The "Swing Compressor
" built by Sawafuji Electric and used in the Engel and ARB products is an unusual design; most compressors have a more conventional electric motor and a compressor that's like an air compressor, presumably with a piston, connecting rod, and crank; the motor and compressor are sealed together in one housing.
The "swing" name
makes no sense to me, but the design
makes a lot of sense. While the description from Expedition Exchange as an "electrodynamic reciprocating device" is good, the common claim that it has only one moving part is not true, as is apparent from the illustrations posted by Engel USA: in addition to the coil/piston assembly, the entire mechanisim bounces on springs within the outer housing, and there are spring-loaded intake and exhaust valves. It is
I just guessed
that the Norcold compressor-based products - or at the least their motor/compressor - might be made by Sawafuji because of the shape of the compressor unit. I don't know one way or the other, but photos of the external design of Engel and Norcold portable units look identical to me.
The Norcold refrigerators with model names starting with "N" use a "gas absorption" cycle - not a compressor - as shown on their section of Thetford's Norcold Inc. Refrigerators
Similarly, Dometic sells huge numbers of gas-absorption-cycle refrigerators (the conventional RV design); only the models starting with "T" (from the original Tundra name) are compressor-based.