Fan with 0,36 A only draw 0,11 A


 
P

Patrick Eggel

New member
Hello Community,

I upgraded the fan from a 6.7 CFM 12 V 0.12 A ........to............ a 15 CFM 12 V 0.36 A.
My problem is that the 0.36 A Fan only draws 0.11 A on 100% speed. Could someone explain me why its not near 0.36 A?


Thanks in advance

Edit: The power supply supports up to 4A
 
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0.36a is the max amp draw. Not the constant amp draw. This amp draw will occur normally at the maximum amount of airflow with the least air flow resistance.

Add enough air flow resistance and the amp draw would get less. It's moving less air and doing less work.

Do you have a fan curve for the fan in question?

One thing you need to remember is that the fan does not perform according to it's nameplate. It performs along it's fan curve and performs according to the system it is placed in. IE the fan reacts to the environment it is placed in and doesn't simply put out air according to the described performance.
 
Did you increase the size of any ductwork intake or venting capabilities of the smoker to account for double the air volume?
 
Jeff.Ro said:
0.36a is the max amp draw. Not the constant amp draw. This amp draw will occur normally at the maximum amount of airflow with the least air flow resistance.

Add enough air flow resistance and the amp draw would get less. It's moving less air and doing less work.

Do you have a fan curve for the fan in question?

One thing you need to remember is that the fan does not perform according to it's nameplate. It performs along it's fan curve and performs according to the system it is placed in. IE the fan reacts to the environment it is placed in and doesn't simply put out air according to the described performance.
Click to expand...
Thanks for the answer.

I tested it without mounting the fan to the smoker. So I didn't create any additional bottleneck..

Is it possible to push more air through a small pipe (20mm) by increasing the fan size? Thats the reason why I bought a bigger fan with more power.
 
You can get more air through a duct, sure, but at some point you can't do it with a fan. You move up to something like a turbocharger, air compressor, snailshell blower, jet engine, etc. You are more than doubling the amount of air you are trying to move without increasing the size of the ducting, so you may have problems.
 
Patrick Eggel said:
Thanks for the answer.

I tested it without mounting the fan to the smoker. So I didn't create any additional bottleneck..

Is it possible to push more air through a small pipe (20mm) by increasing the fan size? Thats the reason why I bought a bigger fan with more power.
Click to expand...

Generally as friction pressure drop is proportional to the square of the velocity.... If you wanted to double the amount of airflow, water flow, whatever..... In the same piping restrictions.....You would need four times the static pressure. So this can get hard to do particularly with these small fans. But it all depends on the fan curves. To get that higher static pressure either the speed has to increase or the diameter of the centrifugal fan has to increase (tip speed).

Another thing that greatly affects the amount of air needed is.... How much of your air is actually bypassing the coals? This makes a huge difference. A distributor network that feeds the air to the coals instead of allowing much of it to bypass it and just go out the vent makes it much more efficient with the smaller amount of air. Any air that doesn't contact the burning coals is just a heat sink... And can actually cool it instead of providing heating
 
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