This page is about your compressor power supply. Read this page for a better understanding of the power your compressor motor needs to operate correctly and how a compromised or reduced power supply will affect it. Understanding this may deflect a problem with your compressor in times to come.
Table of Contents
- How Many Amps Does a Compressor Draw?
- Compressor Power Supply Limitations
- FAQs (Frequently Asked Questions)
How Many Amps Does a Compressor Draw?
Most DIY compressor owners have 120 VAC (Volts alternating current) running to the outlets in their house, workshop, and garage.
Some of the power outlets (plugs) are connected to the breaker panel or fuse box with 15 air compressor amp draw fuses or breakers to protect the line. Some are connected to 20 amp fuses or breakers.
There are other fuses/breaker amperage’s in the panel, but most of those are specialty applications like for the stove or baseboard electric heaters. The 15 amp and 20 amp circuits are the ones that normally run to typical electric outlets and are your compressor power supply.
And that is the reason why the largest home compressor motor powered by a 120 AC power supply should be in the 1 – 1.5 HP size.
Depending on the efficiency of the electric motor on your compressor, it will “pull” about 4 air compressor amps per 1/3 HP.
It’s not rocket science to see that a 1 HP air compressor amp draw will be around 12 air compressor amperage of power, and a compressor motor just a little larger than 1 HP would exceed the capacity of the 15 amp breaker.
Compressor Power Supply Limitations
Despite what the compressor labels may claim, you cannot run a very large HP motor from a typical 120-volt household supply.
The compressor manufacturers do not know if you are going to be plugging your air compressor into a 15 amp fuse/breaker supply, or to a 20 amp supply. I expect then that they would tend to lean towards making sure that their compressors would start and run on the 15 amp supply, this being the average for most homeowners, thus limiting the compressor motor size.
A compressor is an inductive load device similar in operation to the refrigerator motor.
When the fridge compressor first comes on, any lights on the same electrical circuit will dim briefly because the fridge motor needs a power inrush to start to get it up to the designed speed. While the motor starting is happening, the fridge compressor motor sucks more current than at normal running speed, pulling power from anything else on the circuit.
Compressor motors have air compressor startup amps capacitors (an electrical storage device) to supply a quick boost of electricity when the motor tries to start. That is why your compressor motor will start for you even though the draw of that motor is very close to, or may even exceed, the load capacity of the circuit on startup.
Since your compressor can pull more power than a typical house current can supply on air compressor startup amps, and it needs the start capacitor to bridge that power gap, can you see why having other power-drawing devices on the same circuit as the compressor motor can lead to compressor motor starting problems?
That’s why one of the first checks for a compressor motor that will not start is to make sure the power supply to the compressor is clean.
You can also see why if you need a large compressor capacity to run your air equipment it is necessary to install a higher voltage and amperage line for the compressor. The next step up is 220 VAC.
Manufacturing plant compressors commonly run on 480 or 575 Volts, to provide enough energy for a compressor that is big enough to generate the compressed air flow required for those high-demand installations.
Please note that I am not an electrician and the information on this page has been gleaned from assorted sources.
If you wish to learn more about wattage, visit our Wattage Needed for 3.5 HP Air Compressor – How Many Watts Does a Compressor Use? guide!
FAQs (Frequently Asked Questions)
A 20-gallon air compressor usually draws around 15 amps, making it suitable for most 110-volt AC outlets.
The air compressor can use a cigarette lighter style plug. The maximum current draw for a small DC 12V air compressor is 20 to 30 Amps but it will tend to draw a lot less than this.
A 5 hp air compressor will draw around 21 amps.
Depending on the efficiency of the electric motor on your compressor, it will draw around 4 air compressor amps per 1/3 HP. Therefore, a 1 HP compressor motor will draw around 12 air compressor amperage of power.
If you have any questions regarding how many amps an air compressor uses, please leave a comment below, with a photo if applicable, so that someone can help you!