Unit is running still cooling however something smells like it's burning.
Most likely a loose electrical connection starting to melt the plastic around it or the wire insulation. Those can be pretty dangerous, they can short to ground, or arc, in some cases even start fires. I believe they are some of the most dangerous faults. I would shut down the unit and get it serviced.
Many things could be causing that, none of them are good.
Fear not, you will not smell a compressor as they are hermetic and have a overload protection device. Is the smell inside or out? Like Like ovivero said, problably wiring of some sort. or Ballast for the lighting. But check the fan motor on the condenser.
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