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12v dc motor troubles

matt91

Oct 26, 2012
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Oct 26, 2012
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hey i am a newbie to electronics and am making a project that involes a 12v dc blower fan
Specs:
NMB
Model BG0903-B044-VTL
97mm x 33mm
12V
1.35A
Part Specifications
Product Type Blowers
Rated Voltage 12 (V)
Current 1.030 (A)
Air Flow 0.810 (m³/min)
Air Flow 28.60 (CFM)
Mass 210 (g)
Noise 54.5 (dB)
Static Pressure 342.0 (Pa)
Static Pressure 1.400 (H20)
Size 95.0 (mm)
Speed 3700 (min¹)
Thickness [L] 33.0 (mm)


i have wired it to a standard car 12v battery to test it out and it was hardly spinning at the rated 3700rpm and no where near the 54db noise,is there something needed to make it run better/faster,and also i am going to wire in a potentiometer how would i go about dojng this,cheers
 
Last edited:

Harald Kapp

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Nov 17, 2011
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On this page it is mentioned that this particular fan has an integrated thermistor (blue or green) for regulating the speed. It will slow down the fan if the air is cool and speed up the fan if the air is warm.
You can test this by warming the fan with a hor hairdryer. Does it speed up?
If so, you could disassemble the fan, remove the thermistor and reassemble the fan.

Since you want to include a potentiometer anyway, you could replace the thermistor by a suitable potentiometer. You will have to find the correct value/range of resistance of the potentiometer by measuring the hot and cold thermistor. Of course, the potenetiometer will not fit within the fan, I'm referring to the connections only.

Harald
 
Last edited:

matt91

Oct 26, 2012
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i tried the hairdryer trick and it didnt seem to make any change to the speed of the fan,could it possibly be the battery im trying this on?
 

Harald Kapp

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No, a car battery can deliver way more power than the fan requires. I have no other idea. Can you see a thermistor?
 

matt91

Oct 26, 2012
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well looking down into the intake of the fan there is a blue blob sticking out is this what you mean
 

Harald Kapp

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Possible. I only read the reference on that linked website. I don't have that fan physically before me.
 

matt91

Oct 26, 2012
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sorry im new to this and knowing what things look like and there function and called is hard and still learning,so how would i go about removing the thermistor,
 

Harald Kapp

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I think you will have to disassemble the fan and find the connections to the NTC.
I have to admit that you risk ruining the fan as these are normally not made to be serviceable and re-assembly may not be easily possible.
 

itchyzombie

Nov 13, 2012
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Nov 13, 2012
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I have the same exact fan, click here for a video of me taking it apart.

There is a thermistor.

Yes, I'm a kid.
 
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