How I can know the efficiency of a pulley system

Hello to all!!,  I’m wondering what’s the overall efficiency of a pulley systems to make a reduction of the motor’s RPM of a shredder machine if I have as reference a motor of 1500 W with 3490 RPM and a pulley system of 49 : 1, that allows having 71 RPM in the shaft. The pulley system has two two-inch and two 14-inch pulleys.

I read in some places that the overall efficiency of a gearbox is 90 %, Is that value valid for the system I mentioned to you?

Searching “efficiency of pulley drive”
Lots of good info and design guides out there such as https://www.grainger.com/content/supplylink-industrial-belts-save-energy
So it depends on your design. Handbooks provide the minimum pulley size and separation to avoid slippage.

Thanks for the resource!! 🙂