Thinking of a new light ..

stardustsailor

Well-Known Member
Looks like digikey has new stock of 3k. Too bad they didn't get different bins or temps
I've already found 4 pieces of CXA 3070 3000K 80 CRI Z4 bin ..
I've to wait for the 2700 K 80 CRI ...
And for the drivers ...
(About two months ! )


For powering the fans ,I 've found a brand new ,unused meanwell PS-45-15 ( 15 VDC 3 A ) somewhere stashed amongst other electronic equip ...

Now ..
For controlling 4 HLP drivers simultaneously a 100K / N drivers pot should be used ....
That means that all Dim- & Dim + ,have to be connected parallel to a 25 K pot ..
Here in EU ,25K pot is way difficult to find ..
Instead there is the 22 K pot ,everywhere...

So a double 22K pot has to be used ....

For the led controlling part a 3K6 (3600 ohm ) resistor should be in series connected with pot ( start or wiper ) ...
22K + 3K6 = 25K6 ...
That will give the 100 % output of 1950mA ....

At minimum set ,there's the 3K6 resistor ,acting as 'thresholder' ...
For 4 drivers is like what a 14K4 resistor( 4 * 3.6 ) would have been for a single driver ...
That means the minimum setting is at 14.4% of the 1950 mA max setting ..
Controlling range of all four drivers ,with one single 22K pot and a 3K6 resistor in series ,output current range would be : 280 mA(min) - 1950 mA (max)

As for the pwm fan controlling circuit ,from 100K pot and 47 nF cap setting a pwm freq of ~300Hz ( 1.44 / (100000 * 0.000000047 )= 306.38 Hz ),
now pot has changed to 22 K .... 4 times smaller pot ,needs 4 times bigger cap ,for the freq to stay same ...
So 1.44 /( 22000* 0.00000022)=297.52 Hz ...
With a 22K pot ,a 220 n cap has to be used for the pwm freq to stay around 300Hz ( stable operation / non audible sounds from fan )
 

Bueno Time

Well-Known Member
Nice project you've got going.

I am interested in the pwm controller for your fans. I have a 4 wire 120mm fan exhausting my veg tent right now and I just have the blue wire hooked up to a toggle switch to ground with the black fan ground wire, so it is operating at low speed with the switch on. It is too loud at full speed but I know I could get a lot more cfm out of it if I could pwm the blue wire to ground.

Would I need a circuit like you posted in the schematic above or could I do it more simply?

I am not good at reading schematics for electronic circuits.
 

stardustsailor

Well-Known Member
Nice project you've got going.

I am interested in the pwm controller for your fans. I have a 4 wire 120mm fan exhausting my veg tent right now and I just have the blue wire hooked up to a toggle switch to ground with the black fan ground wire, so it is operating at low speed with the switch on. It is too loud at full speed but I know I could get a lot more cfm out of it if I could pwm the blue wire to ground.

Would I need a circuit like you posted in the schematic above or could I do it more simply?

I am not good at reading schematics for electronic circuits.
yes you'll need a circuit exactly like that ...
And that is one of the most simplest 'pwm signal ' circuits,with adjustable duty cycle ...
In fact ,it can't get more simple than that ...
In the diagram it looks complicated ,but it is not ..
You can use those pre-perforated pcbs ,and make it ...

I'll gladly help you out ,as much as I can ,if you wish ...
 

stardustsailor

Well-Known Member
Here 's a 'simpler' version of the pwm controller schematic....
PWM SIMPLE.jpg

RT pot ,adjusts pwm duty cycle ( range : ~1 % to >98% ) ,thus adjusts the power of fans
(1%- 99% ) ...

It's value sets PWM frequency along with the metalised film type ,timing capacitor (CT) ...

The formula to set the desired frequency is 1.44 / ( RT * CT )
RT in Ohms
CT in Farads

( 1K=1000 ohms
10K= 10000
and so on ...

1 nF = 0.000000001 F
10 nF =0.00000001 F
1uF= 0.000001 F
10 uF= 0.00001 F
and so on ... )
 
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stardustsailor

Well-Known Member
Some more info about this type of PWM generator


http://www.dprg.org/tutorials/2005-11a/index.html

(...)I've shown a silicon diode D3 across the output terminals – this is needed with inductive loads like small DC motors to protect the transistor against reverse EMF. A 1N4001 is OK for bipolar transistor switches, the faster UF4001 is safer if you use a MOSFET switch. With "brushless" computer fan motors it's not necessary to fit this diode as they have any needed protection already in-fan. It's also not needed with lighting control.(...)

http://www.pcsilencioso.com/cpemma/555pwm.html
http://www.pcbheaven.com/circuitpages/PWM_Fan_controller_using_a_555/
http://pcbheaven.com/wikipages/PWM_Modulation/

(...)R2, R3 and C3 form a kickstart circuit which keeps 555 in reset state for about 2 seconds. If you want to use this circuit with V+ other than +12V, then it is a good idea to increase R2 value so that (V+ * R2)/( R2 + R3) is about 2, because the reset signal treshold is about 0.5..1V. If you do not do that, then the kickstart signal will probably stay too close to reset treshold.(...)

http://www.nomad.ee/micros/pwm555.html

A 'kickstart' is used to 'cold start' a fan ,in a voltage lower than it's typical..
If a fan is slowed down,using pwm voltage control,if switched off ,it needs a kickstart circuit
to start operating again,if switched on ..
( for 1-2 " at full speed and then drops to pre-set speed ) ...

Kick start is done with two resistors (30K +150 K )and one cap (220uF,electrolytic 35V ) at pin 4 ( Reset ) of the 555 timer ....

Best frequency range for fans : 100-300 Hz
( 100 K pot and 100 or 68 or 47 nF timing cap )
 
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stardustsailor

Well-Known Member
The circuit with the kickstarter ..
(for general fan pwm control )
Freq :100K pot & C4 cap value: 100n =~100Hz/ 68n = ~200Hz / 47n = ~300Hz
Operate only at 12 V ,12A max .

! Do not short-circuit the output (PS1 & PS2 ),while the circuit is powered !
The Drain of the mosfet will fry .It is unprotected .

pwm with kickstart.JPG
 

stardustsailor

Well-Known Member
The first circuit (using the 74AC14 Hex Inverter ) has to be powered from 2 to 6 VDC ..
Thus needs it's own power supply /voltage regulator ..

The second utilises CMOS devices ...
VERY-VERY SENSITIVE to ESD ...

The super -slim fan is piece of art !
But I got a good price on those Sunons ...
40 Euros for 4 of them ,ain't that bad ..

Glad to see you ,dropping by this thread !
BTW ....What's going on ,at your lab ,brother Guod ?
Are you building something new ?
 

stardustsailor

Well-Known Member
I'm thinking placing a K type thermocouple in one of the CXA's ,with output posts
as a reference Tcase measurement,using a multimeter

I can also have an Arduino ,taking samples of the temperature
and if the temp rises over a certain threshold ,to cut-off the AC power to the drivers ,through a relay,
while leaving the fans operational ,until temps lower ....And then power up the drivers again ...

But all that extra circuitry needs space ....

And already four of those heatsinks together ,make a really big led light fixture/panel ....
 

stardustsailor

Well-Known Member
Can I ask what program you use for this? I hand draw and hate it becuse I cannot post my ideas. Beautiful designs!
I use the free-version of Google SketchUp,with some added (also free ) plug-ins ...
It is way easy to learn and use (althought it has plenty of tricks/secrets and ..weirdo glitches ) with a large open
3D model library and tech stuff (ANSI/DIN pipes,bars,angles,etc ) ..
And has a lot of potentials ..(even photo realistic rendering capabilities ,with render plug-ins like Pov-Ray )..

Since I've learned to use it a bit ,I never again designed/drawed by hand ...
Sketching Up ,only ...
gd-sds box 1.jpg

gd-sds box 2.jpg


new model all white 1.jpg

new model all white 2.jpg
 
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stardustsailor

Well-Known Member
The box that is going to house the led fixture is going to be something like these ones :
box.gif
box 2.jpg
box 3.jpg

In the front panel ,there are going to be installed all the control pots,switches ,voltmeters ,amperemeters etc ...

In the back the Ac inlet ..
On the top lid the four fans and the hanging rings ...



Some materials are starting to arrive ...
P4121006.JPG

Other parts ,are already under construction (Fan PWM controller )
P4121005.JPG
The fan psu (MeanWell open-frame PS-45-15 ),the parts for the pwm circuit-pcb is bathing right now- and guess where I like the blue color in leds ?
Yes ! In the 7-seg numerical displays ! A blue digital voltmeter ,to indicate the operational power level of fans
( P out = P ini * Duty Cycle % ) ,through volt indication


And a side- project/add-on under consideration ....
P4121003.JPG


An Arduino ,a K-type thermocouple ,couple of ACS712 hall sensor for measuring current up to 5A ,a shield with
relay interface ,thermocouple (type K ) interface ,2x 8 lcd blue light screen and its interface ,a buzzer ,user and reset buttons & indicator led......(once used for reflow oven controlling ,now not used anymore ... )
expand mask.JPG


hall sensors.JPG

Now ...Arduino ,with those add-ons can measure rea-l time Case Temperature of a single only ' diagnostic reference ' CXA chip , current and voltage ( with v.divider )
If things get out of ..limits ..( Tc =90°C ,Vf=42 Volts ,If=1950mA +8% => +156 mA,say ~200mA => 2150mA max limit ),
then an annoying buzzer will start buzzing for one-two times ,sec or mins and a relay will cut-off the power ..
to the drivers ,until parameters are back to normal/typical ....

Also it can display case temperature and current / voltage of the control/diagnostic reference CXA chip ...

Things would get really expensive and complicated to monitor all the CXA chips ,real-time ..
One will do ,I guess ,for reference ...

Hmmm a led chip diagnosis tool ....
As an external device ....
Like a multimeter for leds ....
Hmm...
 
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