What does 50/60 Hertz mean?
Transformers that are designed to specifically run at 60 Hz can’t be run at 50 Hz or in some cases only with significant derating. Magnetic flux is proportional to frequency so a 50 Hz transformer has a core 20% larger to handle 20% more magnetic flux than a 60 Hz unit. A 50 Hz transformer will simply run cooler at 60 Hz given the proper voltage is applied. Transformers cannot change frequency, the primary frequency equals the secondary frequency.