You will certainly have a decrease in power on the motor. You will also experience a shortened life (if it has enough power to run the compressor, it may not actually run, due to reduced torque). However, I believe it will run. However you will have the following issues. A motor designed to run at 60Hz will have reduced cooling when running at a slower 50 Hz. That same motor will probably draw more current as it was designed with an impedance match of 60Hz and not 50 Hz (this will be a compound problem as it pulls more current while running slower). So the motor will run hot, perhaps hot enough to fail very early. If it is a compressor for an air tank for a home owner, perhaps not a big deal ie it will run until it reaches pressure then shut off. You pump up tire, Compressor kicks on and off for a few times then doesn't run for hours or days (I would suggest to unplug when not in use), depending upon bleed off of pressure.
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If you are using professionally and run the system continuously, you may only get a few days (and maybe only a few hours) out of the system and experience nuisance trips on the thermal overload of the motor, making the system unbearable to use or just as likely catastrophic motor failure and you will have to replace the motor with the appropriate one. You should google the motor manufacture and look over the motor specs, perhaps this motor is dual rated (not likely, but worth a look).
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No transformer will help you, they are at a compatable voltage. A variable frequency drive would be your best solution if you definitely needed to keep the motor. However, a variable frequency drive is probably more expensive than replacing the motor with a correctly rated motor.