobra, both American, but I'm not sure these are manufactured any longer. You might try sending to the U.S. for these. Price is six bucks. First a few mods on the Teddington machine: the inside of the adaptor should be ground out slightly and the adapter epoxied to one of the halves -see figure. Now, as for winding, I will reveal a special technique we invented a long time ago. A s of writing this, we have hitherto kept it silent and we believe we are the only team - at least hore in Sweden - to use this. 8
When first embarking on simul winds, our Teddington gadget was modified as shown here: tape was wrapped tightly around a tile . . . .. . and the file then inserted In the hole on the machine. A few pieces of thick copper wire helped keep the file in place. Next, transfer som e w ire to two em pty sp o o ls. M u ra 25 copper w ire w a s used here. The insulatio n m ust be stripped off. U se fine em ery paper for this If you take a look at a run-of-the-mill armature, you can easily tell in which order the poles have been wound, since the last one will have its turns flowing out on the two other poles. Those of you who read and memorised the chapter on winding theory will at once realise that this is not so good: the coils will generate unequal fields and unequal back emf's. meaning parasite currents. The obvious answer, therefore, is to make the coils equal by winding them at the same time. Out of this thought, the technique of simultaneous winding was born. Simultaneous winding will require a lot more work, but once you have made your first successful armature, admired the beautiful work and watched its performance, you will never want to go back to the old pole-at-a-time method again. Of course, the technique described here is not quite simultaneous winding, but the next best thing, with a noticeable difference in performance when you have mastered it. The first thing is to further modify your Teddington machine. I will here describe the mods we did for making our first simul-winds. but you should think out a more elegant solution with time. Get a long, round file, with a max. o.d. of about 1/4 in., and start wrapping tape tightly around the middle. See photos. Wrap tape until the file can barely be inserted in the big hole on the armature holder. Insert the blank armature and tighten the screw. (We have re-tapped the hole and changed to a more sturdy screw.) For the next step, you should have two small, empty spools, the kind that Mura- and Cobra wire come on. Now, get out your wire, and on each of these two spools wrap on wire enough for one pole. Figure 22: M o d ify in g the Teddington w in d in g m achine. Figure 23: T h is arm h a s been w o u n d w ith the pole-at-a-tim e method: yo u can easily see in w h ich order the p o les have been w ou n d . Figure 24: W h e n strip p in g insulation off the wire, rem em ber to keep the 3/32 in. distance . . . for safety reasons. 9
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