This type of capacitor uses a metallized paper or plastic film as an element. This capacitor is also known as a "self-healing SH capacitor". Although most of the previous capacitors used paper elements, the plastic film capacitor has become mainstream in recent years due to its compact design. The rated conduction time is the minimum design life of the capacitor when operated at the rated load, rated voltage, rated temperature and rated frequency.
The standard life expectancy is 40, hours. A capacitor that breaks at the end of life may smoke or ignite. We recommend that the capacitor be replaced after the rated conduction time to avoid potential issues.
Oriental Motor products use capacitors with UL recognized safety features that have passed the UL requirement of a 10, A fault current test. Capacitors are rated in capacitance, working voltage, tolerance, leakage current, working temperature, equivalent series resistance For the purpose of motor matching, the 2 most important specifications are capacitance and working voltage. The voltage rating is typically about double the value of the motor's rated input voltage in volts there's actually a formula to determine the capacitance for a motor, but we'll save that for later.
These specifications are listed on both the motor label and the capacitor label. The use of a capacitor with a different capacitance can increase motor vibration, heat generation, power consumption, torque variation, and unstable operation. If the capacitance is too high, motor torque will increase, but overheating and excessive vibration may occur. If capacitance is too low, torque will drop.
Using a capacitor exceeding the rated voltage may cause damage and the capacitor may smoke or ignite. Every single-phase AC motor from Oriental Motor includes a dedicated capacitor that is sized for the motor to operate at its highest efficiency and performance. No capacitor sizing is necessary. To ensure that the motor is operating at its highest efficiency, always use the dedicated capacitor that is included with the motor. The dedicated capacitor creates a 90 electrical phase shift from the auxiliary capacitor phase to the main phase.
Using the wrong capacitor can shift this away from the 90 degrees, and the resulting inefficiency can cause the motor to overheat with inconsistent torque or speed performance. Notice "Rated Speed" and "Rated Torque". This operating point where these two intersect on the curve is where the highest efficiency occurs.
Every motor is designed for a rated load. This is why oversizing isn't the best way to size AC motors. A difference in the capacitance in the capacitor will affect both rated speed and rated torque as the operating point shifts away from its maximum efficiency. If you use 2 of the same exact motors with vastly different capacitors, you will produce vastly different results.
Once maximum efficiency is lost, heat generation increases for the motor. You can find capacitors as big as soda cans that hold enough charge to light a flashlight for a minute or more.
Even nature shows the capacitor at work in the form of lightning. One plate is the cloud , the other plate is the ground and the lightning is the charge releasing between these two "plates. Here you have a battery, a light bulb and a capacitor. If the capacitor is pretty big, what you will notice is that, when you connect the battery, the light bulb will light up as current flows from the battery to the capacitor to charge it up.
The bulb will get progressively dimmer and finally go out once the capacitor reaches its capacity. If you then remove the battery and replace it with a wire, current will flow from one plate of the capacitor to the other.
The bulb will light initially and then dim as the capacitor discharges, until it is completely out. In the next section, we'll learn more about capacitance and take a detailed look at the different ways that capacitors are used. One way to visualize the action of a capacitor is to imagine it as a water tower hooked to a pipe.
A water tower "stores" water pressure — when the water system pumps produce more water than a town needs, the excess is stored in the water tower. Then, at times of high demand, the excess water flows out of the tower to keep the pressure up. A capacitor stores electrons in the same way and can then release them later.
A capacitor's storage potential, or capacitance , is measured in units called farads. A 1-farad capacitor can store one coulomb coo-lomb of charge at 1 volt. A coulomb is 6. One amp represents a rate of electron flow of 1 coulomb of electrons per second, so a 1-farad capacitor can hold 1 amp-second of electrons at 1 volt. A 1-farad capacitor would typically be pretty big. It might be as big as a can of tuna or a 1-liter soda bottle, depending on the voltage it can handle.
For this reason, capacitors are typically measured in microfarads millionths of a farad. If it takes something the size of a can of tuna to hold a farad, then 10, farads is going to take up a LOT more space than a single AA battery! It's impractical to use capacitors to store any significant amount of power unless you do it at a high voltage. The difference between a capacitor and a battery is that a capacitor can dump its entire charge in a tiny fraction of a second, where a battery would take minutes to completely discharge.
That's why the electronic flash on a camera uses a capacitor — the battery charges up the flash's capacitor over several seconds, and then the capacitor dumps the full charge into the flash tube almost instantly.
This can make a large, charged capacitor extremely dangerous — flash units and TVs have warnings about opening them up for this reason. They contain big capacitors that can potentially kill you with the charge they contain. In the next section, we'll look at the history of the capacitor and how some of the most brilliant minds contributed to its progress. The invention of the capacitor varies somewhat depending on who you ask.
There are records that indicate a German scientist named Ewald Georg von Kleist invented the capacitor in November Several months later Pieter van Musschenbroek, a Dutch professor at the University of Leyden, came up with a very similar device in the form of the Leyden jar , which is typically credited as the first capacitor. Since Kleist didn't have detailed records and notes, nor the notoriety of his Dutch counterpart, he's often overlooked as a contributor to the capacitor's evolution.
However, over the years, both have been given equal credit as it was established that their research was independent of each other and merely a scientific coincidence. The Leyden jar was a very simple device. It consisted of a glass jar half-filled with water and lined inside and out with metal foil.
The glass acted as the dielectric, although it was thought for a time that water was the key ingredient. There was usually a metal wire or chain driven through a cork in the top of the jar.
The chain was then hooked to something that would deliver a charge, most likely a hand-cranked static generator. Capacitor is basically formed from an insulator and two metal plates that are attached on the both sides of the insulator. Insulators do not carry current. The insulator used for capacitors is specifically called as dielectrics.
While the electricity is flowing, the positive and negative charges are transferred within the conductor. Charged with the electricity, the flow of the charge is started, but it is blocked since there is an insulator between metal plates.
Then, the charges are built up on only one of the two metal plates. Meanwhile, another metal plate attached to the insulator has opposing charge. Thus, capacitors have a structure to store the electricity between the two metal plates.
For materials of insulator, gases, oils, ceramics, and resin are used. As for shapes of the metal plates, there are a wide variety of types with parallel plates, foil wrapping, multi-layers, and so on. The amounts of stored charges as well as the supported frequencies are different depending on the types of insulators or the structure of capacitors.
So, it is necessary to select a suitable capacitor to meet your requirements. For details regarding storing electricity, please refer to the above-mentioned Basic structure of a capacitor. As the electric charge is stored between the metal plates, the electric charge transfer is stopped, making DC stop flowing. However, in other words, until capacitors are fully charged, even DC can flow for a short period of time. In the case of AC, the current direction is switched with a certain interval, and then, a capacitor is charged and discharged.
Therefore, the electricity looks like passing through the capacitor. Accordingly, the higher the AC frequency is, the easier the passing is through capacitors.
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