A furnace blower motor is one of the most important components in your gas or oil furnace. Consider that the purpose of gas furnace is to warm the home, and realize that it is the blower motor that actually takes that heat and directs it from the very isolated, insulated furnace and in to the actual home. If you’re having problems with the blower motor, you’re not only left wanting for heating in your home, but you’re wasting energy as any gas you burn and heat your furnace creates that isn’t actually channeled in to the house that needs it is pointless. Tip: A gas or oil furnace can be a matter of survival in cold winter areas. Try to do a maintenance check for this and other issues during the autumn months so you have time to respond and fix anything before you desperately need the heat. One of the most common problems is that the blower motor makes a humming sound. If this is the case, then the first thing you should do is turn off your motor and allow it to cool. When it has cooled down to a safe temperature, check the motor.

Like with many devices that are in motion regularly, the humming could be the result of something as simple as improper lubrication. To determine if this why your blower motor hums, try lubricating the motor but don’t overdo it. Then restart the blower motor and listen. If the hum persists, then so do you. When your furnace blower has warmed your house to the set temperature, it begins to run on a slower speed. This is a normal energy saving mechanism that the motor is supposed to employ. But if your blower motor slows down unusually and makes a humming sound when it has slowed down, it might be due to a fault in the capacitor and the motor. Check your motors amperage draw using a tool that reads electrical current such as a multi meter and then check the rating on the plate of your motor to see how much is required. If the draw is more than the required amount, it’s an indication that your motor is working extra hard just to work normally. You will have to replace the motor and the capacitor.

This problem in your blower motor may have been caused by dust and dirt in your filter. An unclean and blocked filter makes the motor work harder to push out air. Make sure you check and clean the filter regularly to avoid this kind of problem from recurring. If your furnace blower motor hums when it’s switched on but at the same time does not actually turn, the capacitor may be damaged. This problem of getting a humming noise along with little to no spinning is very common with motors that do not have good quality capacitors. You should replace the capacitor with a good one and the blower motor will work smoothly. Once again, this may initially trace back to a simple blocked filter. If your motor does not run even after replacing the capacitor, it is most likely that the unit overheated. You should reset the safety buttons located at the side of the unit. This is usually caused by the wrong adjustment of the pilot light of your blower. Readjusting it to an appropriate level should solve this issue.

If your gas burners are dirty, they will give out a low sound that may sound like something between a low rumble and a hum. Cleaning, adjusting or replacing them will make the irritating sound go away.Why is my wall buzzing?add freon to ac cost September 25, 2004   Subscribefry's portable ac unit The Tell-Tale Buzz, or: This Wall, It Vibrates? mounting ac unit sidewaysFor the last several weeks (nearly a month now), a buzzing/vibrating noise has been coming from the wall between my apartment and the next one, driving both me and my neighbor crazy. What on earth could be causing this? (more inside -- literally) I have many different AC adapters and power supplies for a variety of devices, ranging from small 5V/1A USB chargers to laptop power adapters and desktop PSUs.

However, I often hear a whining noise from some of these power supplies. This happens most often when they are not connected to a device or otherwise in use, and stop making noise when I connect a load to it such as by plugging in a device that is not fully charged. Why do some AC adapters and power supplies make this whining noise? Why do some not make this noise? Is there anything I can do to suppress it? power-supply noise charger community-faq-proposed Most power conversion devices contains coils, such as transformers or inductors. These components use electromagnetism to convert AC mains power to low-voltage DC power. The varying magnetic fields generated by these components can cause them to physically vibrate at high frequency, resulting in a high-pitched noise. Most modern AC adapters are switched-mode power supplies. The internal switching frequency of an SMPS is typically low when unloaded and increases with load up to a certain point depending on the design.

The no-load frequency is often low enough to be within the human hearing range. In addition, in low or no-load situations, the PWM used to regulate voltage at the inverter stage will be at a low duty cycle creating a "spikey" output profile which is more prone to causing vibration in coils, and the transformer itself will tend to vibrate as well (see Daniel R Hick's answer below for more details). Together, these can lead to audible noise especially in cheaper units which fail to suppress this noise. Under load, a properly functioning SMPS should operate at a frequency well above the human hearing range, typically 50 kHz or higher (although some older designs operate at 33 kHz). However, the same noise can occur under load with a poorly designed or defective power supply as the coils may vibrate under electrical stress at a subharmonic frequency. Coils used as inductors or transformers in other electronic devices, including those on motherboards, graphics cards, or other computer components, can also vibrate during operation.

As such, a defective device can generate audible coil whine during operation. This is why you sometimes see weird gobs of glue on coils inside electronic devices. The glue helps reduce the vibration and noise the coils generate during normal operation. It is entirely possible for users to apply glue onto coils using a glue gun to suppress coil whine, and people have successfully done so on their computer parts. However, you generally can't do this easily on small wall chargers of the sort you mentioned without risking damage to the charger or exposure to potentially dangerous voltages. Ultimately, a whining noise isn't necessarily a sign of trouble in cheaper wall chargers when little or no power is being drawn from them. However, a computer PSU or laptop charger that generates coil noise especially when under load may be defective and you may want to consider replacing it. More information on coil noise can be found in this Wikipedia article. A "switching" power supply (like virtually all modern computer power supplies) works by "rectifying" the incoming 120V 60Hz (in the US) AC power into DC (at around 170 volts), "filtering" with capacitors, then using a semiconductor circuit to "chop" the DC voltage around 1000 times a second to turn it back into crude AC. (What's referred to as a "square wave"

, vs the "sine wave" of ordinary AC.) This "chopped" voltage then runs through a transformer to produce the desired output voltages. The outputs are again rectified to DC and filtered, to produce the desired voltages for the computer. With this scheme, basic voltage regulation is performed by adjusting the "duty cycle" of the chopped voltage. When the power supply is lightly loaded the circuitry doesn't produce a nice symmetrical "square wave" but instead a series of narrow spikes, and that "spikey" waveform is more likely to produce annoying audible noise in the transformers and other components and is also more likely to produce "electrical noise" that you would, eg, hear in a nearby radio. Additionally, when a power supply is lightly loaded more of the magnetic field inside a transformer escapes to the case of the transformer and to surrounding components (since less is captured by the "secondary" coil of the transformer), and this "escaping" magnetic field is more apt to cause noise.

The transformers are created in part by gluing plates of metal together. The AC fields causes back and forth forces in the metal plates. As the transformer ages the plates begin to separate and allows for movement on the plates which vibrate causing the humming sound you hear. Is there anything I can do to suppress it? As they've already told you, glue, because glue adds damping to the vibrating coil, then the coil's stationary response gets smaller as well as the noise produced glue adds constraints to the coil, then the coil's (mechanical) fundamental frequency increases above your hearing capability. Another solution that wasn't mentioned (disclaimer: I haven't read ALL the comments...), and an environmental sound one! consists in unplugging the adapter (that's what I do all the time with the charger for my Nokia cellphone!) I came to this page as I bought a new Craftsman C3 19.2 V Li-ion battery / charger which started making that whining noise as I plugged in.