> Most modern compressors and pumps use rotary motors to shove a fluid from A to B inside a chamber, but rotary motors can lose as much as 30 percent of their output when they're asked to convert their rotary motion into linear motion required by compressors and pumps. That conversion is done by a crankshaft and once a crankshaft is in the system you get some friction losses but more importantly you get diminished efficiency because you're only getting maximum shove force in the middle of the piston stroke. The start and end of the stroke are both dead points where zero force is available to do any useful work. In a compression task you really want the maximum force to be applied at the end of the stroke not the minimum force. Overcoming these inertia forces every time the motor starts up requires a big spike in power demand which can be as much as five times the motor's normal operating consumption.
> The technology that Magtor have been quietly developing for over a decade now is a magnetically driven linear motor that completely eliminates the need for a crankshaft and achieves far higher operating efficiency as a result. Here's how it works. A fixed electromagnet stator sits at the centre of the motor. On either side of that are magnetic plates that are connected to each other via a shaft that runs through the middle of the stator. That connection effectively turns the two magnetic plates into a single moving part. As a voltage is applied across the electromagnet its polarity attracts the magnetic plate at one end and repels the magnetic plate at the other end. But because it's an electromagnet its polarity is changing 50 or 60 times a second as a result of the alternating current flowing through the copper windings. [...]
> You also avoid that costly power spike at start up as well. Because there's negligible mechanical inertia to overcome, as soon as an electrical current is applied the movement caused by magnetic attraction and repulsion can get going instantaneously. And on top of all that, Magtor have developed a very smart additional element that optimizes the motive power provided by the magnetic flux of the system. [...] In this working example a magtopressor is connected to a five-litre tank of air. Magtor's tests have shown that their device, which is smaller and lighter than a traditional reciprocating piston air compressor, can pressurize a cylinder 38% faster while consuming 33% percent less electricity.
(emphasis added)