50 Fans - One per wall outlet

[Abhiram Kanna]

What is the best way to setup 50 individual fans with individual on switches for each one, with all taking power from a wall outlet? This is very important and I really need help with this!!!!

[cluelessgenius]

depending on the wattage you need to consider the breaker layout in your house so you dont blow a fuse.

[Pixel5]

what kind of fan are we talking about here?

[YoFavRussian]

Are they all the same fans? What's the Voltage/Amp rating for the fans? You'll need 50 switches. And why are you doing this?

[mariushm]

Decide on the fan voltage. For example, are you gonna use 12v fans, are you gonna use 24v fans?

The voltage choice decides the power supply you're gonna use.

For 12v fans, you could use a regular ATX power supply.  You could also use a laptop adapter or a laptop adapter with 12v output. 

For 24v fans, you could use an industrial 24v power supply, or - as long as you don't mind fans spinning slightly slower than maximum speed - you could use 16.5v..19v laptop adapters.

You need to figure out how much power these fans will consume.  You can look on the label of the fan for that. For example, you may see 12v 0.3A as you can see in the picture below:

 

This means the fan should not consume more than 12v x 0.3A = 3.6w. So, for 50 fans, you would need a power supply that can produce minimum 50 x 3.6w = 180w , or multiple power supplies that in total can produce more at least this amount (for example 4 x 12v 65w laptop adapters or a single 300w+ ATX power supply)

However, keep in mind that for a second or so when the fan starts spinning from complete stop, the power consumption will be a bit higher, let's say 50% higher... so in the example above I would allocate minimum 5w for such a fan.

So, if I want to start all 50 fans from full stop at the same time, I would make sure to use a power supply that can provide minimum 50 fans x 5w = 250w ... a few seconds later when all fans rotate, the average power consumption would drop to the rated 3.6w or so.

Fans have two or more wires, up to 4 wires. First two wires are the plus and minus, voltage and ground. The third and fourth if they exist are optional. Third is rpm sensor (two pulses are sent to motherboard or fan controller or whatever each time a complete rotation is made) and the fourth wire is pwm - the motherboard can send a signal through this wire to adjust fan speed (if there's no signal received through this fourth wire, the fan assumes you want 100% fan speed all the time)

Now you need switches... you can use all kinds of switches, electronic distributors like Digikey, Mouser, Farnell/Newark have them.

 

You can have push buttons like you have on ball point pens (press for On, press again for off): https://www.digikey.com/short/phbphw

 

You can have rocker switches (like the on/off switch on power supplies) which give you a much better visual indication of On/Off : https://www.digikey.com/short/phbpbq

These have the benefit that you can punch rectangles in some metal sheet (aluminum, copper) and press fit these switches into the rectangles... easy.

Some of these are round so you can drill a hole easier :

You can have slide switches : https://www.digikey.com/short/phbp29

And so on ...... you connect the ground (-) of the fan to the ground of your power supply, and you connect the positive from the power supply to one pin of the switch and the positive of the fan to the other pin of the switch... when you switch to ON, you have voltage going into the fan....

 

If you like to play with Arduino or microcontrollers, you could have one tactile switch and one on/off status led for each fan:

 

You could also add a bunch of buttons that would basically do something like "Turn on or off this group of 8 or 10 fans at the same time" or you could press a button and then your Arduino could turn on each fan with half a second or 1s pause between each fan start so you won't stress the power supply.

You can use npn transistors or mosfets to control power for each fan  : https://itp.nyu.edu/physcomp/labs/motors-and-transistors/using-a-transistor-to-control-high-current-loads-with-an-arduino/

Lots of pins, but easy problem to solve using port expanders or shift register chips (or using multiplexing for button inputs) and led driver ICs for leds... a bunch of 8 channel led drivers chips can be chained together and controller with just two microcontroller pins.

If going with microcontroller, I would arrange the switches/buttons as a 8x8 = maximum 64 fans and on/off status leds.