Quote:
Originally posted by Jnadke
Now, to connect my example to how PWM is applied to a motor. Okay, lets say we need to power a waterwheel with buckets of water. However, it takes too long to get the buckets of water. So, put a funnel above the waterwheel. Then, pour the water in, the funnel will drain and the waterwheel will spin, until the funnel is empty. However, it will keep spinning because of momentum (and inertia - an object in motion will stay in motion), kinda like how a bicycle wheel keeps spinning when it's not on the ground. The water wheel will keep spinning until friction in it's bearings stop it, or until you add another bucket of water to the funnel to keep it spinning longer.
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You're getting closer. PWM is all around us. What is needed is an explanation that a layman can understand (yes, it can be done). Here's an example of PWM in the real world: Ever push a child on a swing? The longer you push through the cycle, the higher the swing goes (more energy). At some "push-duration" (duty cycle) you can maintain the same height by just putting in the same amount of energy as you loose to friction. In the above example, the "chopping" frequency is, say, one push/cycle. Now imagine what happens as you decrease the frequency to one push/three cycles, one push/ten cycles, etc...
-Kevin