Magnetism
As you may remember from grade school a magnet can attract metals that are iron (ferrite) or have iron in them. Magnets also have "poles" or ends that are defined as North and South. As you also may remember like poles repel or push each other away, and dissimilar poles attract. So, for example, if you had two bar magnets and tried to push their north poles together they would push away from each other, but if you brought the south pole of one bar magnet near the north pole of another bar magnet they would attract and stick together. Magnets have field lines that are invisible (but can be seen with iron filings and paper over the magnet), but exert a force nevertheless. These lines of magnetic force can impart electricity into wire (or a coil of wire) when that wire is passed through it. Magnetism and Electricity You may also remember that an electromagnet can be created by wrapping wire around a nail and then running electricity through that wire. We all remember picking up thumbtacks, paperclips, or nails with an electromagnet gemsmotor.com/12v-24v-dc-gear-motor made with wire, nail, and battery. I'm sure you also remember that the nail stopped being a magnet as soon as the electricity was shut off. So there is definitely a connection between magnetism and electricity. How Electricity is Produced via Motion What isn't as widely known is that when a wire is passed into a magnetic field electricity is produced. How much electricity depends on the size of the magnets and the force causing the coils of wire to spin near those magnets. By the way, the number of cycles per second (Hertz) matches the number of rotations per second of the machine generating electricity. e.g. household current in the United States flows at 60Hz so the machine generating the power spins at 60 revolutions per second1. If the production of electricity is via mechanical2 means then magnetism plays a vital role. Any time a wire is passed through a magnetic field an electrical charge is produced in the wire. The orientation of the magnetic field and the direction the wire is passed through that field determines the direction of current flow. This is how generators, alternators, and dynamos work. By creating electricity from the rotation of coils of wire through a magnetic field. Of course this means the wire-coil is somehow mounted such that it can rotate 360°. Alternatively, the magnets or magnetic field, can be the rotating member with the wire coils arranged around those magnets. Either way, as long as the coils are passing through a magnetic field electricity is "imparted" to the wires or wire-coils. 1 This is no longer necessarily true, but at one time it was critical that a generator spin at exactly 60 RPM. These days electronics can set the Hertz. 2 Ignores the piezoelectric effect. http://hubpages.com/autos/Future-Car-Electric-Motors
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If your unit is equipped with a double shafted motor expect to pay up to $300.00 or more for a new motor. These double shafted motors are rare in residential units but they do exist. Out of about a hundred motors in 2001 I only had one that was double shafted. Variable Speed ECM Blower for Added Efficiency Another medium ticket item for replacing is the ECM blower motor. This is variable speed and can be found on most high SEER units. Variable speed motors are more expensive than standard blower fan motors or condenser fan motors. However, they are more efficient than conventional PSC motors and have better although more sophisticated control. If you have a variable speed motor that is bad it is important to replace the motor with an exact replacement. Depending on the OEM of the equipment will depend on the cost of the part that needs to be replaced. Sometimes an after-market variable speed motor can be used. However, most brands have proprietary connections for the electrical. This requires an exact replacement is needed for repair when a bad variable speed fan motor is found. “The ECM fans are liked by a lot of people because they are quieter and they do a better job circulating the air,” he said. “We used to use the Evergreen ECM blower motor as a replacement for PSC motors but have switched to the MARS Azure™ Digi-Motor®. I would say about 30 percent of customers who have a bad PSC blower motor are upgrading to the ECM fans.”
“We use the Legacy PSC motor and the Genteq Evergreen ECM motor,” Knight said. “Most PSC motors are very similar in design, performance, and warranty, so we use Legacy, as it is most available from our supplier. Our techs like the Evergreen because it offers easier installation, and its setup features and options allow us to adapt to the various applications we encounter.” Source: www.achrnews.com/articles/128247-retrofitting-psc-motors-with-ecms Resource for Motors: gemsmotor.com/ac-fan-blower-psc-motor |
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