Hello, everybody,
I have a UPS with two identical fans connected in parallel. Because they are loud, I would like to replace them.
The UPS is an old online Riello Dialog Plus Rack 150.
The nominal voltage of all fans is 12V.
Each of the old fans draws max 2.5W.
Each of the new fans draws max 0.96W.
Old fan type: Sunon KDE1208PTB1
New fan type: be quiet Silent Wings 2 (BL060)
If I only connect the new fans, the UPS reports a serious error (beeps unhappily).
If I add one of the old fans in parallel to the two new fans, the error goes away.
I think this is because the UPS recognizes a power consumption of only about 2W instead of 5W.
It doesn't look like a temperature sensor triggers the error, because the UPS works fine with two new fans and one old fan (all connected in parallel), even if the old fan is physically outside of the case and not cooling anything.
Without load the fan voltage is about 8V. The fans accelerate as the load on the UPS increases (while operating on batteries). Hence I am assuming that fan speed is regulated in an analog way only by voltage, since there are only two wires (hence we can't talk about PWM).
I am thinking about connecting a resistor in parallel to the new fans.
An old fan has a measured resistance of 650 Ohm or 1320 Ohm, depending on the polarity.
Thank you very much.
I have a UPS with two identical fans connected in parallel. Because they are loud, I would like to replace them.
The UPS is an old online Riello Dialog Plus Rack 150.
The nominal voltage of all fans is 12V.
Each of the old fans draws max 2.5W.
Each of the new fans draws max 0.96W.
Old fan type: Sunon KDE1208PTB1
New fan type: be quiet Silent Wings 2 (BL060)
If I only connect the new fans, the UPS reports a serious error (beeps unhappily).
If I add one of the old fans in parallel to the two new fans, the error goes away.
I think this is because the UPS recognizes a power consumption of only about 2W instead of 5W.
It doesn't look like a temperature sensor triggers the error, because the UPS works fine with two new fans and one old fan (all connected in parallel), even if the old fan is physically outside of the case and not cooling anything.
Without load the fan voltage is about 8V. The fans accelerate as the load on the UPS increases (while operating on batteries). Hence I am assuming that fan speed is regulated in an analog way only by voltage, since there are only two wires (hence we can't talk about PWM).
I am thinking about connecting a resistor in parallel to the new fans.
- If this is a good idea, the question is how big this resistor should be.
- If not, how can I get the new fans to run wihtout triggering errors?
An old fan has a measured resistance of 650 Ohm or 1320 Ohm, depending on the polarity.
Thank you very much.