I can answer this for ya.....I think Holmes is on vacation...
Handwound motors provide more power than a machine wound equal, but there is no definitive answer. It's never been really tested much in racing, as machine wound classes in general don't allow handwound. There was some carry over in oval with the 19t class though, as they allowed handwound 19t motors, as long as they were in the same can as the machine wound. Two popular motors were the Reedy Quad Mag 19t and the Trinity C2. When we would build those machine wound, they would be in the mid 160s for watts. If we would handwound them, we would see mid 190s, so yer talking 30 watts, which is a LOT More power. And this is just on a 19t....power increases on modifieds would be more substantial, but a a definitive answer is tough.....mainly cause I as a motor builder can't really machine wind a 55t mod to compare to. I can't get the integy teardowns they use really, and wouldn't cause my experiences with their motors is that are made of not the best materials with fairly cheesy designs.....I had a failure rates that are through the roof with their 19t and stocks.
So is it worth it, I would say yes in a heartbeat......is it noticeable, well, I have never had a crawler customer complain they couldn't notice it.
What makes a handwound better, that's a lot easier to answer. First and foremost, you can much better windings, even if its not pattern wound. A sloppy handwound is still better by far than a machine wound motor. Copper gets packed in MUCH MUCH better, so you can more copper fill (other wise known as circular mills). Now keep in mind, this is a weird term. You want more copper in the fact of BIGGER wire, which is more feasible because of the handwinding, as you can pack it in better, but you want the overall length to be as SHORT as possible. Short and fat =more power and more efficient. Think of it as a fire hose......you want as much water as fast as you can....how do you do this? A FAT and SHORT hose......that's how power gets through a motor.
Handwound motors are typical either silver solder or silver welded, which is a MUCH better bond to the comm. Machine wounds are almostly ALWAYS compression welded....which sucks. It's not strong, resistance is much higher, so in the end, you are losing power and more likely for failure. This is big time important when you are stalling out a motor and it's drawing 100 amps.....weak links make things go BOOM.
Next up is epoxy, which is a bigger deal than most people realize. Epoxy holds the windings in place, keeping the motor in balance. It also increases heat disipation. Strong windings are extremely important to the motor lasting. Machine wounds do have epoxy, but its done the worst way possible. One of two ways is usually used, they either spray the windings (most common) or brushed (fairly uncommon). Handwounds done by quality motor companies, are DIPPED. Dipping is the only way to get make penetration into the windings. You want that epoxy to flow all through the windings, which doesn't happen with the spray or brush methods. An easy test for this, take some maple syrup.....spray it on a sponge, brush it on a sponge, and then dip a sponge in it......what gets the most syrup? I think the answer is obivious. You can test this by unwinding a machine wound motor and then get any quality handwound motor, the machine wound will unwind pretty easy, like just a flimsy glue holding it together......you will be lucky to even get a few strands of the handwound arm undone.
Epoxy then needs to be cured. Machine wounds are usually flash baked, which usually exposes them to a high heat for a minimal amount of time, or they use an epoxy does not need to be baked, it basically air cures. The best epoxys to use all require heat curing. You are getting a weaker epoxy on the machine wounds, but the best stuff is used on handwounds. Quality handwound arms are typically baked for 90-240 minutes, depending on the epoxy.
Comm cuts are done with diamond bits and measured by hand. You are getting a comm thats as perfect to round as we can get it. Machine wound motors, are simply cut to a preset on the lathe.....regardless if it makes the comm round or not. Out of round comms cause a loss of power, increased amp draw (aka heat), premature brush and spring wear, and it effects balance.
Balancing is very very different on machine wound vs a handwound. Handwound arms use precision balancers, made to balance ONE arm when done with the winding, soldering, epoxy, etc processes are done. Machine wound arms use a very very weird process. The winding machine often attempts to correct balance as it winds the motor. Remember how I said SHORT wire? Well, the machine usually adds wire to attempt to correct balance....BAD BAD BAD. They are then touched up on a machine thats much different than the ones we use. The machines I use (I have three) cost 9k, 10k, and 4k(this is an older portable model, not as good as the other two). Our machines allow us to balance much more efficiently, hence why you often see less and smaller holes on our arms.
A last thing to note on is the ability to modify whatever you want in the process with hand winding. You can change wire sizes, patterns, you can double dip the epoxy, and more. Machine wounds are all set to the pre determined settings and left to run.....there is very little human interaction inthe process. Think Homer Simpson pushing his button at the power plant.
Also beware, not all handwounds are created equal. Integy handwounds are done very very shody. If they were a 7 turn, they would explode within the first minute of a touring car race. They use very cheap epoxy, and sometimes its just sprayed on. They are not very good at the welding they do, and it spreads the comm plates far past whats acceptable and soldered versions use a a poor solder with the wrong type of flux, which is why the joint always looks nasty. Typically they are using a much smaller wire than they should, which is not always a bad thing, but it does produce less power, but it makes them much easier and cheaper to wind.
If yer looking for a good handwound motor, stick to the companies that actually do it (or a quality reseller like Holmes or JP) right from start to bottom. I know my company does it right (team brood racing), as does Fantom, Banzai, and Trinity.......really the only companies doing quality handwound motors for crawling applications. We do a ton of other things to these motors to justify the extra expense for them.
So simply said, the extra $20-$40 you would spend on a quality handwound motor is easily worth it. Look how much you spend on all the other stuff in your crawler. $100+ each for berg axles, $140 servos, $160 ESC, etc, etc......with a $20 motor? Look at any real crawler or race car, the motor will always be among the most expensive, if not the most expensive item on the vehicle.
Sorry for the long winded post, if you have any other questions, lmk.
Later EddieO
