Plasma cutter air requirements: what size compressor you need
Published air needs for LOTOS, PrimeWeld, Hypertherm and other plasma cutters, in CFM at a stated pressure, and how to read a compressor label against them.
A plasma cutter needs two things from your garage: electricity and compressed air. Listings talk about the first and mumble about the second, and a compressor that cannot keep up is the most common reason a new cutter disappoints.
Compare two numbers that share a pressure: the air flow your cutter requires, in CFM at a stated PSI, and the air flow your compressor delivers at about that PSI. If the compressor’s figure is equal or higher, it can run the cutter continuously. Tank size only decides how long you can cut when it is lower.
What each maker publishes
Checked 2026-09-19 against each maker’s manual or product page. A flow figure without a pressure cannot be compared with a compressor label, so we mark it.
| Cutter | Air flow as published | Pressure setting as published | Filter or regulator |
|---|---|---|---|
| Hypertherm Powermax30 XP | 4 SCFM at 80 PSI recommended; 3.5 SCFM at 68 PSI minimum | Maximum inlet 135 PSI | Internal filter regulator |
| LOTOS LTP5505D | Compressor greater than 4.0 SCFM at 65 PSI | 65 PSI on 220 V, 50 PSI on 110 V | Front mounted, with gauge |
| LOTOS LTP5000D | 3.6 CFM at 65 PSI; compressor larger than 4.0 SCFM at 65 PSI | 60 to 70 PSI across the manual | External |
| PrimeWeld CUT50D and CUT50DP | 5 CFM at 80 PSI in the features list; “5 L/min” in the spec table | 40 to 65, 40 to 75 and 75 PSI in three places | Regulator included |
| ARCCAPTAIN CUT50 | Compressor of at least 90 PSI and 5 CFM | 30 to 75 PSI, or 40 to 70 recommended | Built in, with gauge |
| YesWelder CUT-55DS PLUS | 6.0 CFM or more, no pressure stated | 50 to 60 PSI on 110 V, 55 to 70 on 220 V (page); 45 to 75 (manual) | Rear mounted |
| YesWelder MCT-520 combo | 2.8 to 3.5 CFM, product page only | 45 to 70 PSI (page); 50 to 60 (setting chart) | Not stated |
| Bestarc BTC500DP | “150 L/min” printed in a row labelled CFM | 40 to 65 PSI (7GEN); ranges differ by generation | Built in on the newest version |
| ARCCAPTAIN MIG205MP combo | Not published | Two different maximums on consecutive manual pages | Not stated |
Only Hypertherm, LOTOS and PrimeWeld print a flow figure with its pressure. Sources are listed on best plasma cutters and best multiprocess welders.
Reading your compressor’s label
Look for a line such as “5.1 SCFM at 90 PSI”. That is the pump’s delivery: the air it can supply continuously at that pressure.
- Match the pressure before you compare. A compressor delivers more air at a lower pressure. A rating at 90 PSI is conservative against a cutter that wants its air at 65. A rating at 40 PSI tells you little about 80.
- SCFM and CFM are close enough for this purpose. SCFM is flow corrected to standard conditions. We print whichever the maker uses.
- Ignore horsepower and tank gallons as sizing figures. Horsepower is a marketing number on small compressors. The tank is a reservoir: a bigger one gives longer cuts from an undersized pump and longer waits afterward.
- Leave margin. A pump running flat out the whole time makes more heat and more water.
When the compressor is too small
You will see the cutter start cleanly, then the arc sputter, the cut widen and go ragged, and on some machines a low pressure light. Stop, let the tank refill and continue. It works for trimming and short cuts. It does not work for slicing a long piece of plate.
Wet air costs you consumables
Compressing air squeezes water out of it, and warm humid days make more. Water and compressor oil in the line erode the electrode and nozzle and roughen the cut. Drain the tank regularly, keep the filter bowl at the cutter empty, and run a length of hose so the air cools and drops its water before the final filter. How a cutter uses its air is explained in plasma cutters explained.
Then check the circuit
Air is half the question. A compressor and a plasma cutter running together are two large loads, and on 120 volts the cutters here that publish a figure list 38 to 45 amps of input by themselves. The compressor needs its own circuit. See welder amp draw for the arithmetic and can my panel handle a welder for what to gather before calling a licensed electrician.
Frequently asked questions
Can a pancake compressor run a plasma cutter?
For short cuts, often. Small compressors typically deliver less air than these cutters ask for, so the tank supplies the difference until it runs down, then the cut starves. Check the delivery figure on the compressor's label, in CFM or SCFM at a stated pressure, against the cutter's requirement. If the compressor's number is lower, expect to cut in short bursts and wait.
How many CFM does a plasma cutter need?
The makers that publish a flow figure for 50 amp class machines ask for roughly 4 to 6 CFM: LOTOS says more than 4.0 SCFM at 65 PSI, Hypertherm 4 SCFM at 80 PSI for its 30 amp machine, PrimeWeld 5 CFM at 80 PSI, ArcCaptain a compressor of at least 5 CFM at 90 PSI, and YesWelder 6.0 CFM or more with no pressure stated.
Do I need an air dryer for a plasma cutter?
You need dry, clean air, and how you get it depends on your climate and compressor. Most of these cutters include a filter regulator that traps some water and oil. In humid conditions a compressor makes a lot of water, and an extra filter or desiccant dryer near the cutter is common practice. Wet air shortens consumable life and roughens the cut, and makers say so in their manuals.
What pressure should I set?
The pressure your cutter's manual gives, measured at the cutter while air is flowing. Recommended settings here run from about 50 to 80 PSI, and they change with input voltage on some machines. Several makers print different ranges in different documents, so use the manual and start in the middle of its range.