The commutator is what the brushes contact, from the commutator the power goes to the motor windings. The way these motors are designed the right and left sides of the motor windings are bridged across by the clips (I don't think there is a common name for the clips). Essentially a lot of current passes across the clips. FYI: The PMG is designed with brush side holes in the housing and fairly free large vent openings in the opposite side of the housing. What I have found is putting a fan (leaf blower - sans leaves) on one of the openings on the brush side moves a lot of air and thus heat out of the motor - of course we're talking when the bike is stationary ;-)
The fan shroud I have built mounts 8 of those small fans, and based on my extensive testing (;) with the weed whacker, er - leaf blower I think I will be able to move a large % of heat BEFORE it saturates the motor. I am NOT putting in a thermostat to turn on the fan but may use one to continue to run the fans until motor temps drop to some set level. As a further FYI: I ran 13 miles each way to Boulder, and back to Broomfield at a speed of 55MPH without overheating the motor, ie. the motor frame was not too hot to hold. My analog ammeter showed a max of 200, but amps mostly showed between 20 and 100. I gradually increased current and watched the ammeter to prevent wasted energy in heat. My temps reading the motor clips through the brush side opening have never registered much more than 240F degrees (and that was only once). I have read all the posts here, and am very skeptical of the NEED for the kevlar band, particularly the effect it may have on heat dissipation. So my money (literally) is riding on cooling air from turn on until the thermostat opens the fan circuit. I know a box fan would be more effective per a previous post but I will try the radial fans first, if I have to go with the box fan that means one side of the motor may get more attention than the other (just based on the physical mounting of my motor and the frame of the bike. One might ask how do I make the fan run after the on/off switch is flipped. Well the first thing comes to mind is a relay, energized when the main switch is on that directs power from the 72VDC to 12VDC converter to the fan assembly. When the main switch is off the relay goes into it's rest position and directs power from one of my 6 batteries to the fan assembly through the thermostat switch of course. So yes that means one of my batteries will be unduly taxed but most times the bike will be immediately on charge and the miniscule current the little fans consume will be covered by charge current. Hope this helps. Jeff 84 Franken'ceptor (700 miles) -----Original Message----- >From: Andrew in Ann Arbor <[EMAIL PROTECTED]> >Sent: Jul 30, 2007 10:13 AM >To: [email protected] >Subject: Re: [ElectricMotorcycles] motor terminology, commutator > >On Jul 30, 2007, at 12:00, [EMAIL PROTECTED] >wrote: >> "i'm not sure on the technical >> terms but i think they are called the communicator the little metal >> blades spinning on the edges near the housing. > >Would that be the commutator? > ><http://en.wikipedia.org/wiki/Commutator_%28electric%29> > >Andrew in Ann Arbor >technology is the answer, what was the question? > >
