Split Phase Single Phase Induction Motor part 2
Split Phase Motor
Typical split phase motors utilized in consumer products aim power from 1/20th to 1/3 of a horsepower. That's 40 watts to 250 watts for people who prefer metric units. They're commonly found in fans, blowers, or electric lawn mowers. within the split phase motor dimensional differences between the starting and stator windings are quite visible. The split phase motor during this slide was pulled out of a really old weakened clothing dryer.
The first thing you must note is that the motor label identifies the most properties of the motor. This one is 1/4 horsepower, which is 190 watts and runs at 1725 rpm. The corresponding synchronous speed is 1800 rpm, as this motor operates at 115 volts, 60 hertz, one phase AC power, and has four pole pairs. The slip is calculated at 4.2%, typical of this sort of a split phase motor. The motor frame is square. See the bare copper wire of the most stator windings on either side of an oversized laminated iron core. This iron core concentrates the force field generated by the windings. Cooling fan blades are attached to the roter, circulating ambient air to stay the stator windings from overheating.
Rotating the motor 90 degrees on the table allows you to peek deep into the inside of the motor and see the starting windings deep inside. The starting windings appear to be about half the thickness of the stator windings. The length of the starting windings is additionally much less
than that of the stator windings. This motor transmitted power on both ends of the motor shaft.
The left end had a drive belt attached to that, and also the right end had a pulley attached. Looking axially into the motor, the cage rotor underneath the motor frame. This frame is riveted together, so It won't be able to take this motor apart much further. Flipping the motor around on its back reveals the most label mandated by Underwriters Lab. This label shows the motor designed data discussed before, the motor, serial number, safety warning, and therefore the serial number of the motor from the motor manufacturer. It also clearly specifies that it's a motor designed for a garments dryer.
The thick gray, red, and orange wires connect external AC power to the coil windings. This pack up of the motor reveals the centrifugal switch mechanism. At rest, the grey levers shown within the closed position press against the brown colored non-conductive plate. Keeping the plate within the closed position allows a group of internal contacts to transmit power to the starting winding. because the motor accelerates, the force on the levers acts to push the non-conductive plate to the correct, relieving pressure on the contacts. because the split phase motor approaches its operating speed of 1725 RPM, the force from the extension spring isn't enough to stay the plate within the closed position. The plate moves to the correct and therefore the contacts open. As long because the motor runs at operating speed, the contacts remain open and therefore the starting winding remains disengaged from the circuit. And now it is time for something completely different.
So rotating one end of the shaft, the one that was attached to the belt. you'll see the opposite end of the shaft rotating. you may see these fins here as they rotate. And you may see where I'm putting my screwdriver, right down in there. That's our whole centrifugal switch mechanism.
There's a spring and a white lever. Right here, we have got our stator windings, those are the large thick ones. and so right down in here, attached to those little small plastic insulators, right down in there, that is what was talking about the starting windings. you've starting windings here, a pair of starting windings on the opposite side, and really on all four sides of the motor, you are able to work out the starting windings.
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