Analogies for Magnetism and Electricity w/ Ty Branaman
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You create electricity when you send a magnet through a coil of wire. Alternatively, sending electricity through a coil of wire creates a magnet. Solenoids are prime examples of electromagnets and are quite simple to create and analyze.
Motors also use electromagnetic force to function. A motor may have several electromagnets, and the current flow changes direction. We call that reversal of current “alternating current” (AC). When you measure a condensing fan motor’s amperage with the clamp on your ammeter, you don’t measure anything on the wire itself. Instead, you measure the magnetic field from the electrical current.
Motors also have varying numbers of poles. In HVAC, we often see 6 and 8-pole motors. On a motor, each pole acts as a stator that turns the rotor in the center. In general, the fewer poles you have, the faster the rotor will turn.
A good experiment to demonstrate the effect that poles have on rotation speed, as Ty shows, is to have several people work together to spin an office chair. Start with 8 people (stators) around the chair (rotor). Then, subtract 2 people after a few spins. Repeat. You will notice that the chair spins faster when you remove people. However, the number of poles on a motor impacts the resistance of a motor.
Power (watts) is a different measurement entirely. To get the watts or power measurement of an electrical component, you multiply volts by amps (V x A). As such, you will have greater power (more watts) when you have lower resistance and higher amperage.
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