|
Some of these posts are very old and might contain outdated information. You may wish to search for newer posts instead.
|
psycho_bin_farma
Hobbyist




Registered: 04/20/07
Posts: 171
Last seen: 13 years, 2 months
|
How would I reduce the speed of a 12VAC 3AMP fan for my humidifier?
#7632816 - 11/13/07 09:39 PM (16 years, 2 months ago) |
|
|
Yea so my humidifier is a little powerful 
but i'd like to reduce the noise so it isn't over working itself.



This is probably a bit over 1/4 speed:
Then it thins out considerably at full speed:
Also looks cool at night :
I dont want to attach random power supplies that could burn out the fan. I'm thinking I'd have to put more than 12V in to burn it out. not 100% sure.
Edited by psycho_bin_farma (11/13/07 10:29 PM)
|
mycocurious
Mike O. Kuerias



Registered: 02/09/07
Posts: 1,265
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7632834 - 11/13/07 09:43 PM (16 years, 2 months ago) |
|
|
DC = rheostat from Radio Shack...
--------------------
Don't mistake my tone for a "matter-of-fact" attitude. I'm just presenting what I believe to be correct, until I'm corrected... - How Myco-Curious Prepares Coir & Compost Substrates - How Myco-Curious Builds A Bulk Humidifier - How Myco-Curious Builds An Automated Greenhouse ------------------------------------ figgusfiddus said: Keep in mind that inoculating or whatever in front of a flow hood won't help your bad substrate, your bad inoculant, your bad sterile procedure, etc. etc. etc. It's not a +3 flowhood of magic, it's just a tool.
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: mycocurious]
#7632867 - 11/13/07 09:48 PM (16 years, 2 months ago) |
|
|
I should think you'd be best off replacing the fan. Thanks to the flourishing computer modification business you have a lot of choice in that type of fan.
|
freepain
Stranger
Registered: 10/31/07
Posts: 29
Last seen: 13 years, 8 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: yepyepyep]
#7632918 - 11/13/07 09:56 PM (16 years, 2 months ago) |
|
|
If you have any electronics skill or know anyone you can cut the positive wire and solder a resistor between the wires.
Sorta like this http://crazylightlady.us/images/Img31.jpg
That will lower the voltage there for lowering the speed at which its running
This is all referring to the fan which i imagine is what is causing most of the noise.
|
psycho_bin_farma
Hobbyist




Registered: 04/20/07
Posts: 171
Last seen: 13 years, 2 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: freepain]
#7632941 - 11/13/07 10:00 PM (16 years, 2 months ago) |
|
|
Ah, thanks, that helps, I'll try putting a potentiometer between the two.
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: freepain]
#7632988 - 11/13/07 10:09 PM (16 years, 2 months ago) |
|
|
Quote:
freepain said: If you have any electronics skill or know anyone you can cut the positive wire and solder a resistor between the wires.
Sorta like this http://crazylightlady.us/images/Img31.jpg
That will lower the voltage there for lowering the speed at which its running
This is all referring to the fan which i imagine is what is causing most of the noise.
Thats an ok idea but unfortunately that is actually a decently hefty little fan. 2.5A @ 12V means putting a resistor inline is going to be a problem. A lot of power for a resistor to dissipate to make an effect.
That resistor you posted has a 1/4 or 1/2 watt rating. The image you posted is actually a joke. Its a very dangerous (but amusing) idea that should never be done.
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: yepyepyep]
#7633009 - 11/13/07 10:12 PM (16 years, 2 months ago) |
|
|
Psycho.. use the bottom calculator here. I don't think its going to be possible to achieve what you're doing this way though 
http://www.blackfiveservices.co.uk/fanspeedcalc.php?Voltage=12&Current=2.5&Target=7
|
freepain
Stranger
Registered: 10/31/07
Posts: 29
Last seen: 13 years, 8 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: yepyepyep]
#7633018 - 11/13/07 10:14 PM (16 years, 2 months ago) |
|
|
Very true that is very dangerous(i was just kinda using it as a example of what i was trying to get across). You could put a couple resistors inline to cause the voltage to go down. At my job we use this tek. for fans on teleprompter all the time given they are not that powerful but it theory it should still work to some extent.
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: freepain]
#7633059 - 11/13/07 10:22 PM (16 years, 2 months ago) |
|
|
Quote:
freepain said: Very true that is very dangerous(i was just kinda using it as a example of what i was trying to get across). You could put a couple resistors inline to cause the voltage to go down. At my job we use this tek. for fans on teleprompter all the time given they are not that powerful but it theory it should still work to some extent.
Yep, I only pointed out the danger incase someone here didn't know and tried it. I'm sure you know what is going on 
Unfortunately, according to the calculator I posted, to get down to a 7v drop he would need over 7 watts of dissipation. Even a 1V drop would require 2.3w
|
catbear
Stranger

Registered: 01/12/06
Posts: 46
Last seen: 16 years, 1 month
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: freepain]
#7633070 - 11/13/07 10:25 PM (16 years, 2 months ago) |
|
|
Putting the resistors in-line isn't a bad idea. Its actually a good idea. Its what a LOT of machines do. For electronics that require like .1 volts they put 2-3 resisters in there.
Just remember to put the resister in there facing the right way. (laughs at my horrible joke)
Its perfectly safe to put the resistors in there. THE ONLY thing thats COULD happen is you blow the resistor there by ruining its ability to dissipate the voltage making the van as powerful as it was before.
Just go to radioshake and get a 15 cents worth of resistors and solder them bitches in.
|
psycho_bin_farma
Hobbyist




Registered: 04/20/07
Posts: 171
Last seen: 13 years, 2 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: yepyepyep]
#7633073 - 11/13/07 10:26 PM (16 years, 2 months ago) |
|
|
Yea, I found that formula calculator earlier but since i dont want to buy anything, i think i'll step down to a smaller fan until i can get a variAC power supply.
BTW, i tried some potentiometers and they didnt really work. one burned. and when it did work it was either off or on.
|
catbear
Stranger

Registered: 01/12/06
Posts: 46
Last seen: 16 years, 1 month
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7633130 - 11/13/07 10:36 PM (16 years, 2 months ago) |
|
|
YOU CHEAPASS!! Haha sorry... the lil buggers are like 5 cents EACH.. seriously if not cheaper.. If you buy them in a card board container with plastic.. it might be 30.. Also its a lot more work installing a fan than getting some resistors and cutting a wire. stripping it.. soldering in 2 resistors.. what 5minutes compared to 10 minutes of work.. pfft your crazy
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: catbear]
#7633155 - 11/13/07 10:41 PM (16 years, 2 months ago) |
|
|
Quote:
catbear said: Putting the resistors in-line isn't a bad idea. Its actually a good idea. Its what a LOT of machines do. For electronics that require like .1 volts they put 2-3 resisters in there.
Just remember to put the resister in there facing the right way. (laughs at my horrible joke)
Its perfectly safe to put the resistors in there. THE ONLY thing thats COULD happen is you blow the resistor there by ruining its ability to dissipate the voltage making the van as powerful as it was before.
Just go to radioshake and get a 15 cents worth of resistors and solder them bitches in.
Its a good idea in most cases, this is a 30w DC fan, not your average 0.1w computer fan.
I've already presented the math as to why it is not a good idea and not suitable in this case. Yes, machines do step down power, of course. That being said, you don't design a machine to have a 7.3w power resistor in your circuit unless you absolutely have to
Just to make things clear, you can use 15c resistors. But obviously, with them being at best 1/2w resistors you need 15 of them in parallel to dissipate 7.3w.
I hope this helps and I'm not bagging your cavalier attitude, I'm just saying, its a waste of time in this particular case
|
psycho_bin_farma
Hobbyist




Registered: 04/20/07
Posts: 171
Last seen: 13 years, 2 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: catbear]
#7633160 - 11/13/07 10:42 PM (16 years, 2 months ago) |
|
|
well, the fan is destroyed so now i dont have much choice. im kinda upset tho, that was a kickass fan.
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7633178 - 11/13/07 10:45 PM (16 years, 2 months ago) |
|
|
Quote:
psycho_bin_farma said: well, the fan is destroyed so now i dont have much choice. im kinda upset tho, that was a kickass fan.
Destroyed? It didn't blow did it?
|
psycho_bin_farma
Hobbyist




Registered: 04/20/07
Posts: 171
Last seen: 13 years, 2 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: yepyepyep]
#7633192 - 11/13/07 10:49 PM (16 years, 2 months ago) |
|
|
i touched the wrong wires together for a second when i was experimenting with power supplies and it popped.
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7633213 - 11/13/07 10:53 PM (16 years, 2 months ago) |
|
|
I'm sorry to hear that, thats terrible. I doubt the fan will be very cheap to replace
|
RogerRabbit
Bans for Pleasure



Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 11 months, 3 days
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7633236 - 11/13/07 10:58 PM (16 years, 2 months ago) |
|
|
Next time, just run the 12 volt DC fan on 6 volts. Automotive battery chargers work well because they have a six or twelve volt switch. A 30 watt resistor would be huge. Actually, it would be less than 30 watts if a 5 ohm resistor was used in series with the motor, it would be 15 watt. However a 5 ohm, 15 watt resistor isn't exactly off the shelf stuff. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
|
psycho_bin_farma
Hobbyist




Registered: 04/20/07
Posts: 171
Last seen: 13 years, 2 months
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7633305 - 11/13/07 11:17 PM (16 years, 2 months ago) |
|
|
Well, suprisingly i had another 90mm fan. This was one 12V and .23 amps.
Very quiet and adequate fae for now i believe.

How do ya like it?
(*I bet I could have hooked up 24+ large tubs and grown lions mane in all of them with the old fan rofl*)
Edited by psycho_bin_farma (11/13/07 11:20 PM)
|
yepyepyep
Stranger
Registered: 09/05/07
Posts: 147
Last seen: 26 days, 8 hours
|
Re: How would I reduce the speed of a 12VAC 3AMP for my humidifier? [Re: psycho_bin_farma]
#7633359 - 11/13/07 11:36 PM (16 years, 2 months ago) |
|
|
Quote:
psycho_bin_farma said: Well, suprisingly i had another 90mm fan. This was one 12V and .23 amps.
Very quiet and adequate fae for now i believe.

How do ya like it?
(*I bet I could have hooked up 24+ large tubs and grown lions mane in all of them with the old fan rofl*)
Hah excellent.
I had a 0.8a 12v fan as an intake in my computer case (a server rack case) and it was way way too loud so I'll bet that was a howler.
|
|