Belt driven marine Reefer compressors

[THERMALBLAST]

Why are marine ac and reefer compressors always belt driven. what specific advantage is gained over direct motor coupled compressors

[RANGER1]

You can balance compressor to systems capacity by selecting different pulley sizes on electric motor .
You will get some slippage of belts causing inefficiency compared to direct drive .

[Brian_UK]

With a belt drive you will get some flexibility which may be required on board ship.

Boats flex.

[lowcool]

belt drives cope better with system losses and no cooling of windings required