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Wiring A Flow Controller

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breakbeer

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Hi Guys,

Having a few problems getting this little flow controller to work with my little brown pump

I bought a PWM voltage controller from evilbay

PWM_voltage_regulator.jpeg

and put it into a small box I had lying around and added a switch

flow_controller.jpg

I tried to test it and just by-passed the switch & connected the + and - from the board to the connector that attaches to the DC adaptor. The little LED light turns on but nothing from the pump

any suggestions where I've gone wrong?
 

rusconi

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Hi Breakbeer

I have 3 similar controllers working.

One thing to look out for is those green connectors on the pc board.

If they're like mine they are a plug/socket arrangement which don't seat correctly if you're not careful.
Also the wires from the brown pumps are narrow and may need extra tightening on the terminal.

Do you have a multimeter to test the output?
could be a dud controller

Cheers Russ
 

andytork

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Failing the above, chuck a capacitor accross the motor the wires, could be a supply de-coupling issues which happens a lot with PWM of DC motors
 

breakbeer

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Thanks guys, I have access to a multimeter & capacitor at work
I'll also triple check the wire connections
 

dent

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Being as these are DC brushless motors, they will have their own controller electronics to run the motor in the pump, which may not operate when driven directly with PWM.

I would test your PWM controller with a lightbulb or brushed motor (out of a toy or dremel maybe) to see if it works - even a speaker (with a series resistor) will make the buzzing noise which would indicate the switching is working. If it does, that would indicate that the above is your problem.

Really though if you want to adjust your flow, a ball valve on the output of the pump is the usual solution.
 

Golani51

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Being as these are DC brushless motors, they will have their own controller electronics to run the motor in the pump, which may not operate when driven directly with PWM.

I would test your PWM controller with a lightbulb or brushed motor (out of a toy or dremel maybe) to see if it works - even a speaker (with a series resistor) will make the buzzing noise which would indicate the switching is working. If it does, that would indicate that the above is your problem.

Really though if you want to adjust your flow, a ball valve on the output of the pump is the usual solution.
Does it not put the system under excessive strain by preventing flow?
 

dent

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Does it not put the system under excessive strain by preventing flow?
Nope, it is business as usual. The only thing you don't restrict is the inlet.
 

leahy268

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Just thought I'd add this from an original email from the supplier about the said pumps..


Hello
Warwick,

For your questions, please reference the details as follows,


-- Yes, for our these pump, you can vary the speed
by reducing the voltage
.
Let me know if you can't though.. Haven't had a chance to try this out with mine as yet..



Warwick
 

Robbo2234

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maybe just a 200k potentiometer?
 

dent

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Yeah, you can slow them down by reducing the voltage. The PWM controller does not do this however. PWM is just turning the full voltage off and on, very quickly.

You can't use a 200k potentiometer because you won't get sufficient current flow to run the pump.

You can use a potentiometer along with a medium sized transistor, but this will generate a fair amount of heat.
 

Robbo2234

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what size potentiometer would you recommend?
 

dent

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You cannot in practise use a potentiometer directly, as you would require a large expensive one for this job.

See attached image for the simple transistor circuit that will work. The transistor will need to be on a heatsink as it will use all the power that the pump is not using.

circuit.gif
 

Ducatiboy stu

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Mmm... electronics 101..

All them fancy controllers and a simple transistor does the same job :rolleyes:
 

AlexL

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Failing that,

I use one of these to control a PC fan for a stirrer and another for a set of LED lights. Both work flawlessly and at $5 you can't really go wrong. They're rated at up to 8A (questionable) but should be ok for the 1A the little brown pump draws.

Alex
 

Wolfy

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Wont a ballvalve on the outlet serve the same purpose?
That's what I use, works fine.
However, since they are not 'true' magnetic-drive pumps, I presume that the life-span of the pump might suffer as a consequence, or that they will just stop working (again) one day soon.
 

QldKev

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Why not use a ebay led dimmer? They come in 12 and 24v versions.


For the 12v one, remote control for $6.50 here (note product has 12-24v on it)
 

leahy268

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Well there you go.

I had always thought that pwm would have worked for just that purpose.
Though reading I see why that might not work.

Had originally hoped to software control the pump..
Might have to go back to the drawing board on that one.

:p
 

breakbeer

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Yeah, I could've just put a ball valve on the outlet but I'm enjoying the little projects that come with home brewing.
Might just get one of those dimmers
 

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