ALC60 too noisy fan

[magnus pihl]

Hi laserists,<P>I dislike the high fan noise of the ALC60. It is the original with "air-tunnel". When I use it to try out new animations, I run at minimum power. The fan speed is the same whatever I set the optical power to. The air temperature is 65 degrees. When I turn up the optical power it is over 90 degrees.<P>Can´t I reduce the fan speed (by a resistor or transistor) when I run it at low optical power?<P>It is so noisy and irritating when I have it in the same room. How do you ALC60 users solve this problem?<P>Vielen dank!<BR>Magnus

[rolf]

Hi Magnus,<P>The Fan is mostly a AC type, that means<BR>you cannot turn the speed down by a<BR>resistor or transistor.<BR>You have to replace the fan by a DC 12V<BR>or 24V type. Then you can regulate the<BR>fan speed like the fans in PC supplies.<BR>The fan must work in the high temp. of<BR>the air, you must check this in the<BR>spec. sheet of the fan !.<P><BR>Rolf<BR>

[thorsten]

Although i would not recommend you to slow down the fan, if you want do to so, you could use a "variac".<P>but i think even if it is running at half of the original speed the difference in the produced noice is not very high...<P>so better keep it running at full speed.<P>even if the air coming out of it isnt as hot as it is at full power, if you slow down the fan, the cathode may get to hot AND think of the fact, that the fan isnt just cooling down the tube but also the diode and a resistor in the main circuit...<P>Thorsten<BR>p.s. sorry for any mistakes, my english isnt very good

[wkulick]

I agree with the suggestions posted. If it is the original fan, the bearing might be starting to go [img]images/icons/frown.gif"%20border="0[/img]. I put a new Patriot PT2B3 on mine and I don't think the noise is unacceptable. <P>Since the majority of noise is flow noise, you can consider ducting the flow to another location or outside.