What type of capacitor is used to start a motor?
Start capacitors usually have ratings above 70 µF, with four major voltage classifications: 125 V, 165 V, 250 V, and 330 V. Start capacitors above 20 µF are always non-polarized aluminium electrolytic capacitors with non solid electrolyte and therefore they are only applicable for the short motor starting time.
Are all start capacitors the same?
Start Capacitors It varies, but a start capacitor will measure between 70 and 120 micro Farads.
Can I use a run capacitor in place of a start capacitor?
In unusual circumstances, a run capacitor could be used as a start capacitor, but the values available are much lower than the values usually available for dedicated start capacitors. The capacitance and voltage ratings would have to match the original start capacitor specification.
How do you size a motor start capacitor?
Multiply 0.5 times the square of the voltage. Call this result “x.”. Continuing the example, you have 0.5 times 11.5 volts times 11.5 volts, or 66.1 square volts for “x”. Divide the start-up energy requirement, in joules, of the motor by “x” to arrive at the capacitor size needed in farads.
Can I replace a start capacitor with a higher UF?
An electric motor start capacitors can be replaced with a micro-farad or UF equal to or up to 20% higher UF than the original capacitor serving the motor.
What happens if starting capacitor is too big?
This is not to imply bigger is better, because a capacitor that is too large can cause energy consumption to rise. In both instances, be it too large or too small, the life of the motor will be shortened due to overheated motor windings.
Can you use a different capacitor?
Replacing a capacitor with something that has a higher voltage rating is always safe. The only problem there is that a capacitor rated for a higher voltage is often physically larger, everything else being equal. Make sure they actually fit in the same space.