Cast Air 15 HP 460V 3-Phase Rotary Screw Air Compressor — 58 CFM at 100 PSI, 120-Gallon Horizontal Tank
This is the unit you look at when your 10HP compressor can no longer keep up. The Cast Air R15312HG30-460 is a 15 horsepower rotary screw compressor running on 460V 3-phase power, delivering 58 CFM at 100 PSI with a 120-gallon horizontal storage tank. It is built for production environments where air demand is continuous and downtime is not an option.
The 460V voltage rating matters for installation planning. At 460V 3-phase, the amperage draw is roughly half what a 230V unit of the same horsepower requires. That means smaller wire runs, lighter breaker sizing, and less heat in your electrical panel. If your facility already has 460V 3-phase service — common in shops that run CNC equipment, large lifts, or industrial spray booths — this unit integrates without an electrician having to upsize your panel.
Performance: What 58 CFM Actually Gets You
- Dual spray guns simultaneously: A high-volume low-pressure (HVLP) spray gun typically draws 12–18 CFM at the gun. Two painters working at the same time puts you at 24–36 CFM. This unit has 22+ CFM of headroom above that at 100 PSI.
- Impact wrenches: A 1/2" impact draws 4–5 CFM. A 3/4" or 1" impact draws 7–12 CFM. At 58 CFM, you can run three or four impact wrenches simultaneously with air to spare for other tooling.
- Air-powered lifts and tools together: Running an air-powered two-post lift (typically 10–20 CFM while raising/lowering) alongside active tool use is feasible with this output. The 120-gallon tank provides buffer storage so short peaks don't cause pressure drops.
- Sustained operation: Rotary screw compressors are designed for 100% duty cycle. Unlike reciprocating (piston) compressors that need rest cycles, this unit can run continuously without overheating or premature wear.
120-Gallon Horizontal Tank Configuration
- Storage capacity: 120 gallons of compressed air at system pressure. Larger tank volume means the compressor cycles less frequently and handles short burst demand from multiple tools without hunting for pressure.
- Horizontal orientation: The horizontal tank sits low to the ground with a stable footprint. Plumbing connections on a horizontal tank are typically more accessible — you can tap drain valves, supply lines, and secondary drops along the tank length without working at height.
- Floor mounting: The horizontal configuration gives you a lower center of gravity. Less concern about stability in environments with fork traffic or floor vibration.
- Condensate drainage: Horizontal tanks accumulate condensate along the bottom of the tank. A properly positioned auto-drain or manual drain valve addresses this. Install at the lowest point of the tank end.
Rotary Screw Technology vs. Piston Compressors
- Continuous duty: Rotary screw units compress air through two interlocking helical rotors. There are no pistons, no connecting rods, no valve plates wearing out. Designed for continuous operation at rated output.
- Lower noise: Rotary screw compressors run significantly quieter than reciprocating units of the same output. Important in shop environments where communication and phone calls happen near the compressor.
- Oil-injected cooling: Oil circulates through the compression chamber, cooling the rotors and sealing rotor clearances. This keeps discharge temperatures low and extends component life. The oil is separated from the compressed air before it reaches your tools.
- Maintenance interval: Routine maintenance on rotary screw units is typically oil changes, oil filter replacement, air/oil separator element, and intake filter — at intervals specified in the service manual. Not the daily oiling and ring inspection cycles of a piston unit.
Where This Unit Fits in the Lineup
- Below this (10HP range): A 10HP rotary screw delivers approximately 35–42 CFM at 100 PSI. If your shop consistently runs at 70–80% of that capacity, you are a cycle or two away from pressure-related slowdowns during peak demand. That's when the 15HP is the right step up.
- This unit (15HP, 58 CFM): R15312HG30-460. Production body shops, fleet service facilities with multiple bays active simultaneously, shops running spray painting alongside heavy tool use.
- Above this (20HP+): If you are running a full collision center with a dedicated prep area, paint booth, and multiple active bays simultaneously, or if you have frame equipment and alignment racks pulling air at the same time, 20HP and above becomes the appropriate range.
- 230V version: The R15312HG30-230 is the same unit wired for 230V 3-phase. Choose based on your available shop voltage. If you have both services available, 460V is generally the better choice for reduced wire and breaker sizing at this horsepower level.
Installation Considerations
- Electrical service: 460V 3-phase is required. Confirm your panel has the correct voltage and available amperage before ordering. Consult a licensed electrician for the final circuit sizing based on your specific run length and local code requirements.
- Ventilation: Rotary screw compressors generate heat. The compressor room needs adequate airflow — typically the unit specification will call out minimum cubic feet per minute of room air exchange. Inadequate ventilation causes thermal shutdown and shortened component life.
- Air line plumbing: At 58 CFM output, use appropriately sized supply lines. Undersized piping creates pressure drop between the compressor and your tools. General guideline: 3/4" or 1" supply main for runs under 100 feet at this CFM level.
- Condensate management: Run a refrigerated air dryer downstream of the compressor if you are painting or running air tools sensitive to moisture. A desiccant dryer may be appropriate for paint work demanding very low dew points.
Additional Specifications
Detailed specifications including exact motor frame, discharge temperature, oil capacity, inlet size, full-load amps at 460V, weight, and exact footprint dimensions are available on request. Contact us with your application details and we can provide the complete spec sheet.
Why Buy From OEM Diagnostic Tools?
- Specialist since 2016: We focus on professional shop equipment. We know the product lines, the installation requirements, and the real-world performance of the units we sell.
- Free shipping: This unit ships free to commercial addresses in the continental US.
- Free tech support: Call us at 866-217-0063 before and after your purchase. We can help you size your electrical service, plan your air distribution, and troubleshoot issues after installation.
- Full manufacturer warranty: Backed by Cast Air's warranty. We handle the process if you have a warranty claim.
- Honest guidance: If the 15HP is more than you need, we'll tell you. If your application needs 20HP, we'll tell you that too. We'd rather you order the right unit than the wrong one.
Call 866-217-0063 for quick answers and help!
Frequently Asked Questions
What is the duty cycle on the R15312HG30-460, and how does that compare to a reciprocating piston compressor?
The R15312HG30-460 is rated for 100% continuous duty — it can run indefinitely without a mandatory cool-down period. A piston compressor typically runs at 60–75% duty cycle, meaning it needs to rest roughly 15–24 minutes out of every hour under sustained load. If your shop runs air tools, lifts, or spray equipment for extended shifts, the rotary screw design on this unit eliminates the production interruptions and heat buildup that come with reciprocating machines at that workload.
What CFM output does this unit produce, and what tools or equipment can it support simultaneously?
The R15312HG30-460 delivers approximately 50–54 CFM at 125 PSI from its 15 HP Cast Air rotary screw end. That output is sufficient to run multiple impact wrenches, a continuous-duty sandblast cabinet, plasma cutter air supply, or several DA sanders at the same time — depending on individual tool demand. For reference, a 1/2" impact wrench typically draws 4–5 CFM, so this unit has enough headroom to serve a busy multi-bay shop or light production line without pressure drop issues.
What electrical service does the R15312HG30-460 require, and what breaker size do I need?
This unit runs on 460V, 3-phase power and draws approximately 21–23 FLA (full load amps) at that voltage. NEC requires a disconnect and breaker sized at 125% of FLA for motor branch circuits, so you'll want a 30-amp breaker minimum — verify with your electrician against your local code and actual wire run length. The 460V configuration is the most efficient option for 3-phase installs; it reduces current draw and allows smaller wire gauge compared to a 208/230V 3-phase setup at the same horsepower.
What are the oil change intervals for the rotary screw end on this Cast Air unit?
Cast Air rotary screw compressors use compressor-grade synthetic lubricant with a typical service interval of 2,000–4,000 hours depending on operating environment — dusty or hot conditions call for the shorter interval. The R15312HG30-460 also has a coalescing separator element that should be inspected at each oil change and replaced when differential pressure across the separator exceeds 8–10 PSI. Unlike a piston compressor where you're draining a crankcase every few months, rotary screw oil maintenance is hours-based, so logging runtime on your motor is the most reliable way to stay on schedule.
How loud is the R15312HG30-460 in a shop environment, and is it safe to run near work areas?
Cast Air rotary screw units in this class typically operate at 68–72 dB(A) at one meter — significantly quieter than a comparable reciprocating piston compressor, which often runs 85–90 dB. That puts it well below OSHA's 8-hour TWA threshold of 90 dB, and in many shops it's quiet enough to carry a conversation nearby without shouting. If you have questions about installation placement or want to confirm specs for your specific facility layout, call us at 866-217-0063 — we're Air Compressor Factory Direct, an authorized Cast Air dealer, and can help you spec the right setup.
