The fan I am using is the stock fan that came with the 940.

The nominal voltage for these fans is 12 V, but what is their max? They run on as little as 4 V (very slowly), and I've taken it as high as 20 V, but I don't want to unknowingly damage the fan as it gets higher and higher. What's a good max for constant operation?

By the way, I'm using the fan in an external application, controlling it with an industrial power supply.