Quincy 4103D12VCB46M QT MAX - 10 HP, 120 Gallon Vertical, Two-Stage, 460V 3-Phase

A compressor rated to run continuously spends most of its life with nobody watching it. What matters then is not how well it starts but how reliably it stops. This QT MAX carries two independent shutdowns: a magnetic starter with thermal overload protection that drops the motor out before it can cook its own windings, and a low oil cut-off switch that halts the machine before a pump can run itself dry. They guard different failures, and either one can save the machine on its own.

Around them, a 10 HP motor on 460 Volt 3-phase supply, a splash-lubricated cast iron two-stage pump delivering 35 CFM at 175 PSI into a 120 gallon vertical ASME tank, rated for 100% duty cycle.

Two things to check before you order

The part number. The product title, the description heading and the specification block all read 4103D12VCB46M. The web address of this page, and one sentence in the current description, read 2103D12VCB46M. Both are printed here. Give us the code on your quote or purchase order and we will confirm the build with the manufacturer before it is made.

The automatic tank drain. Published details differ: the feature list and the description say an automatic electronic tank drain is fitted, while the specification field for the electronic drain valve says it is not. If an automatic drain is part of why you are buying this machine, ask us to confirm it in writing first.

The two shutdowns, and why both are needed

A magnetic starter is not a switch. It is a contactor with an overload relay that watches the current the motor is drawing, and drops it out when that current says the motor is in trouble - a stalled pump, a failed phase, a seized bearing. Without one, a struggling motor keeps drawing until something gives, and on a 460 Volt 3-phase machine the something is usually the windings. Quincy fits and wires the starter at the factory, so your installation is a supply run rather than a control panel build.

The low oil cut-off protects a different failure entirely. A motor overload relay knows nothing about oil level; it will happily keep a healthy motor turning a pump that has run its sump low. The cut-off switch monitors that directly and stops the machine before the bearings and rings are damaged. On a compressor that runs unattended for hours at a time, this is the shutdown that actually earns its keep - a slow leak or a missed service becomes a machine that stopped, not a machine that seized.

An oil sight glass is fitted alongside them, and it is worth using. Both cut-offs are last lines of defence; a five-second look at the glass before each shift is the first.

Why 460 Volt, and what the electrician needs

This is the build for a plant already running at 460 Volt. Higher supply voltage draws less current for the same shaft power, which generally means lighter conductors and a smaller feeder than the lower-voltage versions of the same machine.

How much smaller depends on your run and your code, which is exactly why Quincy publishes no breaker figure and instead records the requirement as consult a certified electrician. Settle the feeder, the disconnect and the protection before you order: this build is wired for one voltage and cannot be converted to another when it arrives.

Running slow on purpose

The QT MAX pump is geared to turn at a deliberately low speed for its output. Slower means cooler, cooler means the oil film survives, and a machine that runs cool is a machine that can hold a 100% duty rating honestly rather than on paper. It is also considerably less unpleasant to work beside than a small high-speed compressor labouring to keep up with the same demand. The cooling package supports the same aim - a finned intercooler between the stages, and an air-cooled aftercooler before the tank.

Will it fit

Vertical tank: about 40 inches by 30 inches of floor, roughly 75 inches tall, 1,000 lbs. Check ceiling height and the clearance of every door, shutter and overhead track on the route in. Level, solid concrete, with space around the machine so the coolers get moving air. Confirming the pad, the clearances and the access route before delivery is the customer responsibility.

Specifications

Perfect For

• Plants already on 460 Volt where matching the existing service avoids a transformer.
• Unattended or lights-out running, where the protective shutdowns are what stands between a fault and a replacement machine.
• Continuous-demand shops - blasting, finishing, production assembly - that need 35 CFM without a rest period.
• Maintenance teams who would rather find a stopped compressor than a seized one.

Wrong for a home workshop. No house has a 460 Volt 3-phase supply, and this is 1,000 lbs of industrial machine.

What Is In The Box

Delivered factory assembled: two-stage pump, motor, enclosed belt drive and guard mounted on the 120 gallon vertical tank, with magnetic starter, low oil cut-off switch, oil sight glass, intercooler and aftercooler in place. Warranty documentation ships with it.

You provide the electrical supply, disconnect and protection, pipework beyond the 1 inch tank outlet, any downstream filtration or drying, isolation pads and first-service consumables. No air dryer is fitted to this model.

Certification, stated honestly

The manufacturer certification record for this unit lists an ASME tank together with UL and CSA marks. Those describe the machine as it was built and tested.

They describe nothing about your site. No mark on a compressor certifies your feeder, your disconnect, your overcurrent protection or your ventilation against the code that applies where you are - that is your electrician work, confirmed by an inspector where a permit is required. If an insurer or an authority having jurisdiction needs the documentation, ask us before you order and we will obtain it from the manufacturer rather than leave you to discover a gap at commissioning.

Shipping and delivery

Freight only, to the lower 48 states. This item ships free, so there is nothing to add at checkout. Residential delivery carries a residential fee; a commercial address with a dock or forklift is cheaper, and terminal pickup cheaper again.

You must be able to unload it. The driver goes as far as the kerb. Getting 1,000 lbs off the trailer needs a forklift, a loading dock, or a terminal collection you have equipped yourself for.

Inspect before you sign. Walk the crate, look at the tank, the coolers, the pump and the motor, and write any damage onto the bill of lading before the driver leaves. Once a clean receipt is signed, a freight claim becomes an uphill argument.

Warranty

This unit carries a 1-year factory warranty, and Quincy makes it eligible for an extended 3-year term when the registration and maintenance conditions the manufacturer sets are met. Those conditions are the manufacturer to define and they change, so confirm the current requirements with us in writing before you rely on them.

The standing warning applies here as to any compressor: do not take the pump, the motor or the starter apart before the claim is raised. A dismantled unit is very difficult to warrant however plain the fault seemed. Call us first, keep every component, and photograph the condition you found.