Quincy 5103DS12HCA46 QP Pro - 10 HP Horizontal Two-Stage Air Compressor, 460V 3-Phase

Two-stage compressors are sold on the phrase rather than the reason. The reason is a heat exchanger. Air leaves the first cylinder hot, and if it went straight into the second cylinder in that state the machine would waste much of its work compressing hot gas. So it passes through an intercooler first. On this QP Pro that is a high-efficiency fin-and-tube unit, with an electronically balanced fan-type cast iron flywheel deliberately shaped to blow cooling air across it, the intercooler and the heads.

That combination is what a two-stage machine is actually for. The rest: a 10 HP motor on 460 Volt 3-phase supply, a fully pressure-lubricated pump with cast iron cylinders and aluminum heads, and a 120 gallon horizontal receiver rated to 175 PSI.

The model code, first

Two codes exist for this machine in our records. The description heading and the specification block say 5103DS12HCA46; the page web address and a sentence of the current copy say 3103DS12HCA46. We are printing both instead of choosing. Give us the code that appears on your quote or purchase order and we will confirm the build with the manufacturer before it ships.

What interstage cooling really does

Compressing air heats it - that is unavoidable physics, not a design flaw. A single-stage compressor squeezes air the whole way in one movement, so it is fighting increasingly hot, increasingly stubborn gas by the end of the stroke. A two-stage machine does the job in two smaller steps and cools the air in between, which means the second cylinder starts with cool, dense air and does far less work to reach the same pressure.

The consequences are practical rather than theoretical. Lower discharge temperatures mean valves and gaskets live in a gentler environment, and valves are what fail first on a reciprocating pump. Cooler air also means water condenses in the tank rather than travelling into your shop pipework. And doing the same work with less heat is simply less energy per unit of air.

None of that happens automatically. It depends on the intercooler actually getting airflow, which is why the flywheel on this machine is cast as a fan and balanced electronically rather than merely cast round. It is also why the clearance around the machine on your floor is not a nicety - block the airflow and you have paid for a two-stage compressor and installed a hot one.

Pressure lubrication underneath

The bottom end is fed by an oil pump rather than by splash, so the crankshaft, bearings and rods get oil at pressure from the moment the motor turns rather than once the crankcase has wetted itself. Because the oil is pressurised it also passes through a spin-on filter, and an oil sight glass on the machine makes checking the level a glance rather than a task.

Airflow: a number we will not print

Our specification record holds a delivered-air figure for this pump at 175 PSI, stored without a unit beside it. We do not publish a performance figure we cannot verify in our own data, so it is absent here deliberately. Ask us and we will confirm it in writing for this exact build before you order.

Fitting it, and powering it

Horizontal format: roughly 78 inches long, 28 inches wide and 55 inches tall, 850 lbs. That low profile is the reason to choose this over the vertical version - under a mezzanine, beneath a low roof, along a wall - and the price is a strip of floor. Level, solid concrete, and genuine clearance on every side, because as above the cooling depends on it. Plan a straight route in through your door. Confirming the pad, the clearances and the access is the customer responsibility.

This build takes 460 Volt 3-phase supply, so it suits a plant already at that voltage; drawing less current for the same power generally means a lighter feeder than the lower-voltage versions. How much lighter is your electrician call - Quincy publishes no breaker size and records the requirement as consult a certified electrician, because conductor sizing follows your run length and your local code. Settle it before you order, because a machine wired for one voltage cannot be swapped to another on arrival.

Specifications

Perfect For

• Plants already wired at 460 Volt, where matching the service saves a transformer and its losses.
• Long-running applications where discharge temperature, not peak output, decides how long the valves last.
• Low-ceilinged industrial units that cannot take a vertical receiver.
• Operations watching energy cost, where doing the same work with less heat matters over a year.

Not a home-workshop machine: there is no 460 Volt 3-phase service in a house, and the installation is a planned electrical job.

What Is In The Box

Factory assembled: two-stage pump with its fin-and-tube intercooler and fan-type flywheel, motor, belt drive and guard, mounted on the 120 gallon horizontal tank, with magnetic starter, spin-on oil filter and sight glass fitted. Warranty documentation is supplied.

Not included: electrical supply, disconnect and protection; pipework beyond the 3/4 inch tank outlet; any downstream filtration or drying; isolation pads; and first-service oil and filter. This model has no aftercooler and no air dryer, so if you need dry air, budget for it separately.

Certification, stated honestly

The certification record Quincy publishes for this compressor lists an ASME tank together with UL and CSA marks. Those describe the equipment as built and tested by the manufacturer.

They describe nothing about the installation you will build around it. No mark on the machine certifies your feeder, your disconnect, your overcurrent protection or the ventilation of the room it stands in - your electrician determines that, and an inspector confirms it where a permit is required. If an insurer or an authority having jurisdiction requires documentary evidence, ask us before you order and we will obtain the manufacturer file for you.

Shipping and delivery

This machine ships by freight to the lower 48 states. The freight cost is quoted live at checkout from the ZIP code you enter, so what you see is priced to your address rather than averaged across the country. Residential delivery carries a residential fee; a commercial address with a dock or forklift is cheaper, and terminal pickup cheaper still.

You have to be able to take it off the truck. The driver comes as far as the kerb. Moving 850 lbs on a long frame needs a forklift, a dock, or a terminal collection you have equipped yourself for.

Inspect it before you sign. Walk the crate, look at the tank, the intercooler, the pump and the motor, and write any damage onto the bill of lading with the driver still there. A signed clean delivery receipt is what turns a straightforward claim into a difficult one.

Warranty

A 1-year factory warranty is supplied with this model. The Quincy warranty documentation that ships with the machine sets out what is covered and what registration is needed; ask us and we will send it before you commit.

If a fault appears, open the claim before you open the machine. A pump, motor or starter that has already been dismantled is very hard to warrant, however clear the cause seemed at the time. Call us first, keep every part, and photograph the condition you found them in.