All that matters for electric motors is HP, voltage 1 or 3 phase, RPM and frame size.
HP; Same or larger
Voltage; If the original motor was 115/230 and you're using 115 volts then the replacement can be either 115/230 or just 115. 110, 115 and 120 are all the same. 220, 230 and 240 are all the same and the vast majority of these motors will work just fine on a 208 volt system.
1 or 3 phase; A 3 phase motor will not work with single phase power unless you have some sort of phase conversion equipment. A single phase motor will work on a 3 phase system provided the voltages are the same.
RPM; This needs to be close but not exact. If the original motor was 3450 RPM, a new one with 3300 to 3600 will work.
Frame size; The number (like 56) must match, with exceptions for 143 and larger. The letters in front of the number, if any, don't matter. The letters behind the numbers do matter. If the letter is C then it is designed to bolt directly to the equipment but if it has a base (some do, some don't) then it'll work the same as standard but it might look funny. If it's H then it has a non-standard mounting base. It might work, it might not. If it's Z, then it has a non-standard shaft. It might work, it m might not.
Cradle or rigid base doesn't matter. A cradle base will be slightly less noisy that a rigid one but in most cases it won't matter.
