Mell Can I replace a 370v capacitor with an 440v?
Many techs think they must replace a 370v capacitor with a 370v capacitor. The voltage rating displays the “not to exceed” rating, which means you can replace a 370v with a 440v but you cannot replace a 440v with a 370v.
Can I use a higher rated run capacitor?
As a general rule of thumb, electric motor start capacitors can be replaced with a micro-farad or mfd rating equal to or up to 20% higher F than the original capacitors serving the motor.
What should the voltage be on a microfarad capacitor?
Typically you’ll see a rating in microfarads like the 25uF in our capacitor photo above, and you’ll also see a voltage range rating such as the 370VAC (maximum voltage) rating also in the red circle of our photo above. If the capacitor markings are legible, they’ll be able to match it.
What is the MFD rating of a start capacitor?
2) Starting capacitorsare housed in a black plastic case and have a mfd range as opposed to a specific mfd rating on run capacitors. Start capacitors (ratings of 70 microfared or higher) have three voltage classifications: 125V, 250V, and 330V. Examples would be a 35 mfd at 370V run capacitor and an 88-108 mfd at 250V start capacitor.
What is the voltage rating of a capacitor?
The voltage rating is the working voltage for the capacitor to reach 60,000 applied hours. If the heating or air conditioning unit increases voltage to the capacitor (for example: the capacitor is rated for 370 Vac, and is seeing 440 Vac from the unit), then the life of the capacitor will be lowered significantly.
What kind of voltage does a start capacitor need?
The voltage classifications are 370V and 440V. Capacitors with ratings above 70 microfarad (mfd) are starting capacitors. Run capacitors are designed for continuous duty, and are energized the entire time the motor is running. Single phase electric motors need a capacitor to energize a second phase winding. This is why sizing is so critical.