PC fan dies when blowing 80°C air - any ideas / remedies?
MJB
Posts: 1,235
Hi All,
for my new Propeller controlled solar air heaters (3*1 m black sheet metal insulated at back side, with 3 cm air gap covered with polycarbonate transparent doulbe layer sheets) I am using cheap China PC-fans (12V, PWM-able) as the blowers. Blowers sit at the top / hot side and blow the air into the room. At the bottom is a long slit (with moscito-net) where the air enters (so not good for blowing in the cold air).
After running for about a week two of them just stopped working.
I had max air temperatures of 80°C coming in for about an hour at noon, other times below usually 40-50°C (at 10°C outside temp at less than full sun).
The system is equipped with a load of DS18B20 1-wire temp sensors, H-bridges for the motorized air-flaps (running at 3V, about $2.5 from China/EBay) and drivers for the PC-fans.
Tachyon is the controller with Internet connection in preparation ...
Could the Hall-Sensors or the permanent magnets have problems at this temperatures?
When I connect the problem fans to 12V directly there is sometimes a little forward/backward movement, but not sufficient to start off.
Even at nominal currents of around 300mA.
Anybody tried something like this?
Any positive or negative experiences in running PC-fans at such high temperatures?
Those would be just ideal, size and cost wise.
thanks,
Markus
for my new Propeller controlled solar air heaters (3*1 m black sheet metal insulated at back side, with 3 cm air gap covered with polycarbonate transparent doulbe layer sheets) I am using cheap China PC-fans (12V, PWM-able) as the blowers. Blowers sit at the top / hot side and blow the air into the room. At the bottom is a long slit (with moscito-net) where the air enters (so not good for blowing in the cold air).
After running for about a week two of them just stopped working.
I had max air temperatures of 80°C coming in for about an hour at noon, other times below usually 40-50°C (at 10°C outside temp at less than full sun).
The system is equipped with a load of DS18B20 1-wire temp sensors, H-bridges for the motorized air-flaps (running at 3V, about $2.5 from China/EBay) and drivers for the PC-fans.
Tachyon is the controller with Internet connection in preparation ...
Could the Hall-Sensors or the permanent magnets have problems at this temperatures?
When I connect the problem fans to 12V directly there is sometimes a little forward/backward movement, but not sufficient to start off.
Even at nominal currents of around 300mA.
Anybody tried something like this?
Any positive or negative experiences in running PC-fans at such high temperatures?
Those would be just ideal, size and cost wise.
thanks,
Markus
Comments
Many of these have a magnetic bearing. Could that demagnetize with excess heat?
Looking as specs for some of the branded fans seems to have nothing about maximum temperature, except Sanyo Denki at 85 degrees tops.
http://www.sanyodenki.com/news/newslist/20141113_SanAce40-120_9gt.html