there are two types variable capacity compressors on domestic fridges: variable frequency (tree phase motor controlled by VFD- all three terminals have same resistance), and variable voltage, called linear compressors, because there no motor, only resonance vibrator(only two terminals have 10Ohm resistance). the linear compressors have fixed frequency like 53Hz, 56.5Hz, or 60Hz . you cant put compressor with different frequency. about LG linear compressor refrigerator- it very complicated and very smart device, but made from poor components and materials. if you replacing compressor, replace the condensation heating loop, and use vacuum gauge, during evacuation, to make sure no moisture in the system. yes you can put any compressor same capacity instead of linear, but you will have trouble led on the control board flashing three times, but the front display do not indicate any problems, and all systems defrost, ice,.. will works fine. connect new compressor directly to board power input in series with low pressure switch set to -10"Hg. if your compressor have PTC starting components, or 3-in -one, you must add 5 minutes compressor delay relay, rated for start current, because if controller closes 3-way valve to pump down evaporators, the compressor goes into deep vacuum, and restarts shortly, after 3 way valve opens.