You will notice that most capacitors have numbers printed on their bodies to indicate their electrical characteristics (for example 20 uF) Smaller capacitors use a shorthand of three numbers showing the capacitance in uF (calculated as XY x 10z for the numbers XYZ) and the letter indicates the tolerance (J, K or M for +/1 5%, +/-10% and +/-20% respectively)
Conventional capacitors provide less than 360 joules per kilogram of energy density where a conventional alkaline batter has a density of 590 kJ/kg.
Motor Starting capacitors are typically non-polarised electrolytic types, while running capacitors are conventional paper or plastic film dielectric types.
Motor Capacitor Information FAQ
Hazards & Safety
Please be aware that capacitors can retain a charge long after the power is removed from a circuit; this charge can cause dangerous or even potentially fatal shocks or damage connected equipment. Service procedures for electronic devices will include instructions to discharge and remaining charge.
Using a Digital Volt Meter to test capacitance level
Most DVM’s have a capacitance measuring function, these operate by charging or discharging the capacitor with a known current and then measuring the rate/rise of the voltage. Digital colt meters measure the capacitance from nanofarads to microfarads. Ducati are one of the best manufacturers of capacitors