Demon 4499 laydown brush pack.
Excellent brush for laydown hoods.
Fits most stock motors.
Ideal for 27 turn and 19 turn motors.
Serrated and high power.
As fitted to Demon motors.
Solder on version.
Pack of 7 pairs.
I only use the XXX brush myself, as it is very low maintenance, and lasts about 50 runs. I make sure I keep it serrated, perhaps after every 3 to 4 runs. The serrations increase surface area and current flow and stop glazing, so performance is maximised. You can run a lighter pressure with the XXX brush and it is also low friction any way, so top speed is very good. The lighter spring Red +ve and green -ve are effective if you maintain a fast speed, as they give less friction. The silver brush does not burn like a cheaper brush. Red is more pressure on the +ve as the electrons have a harder time penetrating the dirty copper conduction layer, but they leap off onto the brush with less effort. For max torque the heavier purple springs keep the brush pressed down to prevent the arcing lifting the brush. Also you may use a sacrificial brush such as the 4499 for more acceleration, but they do burn up, especially on hot days. The higher silver brush such as the 4503, should give more power, but in a lot of cases the extra interface trauma actually causes the motor to lose power since the interface is erratic. Heat kills the brush , as does uncontrolled and unsympathetic vibrations. The hoods are the place where a motor can reach a climatic performance or cause performance sucking jerking. The round brush design in close tolerance anodised metal guide is a very good solution, and we are still waiting for Epic to invest a few pennies to improve the very poorly designed existing endbell. Make sure the brush snaps into postion. Always remember to replace the brush the same way you take it out, since it will take the shape of the comm. When the comm is cut small a new brush will hardly have any contact area, and can cause burning of the brush and comm. A short run in time will help. When the comm is near its minimum , about 6.8mm the overlap is extreme giving excellent performance, but the efficiency is lower and the heat developed increased, probably burning the brush in one run. Years ago, we used to cut new comms down just to get the extra performance. Remember that these are very cheap mass produced motors and tolerances are huge, especially recently I have noticed that the tools are either wearing out, and or, the operators are setting them up wrong, causing many poor examples to be produced. For example, the winds are thrown on too fast and with insufficient spooling tension resulting in loose wires round the stacks. These vibrate and move about causing the balance to go out and actually absorbing power. Insufficient winding varnish also causes wires to move . Luckily a thick superglue will stick the wires, before I balance. The factory balancing appears to be done at random with holes drilled all the way down to the shaft, which can result in the laminations flying off at high revs, with catastrophic results. I use a wide drill to balance as there is no point at all in taking metal off near the centre of rotation. Another very poor manufacturing problem lately is the haphazard staking of the wires to the commutator. The tool should press and weld all 3 tags simultaneously. However if they have (and they do) one pressure tip set at less pressure or offset you get a distorted comm, with often one segment set lower than the other 2. That is why I always true them. Also , sometimes the welding tip even misses the tags causing a no contact with the winding, or a failure of that segment as soon as it is used in anger. After the first couple of runs alot of stress settling and winding movement can occur. Therefore it is essential to take a little skim to check if the comm has resettled and worth getting a rebalance check if you can. After this the windings should stay pretty well balanced. Always true the comm after a meeting as the depth of cut will be a lot less than if you leave it and burn a deep trough and severe burning on the comm slots which cannot be removed. The can and magnets, I find are fairly consistent, since the magnets are mass produced and are fitted without too much variation, also these last few years they hold their strength very well. If your magnet loses any flux, it can be magnetised back up, but will only lose it again, since the domain binding material is losing its adhesion. Unless you want to remagntise every meeting, either don't worry about the magnets, or buy a new can. Well finally, do not keep loads of old motors since a new one will always perform better. The endbells are the worst offenders so get a new one if it is all tarnished and bent about. Also check that the bushes are not worn too much, since a worn bush in the endbell will spell disaster. Put the armature shaft (long end) in the bush and make sure it will only move about 2 deg max each way. The can bush takes all the load so that will probably wear out first. If you oil the bearing, use the minimum possible, since the oil will creep and will get on the comm if you are not careful. I guess that's enough for now. Nick