Motor on fan feels hot. I took apart two fans today to clean them. I noticed no problem withe

Question

I took apart two fans today to clean them. I noticed no problem withe Pelonis fan (both on stands), but the housing for the motor on the WindChaser fan was pretty warm to the touch. In this weather, both of them run nearly 24/7. My question is this: is it dangerous to use it when I'm not home? Will it overheat and catch on fire? Thank you. Diane