If the wrong
Incorrect installation and/or improper circuit application that subjects the capacitors to reverse bias may lead to performance degradation or catastrophic failure (short circuit) of the capacitor.
Yes, but it should be replaced with the appropriate sized capacitor ASAP. There isn't really going to be an immediate issue that I've ever seen with upsizing a capacitor temporarily but sometimes temporary becomes permanent and say they next guy doesn't have a 45/5 and says oh well I can go one size up.
A wrong size capacitor could cause the compressor to overheat and shorten its life, or not run at its peak efficiency. The lower voltage rating is also a problem. The life of the capacitor will be shortened.
Using improperly sized capacitors can have a variety of detrimental effects on the motor. If the capacitor's µF rating is less than the motor was designed for, the motor winding current will be too high. If the capacitor's µF rating is higher than the motor was designed for, the motor winding current will be too low.
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.
Any issue if I replace a 1.2uf 550Vac capacitor to a 1.5uf 450Vac on my ceiling fan? yes, you will change the circuit characteristic.
If the capacitor fails open circuit you probably won't be able to get the motor running, though sometimes they will go (probably at lower speed/power) if you can spin the shaft. And amusingly, they may fail to a wrong value and allow the motor to run backwards.
A: I believe you are looking at replacing a 35/3 with a 35/5 MFD capacitor and this will in all probability be OK. I would not hesitate to use the 35/5 if I could not find the 35/3.
While your AC will still work with a bad capacitor, it will struggle to function correctly. Eventually, the system will stop working altogether. Extended use can cause further damage internally. We recommend contacting a professional to handle the repairs so that you don't risk any damage to your air conditioning.
If its a transformer less power supply circuit, then the change in capacitance will change the out put current. However if its a smoothening capacitor for example put on a rectifier bridge or running a a DC motor, its possible to replace 4uf with 5uf, but its better to replace with a high capacitance capacitor.
Rules for Replacing Electrolytic Capacitors
Replace with exact type if available. Replace with capacitor that has the same capacitance (uF – microfarad) as the original. Replace with capacitor that has the same voltage rating or higher. Use higher temperature capacitors when possible (105c).
If your HVAC capacitor is bad, the motor will run at higher amplification, run backwards or stop running altogether. Investing in the health of your HVAC system will save you time and money including your HVAC tune-up in Sacramento.
In polarized capacitors, the positive terminal (often marked with a "+" symbol) connects to a higher potential (positive voltage) and the negative terminal (sometimes marked with a "-" or indicated by a shorter lead) connects to a lower potential (negative voltage).
A motor will not have an even magnetic field if an incorrect-sized capacitor is installed. This will cause the rotor to hesitate in uneven regions. This hesitation causes the motor to become noisy, increase energy consumption, decrease performance, and overheat.
The start capacitor provides an immediate electrical push to get the motor rotation started. Without a start capacitor when the voltage is applied, the motor would just hum. The start capacitor creates a current to voltage lag in the separate start windings of the motor.
A faulty capacitor – whether it's the wrong size, blown, or damaged – can be the root cause of your motor hum. Solution: Test and replace any faulty capacitors. Both the start and run capacitors are usually located on the exterior of the motor housing, often in dedicated metal or plastic casings.
A faulty capacitor typically prevents the fan motor from getting enough power to start or maintain operation. In some cases, you might hear the motor humming but see no movement. This occurs because capacitor failure leaves the motor without its needed power boost.
How to test a bad capacitor? Connect the multimeter probes to the capacitor and set it to capacitance mode. Then, take the value and compare it to the expected value of the capacitor. If it is within 10-20% it is good, if not, it is bad.
Paper and electrolytic capacitors are usually expressed in terms of uF (microfarads). Short forms for micro farad include uF, mfd, MFD, MF and UF. Mica capacitors are usually expressed in terms of pF (micromicrofarads) (picofarads). Short forms for micromicrofarads include pF, mmfd, MMFD, MMF, uuF and PF.
Let us consider what happens if a 2.25 µF capacitor in ceiling fan is replaced by 2.5 µF capacitor. 2.25 µF capacitor, taken with tolerance limits of 5%, comes closer to lower limit of 2.5 µF, but if this 2.5 µF has actual value on higher side, it will cause a deterioration in performance.
The capacitor shall be used under rated temperature. Example: 40/70/21 means the minimum allowable temperature is -40°C and the maximum permissible temperature is +70 °C. Higher temperatures will cause the expectation life of capacitor shorter and may cause the protection device inoperable.