Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 47 users online :: 4 registered, 0 hidden and 43 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

5v chamber fans?

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
Sponsored 
  • Author
    Message

5v chamber fans?

Unread postAuthor: Cy4ka » Thu Mar 07, 2013 12:05 pm

I saw they make a 5v version of brushless fans. Is there any adverse effect on the fan if I used a 9v bettert to run it faster?

My reasoning is that it's better to have more flow from running a 5v fan faster rpms at 9v than to have an underperforming 12v fan runninf at 9v.

Yeah I know I can just buy a 12v battery but... nah.
9's are cheaper and I don't want to mess with wiring two AA bateries with a 9v to get 12v.

So will the 5v fan burn out at 9v? It's not like it will be running constantly, just a few seconds at a time to mix air and propane.
  • 0


Cy4ka
Private
Private
 
Posts: 23
Joined: Wed Jan 23, 2013 7:07 pm
Reputation: 0

Unread postAuthor: natas » Sun Mar 24, 2013 5:19 pm

I would personally go for a 12v fan, with a mixing tube.

But i guess both solutions work, just make sure u mount the 5v fan so its easy to replace if u burn it with 9v :-), but its usually not a problem.
  • 0

To make dreams come true, u must wake up.

natas
Staff Sergeant
Staff Sergeant
 
Posts: 122
Joined: Mon Feb 27, 2012 6:02 pm
Reputation: 0

Unread postAuthor: jsefcik » Sun Mar 24, 2013 6:51 pm

I dont think it would matter , ive done it before my dad always told me the fan will draw what it needs, there isnt much amps coming out of the battery so it wont burn it up
  • 0


jsefcik
Brigadier General
Brigadier General
 
Posts: 1132
Joined: Tue Jun 07, 2011 10:11 am
Reputation: 0

Unread postAuthor: Zeus » Sun Mar 24, 2013 7:05 pm

If the motor's internal resistance is 1 ohm, then at 5v it'll draw 5 amps, at 9v it'll draw 9 amps. That's enough to shorten the lifespan by a fair amount, but for your uses, it won't matter much.
  • 0

/sarcasm, /hyperbole
User avatar
Zeus
Major General
Major General
 
Posts: 1422
Joined: Tue Oct 27, 2009 7:34 pm
Location: 'Straya, C*nt
Reputation: 2

Unread postAuthor: Technician1002 » Mon Mar 25, 2013 3:19 am

^^^^ This is true if the motor is not turning.. When the motor turns, the current drops well below the DC resistance current value. When the motor runs, it self generates some so the Back Electro Motive Force (EMF) reduces the current draw.

Most small fans are brushless with electronic commutation. The current is less of a problem than the overvoltage may damage the electronics in the motor.

Larger AC motors have a couple of currents stamped on the nameplate.. LRA (Locked Rotor Amps) which is what limits the surge current when power if first applied. Power first applied to a motor is when it is NOT turning. The Fuse or Circuit Breaker must be designed to handle this higher current. The other current is the RUN Amps, which is the normal current with the motor running under a normal load.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Cy4ka » Thu May 16, 2013 11:21 am

I got a 12v D brushless fan and wired two 9v batteries together on a pushbutton switch. It's been working so far, it's a large fan in a 4" chamber so it mixes the air well and fast. You aren't holding the button down for long periods of time. I think it will last as long as I need it to, it's not running constantly as if it would in a computer.

Do any of you forsee issues later down the road with it? Eventually the 18v will drop anyway as the life of the batteries drains and it will only get closer to the 12v intended power.

Yeah?
  • 0


Cy4ka
Private
Private
 
Posts: 23
Joined: Wed Jan 23, 2013 7:07 pm
Reputation: 0

Unread postAuthor: TedC » Thu May 30, 2013 7:15 pm

I like to use the LM2577 DC-DC Adjustable Step-up Power Converter Module - you can find them on eBay for just a few bucks.

I use it to run the fan on 3 or 4 AA batteries.

Really small - I put it in an altoid tin with fan and ignition safety switches.
  • 0

User avatar
TedC
Private
Private
 
Posts: 9
Joined: Wed May 29, 2013 3:33 pm
Location: Maine
Reputation: 0

Sponsored

Sponsor
 


Return to Combustion Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'