The worst type of motor is a dead motor. A leading cause of why your pool pump motor has stopped working is a bad capacitor. This little barrel of metal and dielectric material are one of the first things to go bad on a pump motor. A bad capacitor turns your pump motor into a dumped motor in a split second
The good news is that a failed capacitor is a simple thing to diagnose and fix, even for a regular DIYer. The trick is finding the right pump motor capacitor. There are a couple of routes to getting the correct capacitor for your pool pump motor. Hopefully, this helps you to find a forever home for a lucky capacitor.
The Two Types of Capacitors
There are distinct types of pump motor capacitors. The silvery metal kinds are the run capacitor, and the black are the start capacitors. Their names can pretty much tell their duties in the operation of the motor. The start capacitor boosts the motor’s torque at start-up, getting the motor to speed then gets taken out of the circuit. The run capacitor maintains the amp and volt output to the motor windings at speed, ensuring it operates smoothly.
Symptoms of a bad capacitor
A bad start capacitor can cause your motor to be unable to start, making either a loud humming noise or no noise at all. A failed run capacitor will cause your motor to shut down erratically, flip your breaker, overheat (which will compromise the other electrical parts of the motor).
Where to find the capacitor?
Capacitors are found in one of two places on a motor: under the end cap next to the wire terminals or in the “hump.”
For Troubleshooting Tips, visit – How to Test a Pool Pump Capacitor
How to find your pump motor capacitor
Read the Jacket Ratings
Every capacitor, whether run or start, has its ratings marked on its capacitor’s barrel. If the ratings are legible, this is the easiest way to find your match. The important rating to match on your capacitor is the microfarad ratings and the voltage. Run capacitors have a microfarad rating ranging from 15 to 50 MFD, with a standard voltage for pool pump motors of 370. A start capacitor’s microfarads are rated in a range of 88/106 MFD or 124/149 MFD. Once you have your capacitor type and ratings figured out, you can pick your new start and run capacitors confidently.
Match by Motor Identification Number
If your capacitor has been scorched, melted, or faded due to time making the ratings illegible, the next best way to find your match is using your pump motor’s identification number.
A pool motor label should list a Part, Catalog, or Model number that identifies that specific design. Once you identify the motor, you can reference the corresponding motor parts page.
Steps to identifying your Motor
- Find the part, model, or catalog number on your motor label
- Input the model number into Inyo Pool’s search engine
- Review the motor results, making sure to confirm the motor’s Horsepower (HP,) Voltage (V,) Amps, Service Factor (SF,) and Frame (FR)
- Select the motor’s parts diagram under the parts heading on the product page
Match the motor model number to the capacitor listed on the corresponding motor parts chart.
If you have tried the above techniques to find your replacement capacitor but still cannot track it down, leave a comment below with the motor and capacitor information you have on hand.