The Castair I10312VC3 is the 10-horsepower, 3-phase industrial compressor with a 120-gallon vertical tank and the slow-speed C3 pump configuration — the same core machine as the I10312VC3-S without the factory-mounted magnetic motor starter. If your shop already has a properly rated motor starter on your electrical panel, or if your electrician is sourcing and installing the starter separately as part of a larger service installation, this is the right version to order. The C3 pump runs at 570 RPM — substantially slower than standard pumps — and that slow speed is what makes these machines last.
Who Needs This Configuration
The I10312VC3 fits shops on 3-phase power that are handling their own electrical installation or already have starter infrastructure in place. Industrial facilities with existing MCC (motor control center) panels, shops with in-house electricians, and installations where the starter is being mounted remotely from the compressor all make sense for the non-starter version. You get the same C3 pump, the same 120-gallon ASME vertical tank, and the same 35.0 CFM at 175 PSI — just without the factory-wired starter box on the unit itself.
The C3 Pump — Why It Matters for Long-Term Reliability
- All cast iron construction — cylinders, heads, crankcase. Cast iron handles heat and wear better than aluminum alternatives for continuous-duty service.
- 570 RPM pump speed — running at roughly half the speed of a standard 900+ RPM pump means proportionally less wear per hour of operation. These pumps can run for many years with proper maintenance.
- Tapered roller bearings at both ends of the crankshaft — proper support for the thrust and radial loads generated by a reciprocating pump. Tapered roller bearings outlast ball bearings in this application.
- Steel connecting rods with automotive-type insert bearings — at crankshaft and wrist pin. Insert bearings are serviceable and replaceable without replacing the entire pump.
- Disc and spring valves — reliable under high-cycle commercial use and straightforward to service when replacement is needed.
- 4-ring pistons — better sealing and significantly less oil carry-over versus 2-ring designs on budget pumps.
- Centrifugal unloader — loadless motor starts every time. The motor never has to start against compressed air, which dramatically extends motor life.
Tank and Motor
- 120-gallon vertical ASME tank — powder coated with four legs. The vertical orientation gives you 120 gallons of air storage in a 44x30 inch floor footprint.
- ASME safety valve — properly rated and code-compliant.
- 1725 RPM industrial motor with 15% service factor minimum — designed for sustained heavy-duty operation.
- Metal belt guard, totally enclosed — debris protection and safety.
- Copper discharge tube or stainless-steel braided flex line — rated for continuous high-temperature service.
Model Lineup — 10HP 3-Phase Industrial Series
- I1038VC2-S — 80-gallon vertical, C2 pump (758 RPM), 35.0 CFM @175 PSI, with starter, 40x24x74 in., 770 lbs.
- I1038HC2-S — 80-gallon horizontal, C2 pump (758 RPM), 35.0 CFM @175 PSI, with starter, 64x20x46 in., 770 lbs.
- I10312VC2-S — 120-gallon vertical, C2 pump (758 RPM), 35.0 CFM @175 PSI, with starter, 44x30x75 in., 860 lbs.
- I10312HC2-S — 120-gallon horizontal, C2 pump (758 RPM), 35.0 CFM @175 PSI, with starter, 69x24x50 in., 860 lbs.
- I10312VC3 (this unit) — 120-gallon vertical, C3 pump (570 RPM), 35.0 CFM @175 PSI, no starter, 44x30x75 in., 1025 lbs.
- I10312VC3-S — Same as this unit with factory-mounted magnetic starter included.
- I10312HC3-S — 120-gallon horizontal, C3 pump (570 RPM), with starter, 69x24x50 in., 1025 lbs.
Technical Specifications
- Model Number: I10312VC3
- Horsepower: 10 HP
- Phase: 3-phase
- Tank Capacity: 120 gallons, vertical
- Pump RPM: 570
- CFM @ 0 PSI: 45.0
- CFM @ 175 PSI: 35.0
- Max Pressure: 175 PSI
- Dimensions (LxWxH): 44 x 30 x 75 inches
- Weight: 1,025 lbs
- Motor Speed: 1725 RPM
- Motor Service Factor: 15% minimum
- Tank Certification: ASME
- Magnetic Starter: Not included (order separately or source locally)
- Pump Configuration: C3
Why Buy From Air Compressor Factory Direct?
We have specialized in industrial air compressors since 2016. Call us before you order and we will confirm whether the with-starter or without-starter version is the right call for your installation — it is a common question and the answer depends on your electrical setup. Free shipping, free pre-sale technical support, and full manufacturer warranty on every unit.
Call 866-217-0063 for quick answers and help!
