Capacitor

Capacitor

0 comments

 

We use several different Capacitors in our Control Panels here is a little history on the Capacitor and two of the Capacitors found in our Control Panels. The Start Capacitor and the Run Capacitor art the two most common in our Control Panels.

Capacitor- is a device for temporarily storing electric charge. 

In 1745, the Leyden jar was competitively invented by Ewald Jurgen von Kleist - 4 Nov 1745. Pieter van Musschenbroek produced the first working example in Jan 1746, with the name coming from Leiden University. In 1747 William Watson discharges a Leyden jar through a circuit and comprehends electric current. Michael Faraday discovered the first practical applications for the capacitor in trying to store unused electrons from his experiments. As a result, this led to the first capacitor made from large oil barrels. This discovery enabled us to deliver electric power over great distances. The unit of measurement for capacitors or capacitance became known as Farad in his honor the symbol F.

Benjamin Franklin found during some of his experiments with electricity that a flat piece of glass worked as well as the jar model. this helped him to develop the flat capacitor.

Start Capacitor- briefly increase motor starting torque and allow a motor to be cycled on and off rapidly. A Start Capacitor stays in the circuit long enough to rapidly bring the motor up to a predetermined speed, which is usually about 75% full speed, and then is taken out of the circuit, often by a centrifugal switch that releases at that speed. Afterward the motor works more efficiently with a run capacitor.

Start Capacitors have 4 Major Voltage Classifications 125V, 165V, 250V and 330V. The motor will not work properly if the centrifugal switch is broken. If the switch is always open the Start Capacitor is not part of the circuit, so the motor does not start. If the switch is always closed the Start Capacitor is always in the circuit so the motor windings will burn out. If a motor does not start the capacitor is far more likely the problem than the switch.

Run Capacitor- Run Capacitors are designed for continuous duty while the motor is powered, which is why electrolytic capacitors are avoided, and low-loss polymer capacitors are used. Run Capacitors are mostly polypropylene film capacitors and are energized the entire time the motor is running. Run Capacitor voltage classification of 370V to 440V.

If a wrong capacitance value is installed it will cause an uneven magnetic field around the motor. This causes the motor to hesitate ant the uneven spots, resulting in irregular rotation, especially under load. This hesitation can cause the motor to become noisy, increase energy consumption cause performance to drop and the motor to overheat.


Post a Comment

Comments

    Post A Comment

    « Back to Blog