- #1
DaveC426913
Gold Member
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OK, I've almost finished the hardware for my micro-aquarium.
See diagram
P=pump, H=heater, L=light (20W halogen), F=fan(CPU cooler)
The 12V system is my last tweak. The basis of it is one of those 3x20W puck light sets from IKEA. I've ditched two of the lights and wired up the fan instead. The transformer is rated at 12VAC 0.5A. The fan wants 12VDC 0.13A so there's a rectifier in there.
When wired up and running, I get 15V across the fan connectors.
My problem: the fan is running too fast and too loud for my liking. So I disconnected the capacitor. This way, I get only about 5.5V.
It drops the fan RPMs fine; the problem comes when the timer cycles the light/fan combo off and on again - there isn't enough juice to get the fan rotating again. It just vibrates.
What I'd like is something halfway between the two outputs. Quiet but with enough kick to get it started. 10VDC? Would it simply be a matter of putting a resistor in the fan circuit somewhere?
Also, the light/fan circuit has a faint, high-pitched whine when the timer's off. Is this bad/avoidable?
See diagram
P=pump, H=heater, L=light (20W halogen), F=fan(CPU cooler)
The 12V system is my last tweak. The basis of it is one of those 3x20W puck light sets from IKEA. I've ditched two of the lights and wired up the fan instead. The transformer is rated at 12VAC 0.5A. The fan wants 12VDC 0.13A so there's a rectifier in there.
When wired up and running, I get 15V across the fan connectors.
My problem: the fan is running too fast and too loud for my liking. So I disconnected the capacitor. This way, I get only about 5.5V.
It drops the fan RPMs fine; the problem comes when the timer cycles the light/fan combo off and on again - there isn't enough juice to get the fan rotating again. It just vibrates.
What I'd like is something halfway between the two outputs. Quiet but with enough kick to get it started. 10VDC? Would it simply be a matter of putting a resistor in the fan circuit somewhere?
Also, the light/fan circuit has a faint, high-pitched whine when the timer's off. Is this bad/avoidable?