Most air cushion machines are decided on the bench, where the part is cheap to change, and then live with for years, where it is expensive to change, so it is worth being clear about what the voltage choice does and does not decide. It does not decide how much air the cushion needs. A cushion is a pressure and flow requirement against a porous deck, and the blower has to deliver that at the operating point, not at the free-air number on the datasheet. The voltage decides how that blower is fed, how it is wired back to the cabinet, and how much of the machine’s power supply has to exist at all.

My team supports OEM customers specifying brushless DC blowers for medical, industrial and laser equipment, and the air cushion question comes up constantly. This is how we work through it, using our own published blower data, with the caveat that every cushion is its own hydraulic problem and the bench numbers have to be re-checked on the actual table.

Start With the Air, Not the Volts

An air cushion machine holds a part on a film of air, and the blower must push air through a porous deck at a pressure the part does not slide on. The two numbers that matter are the flow the cushion consumes and the static pressure the deck needs, and electrical power follows from them: shaft power is broadly flow multiplied by pressure over efficiency. Until those numbers are fixed for your table size, part and workpiece mass, a 12 V against 24 V discussion is premature.

Our smallest brushless blower shows how published data should be read. The WS4540-12-NZ01 is a 48 mm 12 V DC brushless centrifugal blower with an internal controller, plastic blades in a PC housing on an NMB ball bearing, weighing 63 grams, published at a maximum 8 cubic metres per hour at zero pressure and 4.8 kPa maximum static pressure, with maximum air output at 3 kPa resistance and maximum efficiency at 3.5 kPa at full PWM. That last pair matters for a cushion: a blower is strongest in the middle of its curve, and a cushion working at full flow and zero pressure will disappoint you at the deck.

The sequence we recommend is simple. Size the cushion, read the flow and pressure off the deck, find the blower whose published P-Q curve covers that point with margin, and only then look at the voltage options. If a 24 V model covers your point and a 12 V model does not, the voltage question has answered itself.

What Actually Changes When You Double the Voltage

Moving the same blower family from 12 V to 24 V does not change the air, it changes the current, and current is where the consequences live.

• Current halves for the same power. Power is voltage times current, so doubling the supply voltage halves the current drawn at the same output. With the blower often at the end of a cable run under the table, that is the most useful consequence of the choice.
• Cable loss falls with the square of current. Resistance losses in the supply and return conductors scale with current squared, so a run that is comfortable at 24 V can be warm at 12 V for the same delivered power, which makes cable size part of the voltage decision.
• Voltage drop over distance falls. The same percentage drop happens at a higher voltage, which matters when the cabinet is several metres from the table and the cushion has to stay stable.
• Power supply topology changes. 24 V DC is the working voltage of industrial control systems, so sensors, solenoid valves and machine I/O usually already sit on it: a 24 V blower joins that bus, a 12 V blower asks for a conversion.
• Driver current ratings change. The published controller functions, speed regulation, speed pulse output, fast acceleration and braking, with over-current, under and over-voltage and stall protection, are what you actually specify, and they sit differently on 12 V and 24 V designs.

Two things people expect to change with voltage usually do not. Airflow and pressure do not, because they are set by the impeller geometry and the operating point. Nor does noise, which is set by the operating point, the housing and the installation; our published advice is to fill between the blower and the machine with foam or silicone, and to fit an inlet filter where the environment is dirty, neither of which changes with the supply voltage.

Where 24 V Wins on an Air Cushion Machine

24 V is the answer in most industrial air cushion builds, and the reason is current and available power, not the voltage label. Our 24 V catalogue covers what this application needs: the WS9070-24-S300 brushless centrifugal mini industrial blower, the WS9070A1 high pressure version, the WS8045-24-X200 with NMB ball bearing and three phase brushless motor, and the WS9290 series in 90 mm diameter for 24 V and 48 V. Where one mechanical design must cover several variants, the WS9260 platform is published as 12 and 24 V DC at 92 by 60 millimetres with airflow capacity above 100 cubic metres per hour, which makes voltage a build decision rather than a redesign.

The practical reasons to land on 24 V are the cable and the bus. A table fed from a cabinet over a long run is exactly the case where halving the current reduces the copper you buy, the loss you tolerate and the drop you design around. And when the cushion is large, the airflow requirement moves past what a small 48 mm unit can deliver, which is where the 90 mm and 92 mm platforms and the 48 V family come in.

Where 12 V Still Wins

There are three honest reasons to stay at 12 V, and none of them is that 24 V is too expensive.

• A light workpiece and a small cushion. If the table is small and the part light, the required flow and pressure may sit comfortably inside the published envelope of a compact 48 mm unit such as the WS4540-12-NZ01, with its 8 cubic metres per hour and 4.8 kPa figures, and there is no reason to buy a larger frame.
• An existing 12 V supply. If the machine already runs on 12 V, adding a converter to feed a 24 V blower is a cost and a failure mode you did not need.
• Integration fit. A blower that has to sit inside a plenum next to the deck has to be small enough, and at 48 mm and 63 grams the 12 V unit is easy to hide; a 90 mm platform is not, however good its curve is.

There is also the build variant argument in reverse: our catalogue carries high-speed brushless DC blowers with speed options across 12 and 24 V, so a machine family can share housing, driver and mounting and differ only in the supply, which is often the cheapest way to cover a small machine and a large one from one platform.

Five Questions That Settle the Choice

1. What flow and static pressure does the cushion need, and where on the P-Q curve does that sit? Take the answer from the deck, not from the free-air figure.
2. How far is the blower from the cabinet, and what cable is already in place? This is where current and drop become money.
3. What is already on the machine’s power bus? If it is 24 V, that decides most of the argument before the blower is chosen.
4. How much space is there inside the plenum, what is the duty cycle, and what compliance applies? A blower in a hot enclosure with a long MTTF rating still has a shortened life, because the published life figures are quoted at 20 to 25 degrees Celsius, and the machine around the blower carries the EMC, substance and, where relevant, medical device obligations.

How to Move From Specification to Sample

Most of these conversations end with a datasheet request rather than a catalogue order, and that is the right outcome. We design blowers and controller boards to a target performance, so the useful brief is the cushion specification: table size, workpiece mass, required flow, deck pressure, ambient temperature, duty cycle, available supply, cable length, noise limit and mounting envelope. From that we come back with the operating point, curve position and the variants that cover it.

Two practical notes save time later. First, fix the operating point rather than the peak: the maximum flow and maximum pressure figures on a datasheet are open-circuit conditions, and a cushion lives in the middle of the curve. Second, define the noise limit as a number at a stated distance, because “quiet” is not a specification.

Compliance sits on the finished machine rather than on the blower alone. In Europe the EMC Directive 2014/30/EU applies to the drive and controls, the RoHS Directive 2011/65/EU to substances and REACH (EC) No 1907/2006 to the supply chain; where the equipment is medical, IEC 60601-1 is the reference your customer will ask for. In the United States, the guarding requirements in 29 CFR 1910.212 apply to the finished build.

Frequently Asked Questions

Last verified: 2026-11-06. Model data comes from our own published product and category pages for the 12 V and 24 V brushless blower ranges, including the WS4540-12-NZ01 figures and the shared platforms. Air cushion performance depends on the deck, the workpiece and the operating point, so treat the published curves as a starting point and confirm on the bench. EMC, RoHS, REACH, IEC 60601-1 and US machine guarding requirements apply to the finished equipment and change over time, so confirm current obligations with your compliance adviser.