Repair Help

What is the difference between MFD vs. MF vs. μF?

Short answer- none. Some manufacturers use MFD (micro farad) and some use μF symbol. The farad is unit of Capacitance. Usually the Air Conditioner capacitors range between 5 and 80 μF.

What is the difference between 370 VAC vs 440 VAC Capacitors?

When a capacitor is rated 440 volts it will work for both 370 and 440-volt application. The 440V cap is not more powerful. It is just build better. Therefore, it can withstand voltage up to 440 volts. It is as extension cord rated for 600V-it can be used for 240 or 125 volts. All of PowerWell capacitors are 370/440 VAC. The 440 volt capacitors are more expensive to manufacture, as they have a ticker walls and better insulation that is the reason some small A/C systems will come with 370 VAC one. The 440 capacitor will last longer too, as it is build better. Another example is a cooking pan that is rated for 440 Degrees, when is used to cook lasagna of 370 degrees.

40+5 vs 5+40 capacitor.

Some manufacturers (Lennox etc.) enter the dual run capacitor specs with the fan capacitor first and then the compressor value. Most of the manufacturers use the “XX+X” type where XX is the capacitance for the compressor and X is capacitance of the fan motor.

What is the difference between ±3% vs ±5% vs ±6% vs ±10% in capacitor?

 That value is the same if you buy a bag of one lb. rice. It can be ±6% of the weight. The standard in USA is ±6%.

50Hz vs 60Hz vs 50/60Hz

        The Hz (hertz) in the AC voltage is the number of cycles of current changes directions per second. Where 1 Hz is equal to 1 cycle per second. In most of the Europe, Asia, Africa the 50Hz (fifty cycles per second) is used. In USA, Canada and most of the South America 60Hz (sixty cycles per second) is used.  The 50/60Hz means the product can be used in both Europe and USA. All of PowerWell capacitors are 50/60 HZ

CBB65 capacitor vs CBB65B capacitor

The CBB65 stand for a single capacitor and CBB65B stands for a dual capacitor

Run vs Start Capacitor

       Start capacitors are usually used only for a moment when the unit starts. The run capacitor helps to start the motor/compressor and also help that motor to run more efficiently. The start capacitor usually have a plastic shell, as they are not intended to run for prolong time. They have a relative high microfarad rating. The run capacitors comes in a metal shell and are filled with oil, to help dissipate the heat. The start capacitors fail mostly because the compressor doesn’t start as it should or the starting relay gets stuck closed for longer than it should. Before replacing the start capacitor, you should check the motor and the starting relay or the new capacitor might also be damaged. Most of the start capacitors have a resistor soldered across the terminals. This is done to prevent the arcing of the start relay contacts.

Repair Help

How to test a capacitor?

It the capacitor is visible bulged or terminals are burned the capacitor have to be replaced.

The only way to test a capacitor is using a Capacitance meter. The capacitor have to be discharged and disconnected from any wires.

If you try to use Ohmmeter that capacitor can to be “off” by 90% and still show general “OK” signs.

If the capacitor is plus or minus 10% of the labeled value have to be replaced.

How to properly discharge a capacitor.

The only way to properly discharge a capacitor is to use a resistor. You can use different value resistor. For example a 20K Ohm/5 Watt resistor works good

Why wires connected to capacitor are burned?

There can be two reasons:

  • The wire terminal’s was not crimped to the correct specs and was not tight enough. The connections was only in limited spots and the current that was passing through that spots was too high, causing that connection to get too hot and burn.
  • The compressor have too high amperage draw.
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