Quote:
Originally posted by Schwartz
Cathar, I'm very interested in how quiet your blower is... I'm going to go WC but I'm having great difficulty choosing the Rad/fan combo. I don't really have space restrictions as the Rad/Pump/Res will be out of the case. I was originally looking for a heater core about the size of 2x120mm fans.
I'm curious if the noise from the blower is motor or air noise? If it's the motor, I'm guessing it could be damped further by enclosure?
Unfortunately, I also can't decide on the heater core since there is very little data on air flow capacity posted anywhere...
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My blower is quite large. 33x15x15cm in size. It looks much like Copyman's above.
It's installed in a large radiator box that helps to muffle the sound of it. The blower pretty much makes two noise types, that being the rushing air and the brushes in the DC motor. Incidentally the brushes are about 1/2" long rectangular blocks that are spring loaded. As they wear away the springs just keep pushing the brushes down. It'd take a long time for the brushes to wear away completely. I had to pull the blower apart and clean the brushes and contacts as the blower had been sitting on a shelf for 5 years and the oxidation of the copper over that time had left a thick black coating over the contacts such that the brushes were barely making any electrical contact. The noise of the brushes is a medium pitched low volume "whirring" sound, which gets completely muffled by the radiator box. The box however does amplify the inherent vibration of the blower and there is a very low pitched drone which changes in volume depending on the resonating pitch with the box's natural vibration frequency. Changing the voltage supplied to the fan by even a tiny amount is enough to almost totally nullify the effect of that noise.
The radiator box looks like this:
Except the back panel with the axial fans has been replaced by the blower. The blower takes up almost half of the back panel's area by itself.
I power the blower with a DC PSU which I can set to whatever voltage I choose, and it also allows me to keep an eye on its power draw. I typically have it set to draw about 25W, although I can put the blower to full speed (16V on my PSU) at which time it'll draw close to 250W of power and push around 750CFM of air-flow (in free-air rated mode). At the standard rated 13.6v it's rated for 650CFM of free-air flow. At the 25W setting I'd estimate it's pushing around a real 100CFM through the heater-cores, although I don't have anything to measure that with.