Electronic – How does using a 60Hz device on a 50Hz supply affect it

Brushed universal motors are largely independent of AC frequency, and as you have heard, will also run on DC. Their maximum speed is normally way above any synchronous speed referenced to line frequency. In their construction, the phase angle between the rotor and stator fields is set by geometry, not line phase. This is also why they run at high speeds - they just don't care about the line frequency. This is ideal for appliances such as vacuum cleaners and tools such as routers and planers, which don't need to maintain constant speed under varying loads. On the down side, they are typically not very efficient at low speeds, but for an application where they can run fast, that's not a problem.

As long as you get the voltage right, you'll be fine.

Variable speed controllers will also work well.

Both your machines use transformers inside to create the required working voltage. Using transformers at 60Hz designed for 50Hz will be no problem. Using one at 50Hz when designed for 60Hz is more troublesome, as the max flux inside the core will be greater than designed.

So for you 60Hz 220-230V is fine. But the electronics inside that measure time were built for 50Hz, so at 60Hz they will run faster. Many electronic clocks use industry standard chips which can be set to either 50 or 60 Hz by soldering a certain pin to ground or not.

Use them, don't worry, just don't trust the clocks.