Your best bet is to use an optical tach, like mentioned above. One thing to watch out for, actually a couple, is the nameplate looks to be an English version for native speeds. The motor speed is dependant on frequency, 60 CPS in North America, 50 CPS in most of the rest of the world. It wouldn't vary that much, 3600 RPM vs 3000 RPM, but on such a machine it could be disruptive for smooth finishes.
The other point is the native motor is usually 1745~ RPM. Assure yourself that the replacement motor is the same, not 3450~ RPM.
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