What Size Generator Do You Need to Run an Air Compressor? [Solved!]

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To power various tools job sites often require generators, especially when there is no power outlet available nearby. And when the brownfield has a large piece of equipment like an air compressor, the generator must be a powerful one.

And it begs the question, “what size generator do you need to run an air compressor?” Unfortunately, there is no simple answer to this question. There is a wide range of air compressors and each one has a different power rating.

Sizing a job site generator for an air compressor will depend on a number of factors, such as the wattage required to run and start the compressor, as well as the wattage required for the other tools you’ll use alongside the compressor.

There is a formula to determine all these numbers. In this article, we’ll go over each of them and help you choose a generator for your air compressor without going overboard.

Let’s get going!

What Size Generator Do You Need to Run an Air Compressor

Choosing the Right Size Generator to Run an Air Compressor

Generally you wouldn’t want a generator solely for the purpose of operating an air compressor, but rather one that is able to run other appliances in your workplace. Therefore going for a fixed size air compressor generator is a wrong concept, and you wouldn’t find such either in the market. It is best to choose a generator that exceeds the required wattage limit of your air compressor.

Air compressors come with various power ratings generally labelled as horsepower. Most of them are usually sold in the range between 0.5 to 6.5 HP. On the other hand generators are usually rated in Kilowatts (1 KW = 1000 watts).

So, in order to calculate the required power of an air compressor to be drawn from the generator, first you’ll need to convert Horsepower to Watts.

1 HP = 745.7 Watts

So, an air compressor rated for 2HP will draw approximately (2 x 745.7) = 1492 watts from the generator.

However, this is only the running or peak watts. You must also consider the additional wattage required to start the air compressor. The combination is referred to as the inrush current.

If you have an air compressor with a universal motor, the inrush current will be running watts multiplied by 2. The inrush current is significantly higher when the compressor uses capacitor start motors such as Type G or Type L. The inrush power for a Type G motor is three times the running watts, whereas a Type L motor requires six times the running watts at startup.

Therefore, to run a 2 HP air compressor with Type G motor, you need a generator that can provide at least 3,000 watts (1,492 x 2) of power. Usually, most air compressor manufacturers provide both their running and starting wattage, so you can simply add those to calculate the inrush.

That being said, it’s always best to err on the side of caution and get a generator that can produce more power than what is needed to run an air compressor. This will give you some wiggle room in case your generator is less efficient than expected or if you have other devices that you want to run alongside the air compressor.

For instance, if you want to run a miter saw alongside a 2 HP air compressor you’ll need to calculate the inrush current of that miter saw and add this to the compressor’s inrush. This will tell you the capacity your generator will need to have to run two devices at the same time.

If it uses 15 amps at 120 volts the power output required to run the tool will be, (15 x 120) watts or 1,800 watts. [amps x volts = watts]

However, the inrush current will be (1,800 x 2) watts or 3,600 watts. So, to run the two devices simultaneously the size of the generator needs to be at least, (3,000 + 3,600) = 6,600 watts. This method of adding the starting watts of all the devices when they are powered by a single generator to run simultaneously is called ‘Generous Wattage Calculation’.

Under the Conservative method, you simply add the starting wattage of the largest tool to the running wattages of all other tools you intend to run at the same time.

As you can see, a larger size generator with additional capacity will save you from buying another in such situations. Furthermore, a generator that only meets the power requirements of your tools will almost always be running at full capacity. This will put a lot of strain on it, potentially shortening its working life.

Calculating the Running Wattage Using Watts Formula

The horsepower (HP) rating is usually provided by your air compressor manufacturer. If you can’t find it you can use the watts formula to calculate the minimum generator size needed to run your air compressor.

There should be amperage and voltage information anywhere on your product nameplate or in the manual. You can also find them on your manufacturer’s website by searching with your specific air compressor model. Simply multiply these two numbers and you’ll get the running wattage.

Most home outlets are either 110 or 120V. If your air compressor is rated to draw 15 amps, the running wattage will be, (15 x 120) = 1,800. Add this number with the starting wattage and you’ll find the minimum capacity your generator needs to have to run the compressor successfully.

Note that air compressors with motors larger than 2 horsepower, will likely require a 240-volt source. Make sure you note these differences carefully and use a bigger size generator.

Bigger generators capable of powering 240-volts can still be used to power a 120-volt unit simply by flipping circuits. Small portable generators do not provide such advantages, though they are more effective for 120V household air compressors.

Running & Starting Wattages Of Different Air Compressors

Power RatingRunning WattsStarting Watts
0.5 HP10002000
1 HP15004500
1.5 HP22006000
2 HP28007700

0.5 HP is the smallest size air compressor. They are mostly found in home garages to deal with small home improvement projects and crafts. 1 HP air compressors are also used in home improvement and renovation projects, whereas 1.5 HPs are used in workshops to run small to medium-sized tools to use on cash washing, tire changing, etc. 2 HP is more powerful, hence a versatile air compressor. They are frequently seen on construction sites, where they handle powerful pneumatic applications.

Generator Safety Checklist

If you’re like most people, you probably don’t give much thought to your home’s generator until the power goes out. But if you have a generator, it’s important to keep it in good working order and to know how to use it safely. Here’s a checklist of things to do to make sure your generator is ready to go when you need it:

1. Read the manufacturer’s instructions carefully. This may seem obvious, but it’s important to familiarize yourself with your generator before using it. Make sure you understand how it works and what safety precautions you need to take.

2. Inspect the unit regularly. Check for any damage or leaks and make sure all the parts are in good working order. If something doesn’t look right, consult a qualified technician before using the generator.

3. Test the battery regularly and replace it if necessary. A weak battery can cause starting problems or unexpected shutdowns.

4. Change the oil and filter according to the manufacturer’s recommendations – more often if the generator is used frequently or for long periods of time. This will help keep the engine clean and running smoothly.

5. Keep the unit clean and dry. Dirt and moisture can damage sensitive parts and lead to corrosion over time. Wipe down the unit after each use and store it in a dry, well-ventilated area when not in use.

6. Use caution when refueling. Never add fuel while the engine is running or hot.

7. If possible, use an approved funnel or spill-proof container to avoid spills. Wipe up any spills immediately and dispose of them properly. Store fuel in a cool, dry place away from the generator. Check expiration dates on stored fuel and replace as needed.

8. Never fill fuel tanks more than 80% full to allow for expansion. Fumes from spilled gasoline can be explosive, so be extra careful when handling fuel near an open flame or spark. Always turn off the engine before refueling

9. When starting up the generator, do so slowly to avoid damaging the engine.

10. Make sure all electrical connections are secure and that any exposed wires are properly insulated.

11. Finally, never operate a generator in an enclosed space such as a garage – deadly carbon monoxide fumes can quickly build up to dangerous levels.

Air Compressor Risks That You Should Be Aware Of

An air compressor is a device that converts power (using an electric motor, diesel or gasoline engine, etc.) into pressurized air. The compressed air can be used to power pneumatic tools, blow up inflatables, or even act as a respiratory assistance device in the event of an emergency. While compressors are incredibly useful devices, they also come with a number of potential dangers that users should be aware of.

One of the most common dangers associated with air compressors is the risk of injury from flying debris. When using a compressor to power tools such as impact wrenches or jackhammers, bits of metal or other materials can break off and fly through the air at high speeds. These pieces of debris can easily cause serious injuries if they come into contact with someone’s skin or eyes.

For this reason, it’s important to always wear protective clothing and eyewear when using an air compressor. Another danger to be aware of is the risk of explosion. Air compressors work by compressing atmospheric air which contains a small amount of combustible gas (usually around 1-5%).

If the compression process is not done correctly, these gases can build up inside the compressor tank and eventually lead to an explosion. This is why it’s so important to follow the manufacturer’s instructions carefully when using an air compressor.

Finally, there is also a risk of fire when using an air compressor. This is usually caused by electrical faults within the compressor itself or by flammable liquids coming into contact with hot surfaces on the machine. To avoid this, always make sure that your compressor is properly grounded and keep any flammable liquids well away from it while in use. As you can see, there are a number of potential dangers associated with air compressors.

However, these risks can be easily avoided by following some simple safety precautions.

Air Compressor Safety Checklist

If you work with air compressors, it’s important to be aware of the potential safety hazards they present. Air compressors can cause serious injuries if they’re not used properly, so it’s important to follow some basic safety guidelines when working with them. Here are some air compressor safety tips to keep in mind:

1. Read the manual before using the air compressor. This will help you understand how to use the machine safely and avoid potential accidents.

2. Inspect the air compressor before each use. Make sure that there are no leaks in the hoses or connections. If you find a leak, repair it immediately. Also, check that the pressure gauge is working properly.

3. Wear proper clothing and personal protective equipment when using the air compressor. This includes eye protection, gloves, and earplugs or headphones to protect your hearing from the loud noise generated by the machine.

4. Don’t overfill the tank on your air compressor. This can lead to dangerous pressure build-up that could cause the tank to explode. Follow the manufacturer’s instructions for safe filling levels.

5. Disconnect the power source before performing any maintenance on your air compressor.


Will A 2000-Watt Generator Run An Air Compressor?

Given that a generator must cover the running and starting wattage of an air compressor, 2000 watts is just enough for those portable home versions. With that power rating, you could probably run up to 1HP air compressors safely.

What Size Generator Do I Need To Run A Pancake Air Compressor?

Most Pancake air compressors are 1 HP, and any 2000 to 3000 watt generator should suffice.

Final Words

If you’re looking to power an air compressor with a generator, you’ll need to know how much wattage the compressor needs in order to choose the right size generator. A small air compressor might only need a 3,000-watt generator. But a large air compressor could need as much as 10,000 watts or more.

Once you know how much power your air compressor requires, you can select a generator that can provide that amount of power. Be sure to choose a generator that has at least a bit of extra power so that it can handle any sudden surges that your compressor might create. To be safe, always check with the manufacturer of your air compressor to see what size generator they recommend.

When shopping for a generator, you’ll also want to consider the size of the unit and its fuel efficiency. Gasoline generators are usually more efficient and powerful than electric versions. Portable generators are a great option if you need to move your equipment around frequently.

We hope this blog post has given you all the information on the size of the generator you need to run for air compressors. Have a great day!

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