If the compressor side was bad, the compressor will also run hot. Using the wrong capacitor rating or a poor quality capacitor can adversely affect the operation of the motor, the compressor or an entire HVAC system. I replaced them and they blew after about 20 minutes. Small fan motors have a capacitor permanently connected to a second winding. It also rated by voltage classification from 370Vac and 440Vac.The sizing of rated is a critical part for running capacitor.If the wrong run capacitor is installed, the motor will not have an even magnetic field. Inspect the capacitor. I recently replaced both the capacitor and the contactor in one of our A/C units when it stopped blowing cold air, so I’ve documented the process to share with you here. Anyone have any solution. Testing the motor and capacitor should only be made after the electric motor circuit has been identified and turned OFF and Tagged. Fan motors can sometimes run even with a bad capacitor but hidden damage is still happening to the fan… Check the manufacturer’s recommendations for ensuring the right sized motor. Signs of a Bad Capacitor on a Gas Furnace Blower and What to Do. My Central A/C is starting to blow fuses. This can lead to spectacular results such as the capacitor exploding. Weak or bad capacitors can cause both blower motors and condenser fan motors to run slow. I replaced them and they blew after about 20 minutes. But if the air conditioner keeps trying to run with a bad capacitor, it can cause very serious damage to much more expensive parts. The part may click on start up or on shut down. It was able to spin very freely. If your condenser fan motor is running slow it could be a weak capacitor or a condenser fan motor where the bearings are dragging and the motor is on its way out. If the cord got hot then the motor windings are getting hot … If this continues, the motor will begin to grow hot and will eventually burn out, requiring that the entire motor be replaced. Overamping. I checked and the fan motor was very hot. If the capacitor isn’t holding the charge needed to run the blower, the blower may run slower and/or hotter. Higher amps mean more wattage and more wattage means more heat. After I spun the squirrel cage (no resistance), the motor started up OK a few times. Thank you for joining us. Electrolytic capacitors should not get too hot otherwise they'll have a tendency to vaporize the electrolyte. I meant to say where on the contactor does the black and white wires go I already put the browns on the capacitor thanks for all your support. Common Problems with Electric Motors and Capacitor Start Motors. Electric motor starting & run capacitor troubleshooting FAQs Questions & Answers about Electric Motor Start-Boost or Run Capacitors Capacitors are electric devices that get an electric motor running at start-up or that help keep a motor running once it has started. R.Ph. A motor with a bad starter capacitor may fail to start (but will hum when power is applied) or will start slowly. This can lead to a furnace motor problem; be sure to call your HVAC professional. Is the Fan Motor bad or is the Capacitor going bad? The Fan motor spins very freely. If no work has been done to it lately most likely the motor has gone bad. All other capacitors I've touched were always cool, even when used on a warm PCB. Thank you for joining us. Knowing that, you can use what you find in this Instructable to check your system and replace the capacitor even before it fails. The second type of capacitor, more commonly found in hvac units technicians come across, is constantly energized when the motor is running. Start capacitors. Trane condenser fan motor to A.O.Smith condenser fan motor. This is especially true for the compressor. Sometimes really bad caps can leak their electrolyte out of themselves too. A start capacitor stays in the circuit long enough to rapidly bring the motor up to a predetermined speed, which is usually about 75% of the full speed, and is then taken out of the circuit, often by a centrifugal switch that releases at that speed. Electrolytic capacitors only function correctly when hooked up with the correct polarity (higher voltage on the positive lead). The Condenser fan motor I removed from a Trane unit had four wires 1 black, 1red, 1brown and . The fuses are located in the A/C unit. It is called a run capacitor. sw. is working. Its one of those things that happen. They are 30 amp time delay fuses. Check the manufacturer’s recommendations for ensuring the right sized motor. Anyway, I noticed that the capacitors are getting hot. It came on and ran for about 20 minutes and then threw the breaker. A bad run capacitor deprives the motor of the full voltage it needs to operate correctly. One Speed Working on a Two-speed Motor. I was skeptical that it would be as easy as desoldering the blown capacitors with new parts, but in one evening I … © 2020 Endeavor Business Media, LLC. A faulty capacitor will not be able to hold the charge necessary to run the blower motor properly. Weak or bad capacitors can cause both blower motors and condenser fan motors to run slow. A defective run capacitor can cause the motor to run at a higher amperage. Unfortunately, I couldn't find capacitors of the same size, so the modem is now outside of its plastic case. A capacitor is used to energize a second-phase winding in the motor. Is the run capacitor important in starting the motor? Using the wrong capacitor rating or a poor quality capacitor can adversely affect the operation of the motor, the compressor or an entire HVAC system. Once a motor has a reduced speed, other issues begin to occur – an increase in overall system noise, greater energy consumption due to the motor’s inefficiency, and an increase in the overall temperature of the motor. Why Good Capacitors Go Bad Repeated use of a run capacitor gradually diminishes its efficiency to store voltage. This is especially true for the compressor. Weak or bad capacitors can also make the ventilation engines not working or working slowly. I checked and the fan motor was very hot. So I'm getting 45.5 °C on the cap of the capacitors. This extra power boost is supplied by a component called a run capacitor. These capacitors usually have capacitance values of over 70 µF. The motor run capacitor is an essential component in HVAC systems, but all capacitors are not created equal. 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