In the Airbus A320, the overhead panel wiper selector knob has three settings: Off, Slow and Fast. At what speed do the wipers operate in Slow and Fast mode?
The A320's manual doesn't say—it doesn't have to as what is adjusted is the tension. Assuming you're asking out of curiosity and a general answer / other jet-liners would do:
It's measured in sweeps/strokes (or cycles) per minute – a cycle is two sweeps/strokes. Generally it's 250 sweeps per minute, and the slow mode is 2/3 of that (that's how the typical control system is designed).
This perfectly matches the numbers for the Boeing 737 (b737.org.uk) and Airbus A380 (technical training manual). Given the similarity between the 737 and A380, it should be similar if not exact. The optional intermittent option adds a delay between cycles.