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Originally posted by: Oogle
This "wear and tear" that everyone speaks about is very minimal, if not, non-existant. The spinning device doesn't run on gears like a car engine. It runs on an electric motor. That means there are no connecting parts between the spindle and the motor. There are probably just ball bearings or fluid to reduce viscosity. This also means that the GC has no brake pads either. The motor itself acts as the brake by stopping it's pole oscillation. That's why the disc keeps spinning when you turn off the power. When the motor is off, there's nothing to stop the spindle from spinning.
Ugh! Look at the diagram on the web page you linked. What connects the battery to the rotor? That's right, electrical contacts. Whenever an electrical contact that has current running through it is broken there is a spark (even if too small to see). These sparks tends to build up carbon on the contacts, increasing both mechanical and electrical resistance. Also, the more current you have to put through these contacts, the bigger the sparks formed, and the faster gunk builds up. Eventually, it kills the motor. Now, to spin up a disk you need to supply enough torque to accelerate it and enough torque to overcome drag/friction. Once you have the system spun up, you only need to match the torque from drag/friction. Thus it takes more current to spin the disk up (especially if you want to spin it up fast), and spinning up is harder on the motor than maintaining speed. There are more falure points to the system than this, though. Running currents through the wires generate heat. Rapid changes in current through a wire tend to lead to temperature differences in the wire, causing it to bend under what are called thermal stresses (e.g. what breaks the filament in an incandescent light bulb is the rapid heating and cooling that causes the filament to bend). These are the two immediate failure modes that come to my mind, and note that both are most likely during spin-up. I don't know if they use such motors, though. For instance, it is possible to rotate the magnet and surround it with coils. This is conventially avoided because it requires more wiring, but it is more reasonable to control such a motor with a solid state circuit. Though that would require some sensor so that the circuit knows how fast the motor is running, and that sensor becomes another failure point (though it seems like it would be less susceptible to damage from spin up and spin down). You'd have to ask an enginner to find out about other possible ways for a motor to fail. The ball bearings come to mind as one, though I don't see a reason they would care about the amount of torque on the spindle (except, of course, in the situation where the force on the spindle is not a perfect torque, and the ball bearings need to provide extra force to keep lined up).
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So, actually the opposite is true. It's more likely a good thing to see that the disc keeps spinning when the GC is turned off. It shows that there is very little friction between the spindle and the ball bearings/fluid. If it were to stop immediately after powering off, I'd be worried that the ball bearings are broken or somehow fused to the spindle.
You missed the point: the poster wanted to know why the disc never spun down during play, even if the system was just sitting there for a 1/2 hour.
BlackGriffen
Topic: Mini-games in Modern Games are Boring (Read 6359 times)
