
The current draw of an air compressor can vary greatly, depending on various factors. The major factors affecting power consumption are power supply voltage, motor design, and operational load.
The motor design used in air compressors generally requires higher starting torque when under load than other motors. This increases the amount of current that is drawn as the motor starts up and reaches full speed.
The number of amperes is typically much higher during start-up than when running steady-state or unloaded. It’s important to note that each make and model vary widely concerning start-up amp draw; be sure to check your specific equipment requirements before powering up your system!
Finally, operational loading factors into how much power an air compressor draws to maintain demand throughout its cycle time.
Calculating the Amperage of an Air Compressor
Knowing the amperage of an air compressor is important when determining the size of the wiring that needs to be used to power the compressor. This will ensure that the compressor is operating safely and efficiently.
Determine the voltage of the air compressor
When calculating the amperage of an air compressor, it is crucial to first know what voltage the unit runs on. Knowing the voltage will allow you to properly determine the amperage your air compressor will draw. This information is usually noted somewhere on your unit. If not, consult your owner’s manual or contact your air compressor’s manufacturer for this information.
Amps = Watts/Voltage
For example, if your motor has a wattage of 700 and runs on 110 volts, 700 divided by 110 produces an amp draw of 6.36 amps (rounded up). Knowing this information can prevent damage or unnecessary strain be placed upon any wall outlet used in powering an air compressor meant for other voltages.
Calculate the wattage of the air compressor

The wattage of an air compressor is the amount of power that it draws to run. For example, a 5 HP compressor with a rated operating pressure of 125 psi has a wattage of 4,750 watts or 4.75 kW. To calculate the amperage of the compressor, divide the wattage by the voltage (in this case, 240 volts).
This gives you an amperage draw of 19.79 amps for a 5 HP air compressor with 125 psi rated operating pressure and 240 volts. It is important to check the rated load and voltage for your specific unit before attempting any electrical calculations as these can vary from model to model.
Convert wattage to amps
When you’re trying to calculate the amperage draw of an air compressor, one easy way is to convert the wattage into amps. Most compressors list their wattage, so it’s fairly straightforward to figure out the amperage draw. The first step is to get your power source.
- If you’re using regular AC household voltage, then you can calculate watts x volts = watts/amps. For example, if your power source is 220 volts and your compressor has 1,500 watts of power, then you will have 1,500 watts x 220 volts = 667.5 amps.
- If you are using a DC power source such as a battery or an inverter that converts AC voltage into DC voltage (such as 12V or 24V), then multiplication won’t work and you may need a volt-amp calculator instead. You simply enter the given information such as Watts and volts and press the calculate button for the calculation results in amps.
To calculate the amperage draw of an air compressor manually without any special tools handy, you can use Ohm’s Law: Voltage (V) = Current (I) multiplied by Resistance (R). it can also be thought of as Power divided by Voltage equals Amps i.e., 1500Watts/120Volts=12.5Amps
Safety Considerations

When using an air compressor, it is important to be aware of the power it draws. Air compressors generally draw between 15 and 30 amps, which can be extremely hazardous if not handled properly. It is important to understand how much power an air compressor draws, as well as other safety considerations when working with them.
Check the amperage rating of the circuit breaker
The power demands of an air compressor are determined by the CFM (cubic feet per minute) of air it requires to operate. It is important to remember that the required amperage for your air compressor is likely to exceed the amount indicated on the product’s documentation or label.
When calculating how many amps your compressor draws, be sure to factor in a safety margin. An undersized circuit will cause your breaker trips and result in an interruption of service.
When connecting your air compressor to a 220v outlet, you must take into account the amperage rating of the circuit breaker associated with that outlet. Otherwise, you risk tripping the breaker and disrupting power to other devices connected to that circuit.
It’s never wise to assume or guess at these numbers – instead, always follow manufacturers’ instructions for your specific model and refer for further assistance as needed.
Make sure the circuit is dedicated to the air compressor
To ensure the safety of you and your equipment, it is important to have a dedicated circuit installed for your air compressor. When determining what size circuit is needed to power an air compressor, the wattage or amperage requirements must first be determined.
Most air compressors are marked with a nameplate that states the amperes (or amps) and also may include the watts as well. To calculate the amount of current drawn in amps for an air compressor, divide the stated wattage by the voltage being used (in North America this would be 115V). For example:
- Amps = Watts/Volts
- Amps = 1500/115
- Amps = 13A
This means that a 15 amp rated circuit would be appropriate for an air compressor drawing 13 amps continuously. Additionally, you should always provide at least 25% more power supply than what is calculated. This will minimize tripped breakers and nuisance shutoffs during peak usage times.
Summary of how to calculate the amperage of an air compressor

To accurately calculate the amperage of an air compressor, it is important to have a few pieces of key information. Knowing the power rating of the motor, along with the voltage it operates at and the power factor (which varies depending on the type of compressor), will help you determine its electrical current draw.
Once these numbers are gathered, calculating an air compressor’s amperage is as simple as multiplying its motor HP by 746 and dividing that by the Voltage. This calculation yields the wattage, which can then be divided by 1.732 times the power factor to find amps.
If a 13 horsepower (HP) motor runs on 220 volts (V) and uses a 0.8 power factor, for example, then dividing 13 HP x 746 W by 220 V gives you 3420 watts (W). From there, divide that number by 1.732 times 0.8 to arrive at 19 amps (A).
Conclusion
In conclusion, it can be said that the number of amps an air compressor draws varies greatly depending on size and capabilities. A smaller, less powerful compressor may draw around 4-5 amps, while a larger, more powerful compressor may draw as much as 20 amps.
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