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Help with temp. control fan hardware


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digital-guy

Tue Dec 02 2008, 08:21AM

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hi, I am a beginner when it comes to hardware so i though that i should get some help.
I want to make this temperature controlled fan and since i am using 15V AC power supply instead of 230V AC. what i want to know is if i would have to change the triac and the resister shown in the diagram below and also if i can use MOC3041 Triac driver optoisolator (RC) instead of MOC3011 ??
any help will be much appreciated.

Arun Kumar V

Tue Dec 02 2008, 10:59AM

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the chances are that the opto isolator/driver may not work at such low voltages. the triac will work. you can get rid of the MOC3021/11/41, if you can rectify the 15 VAC into DC and directly use the triac (or SCR) with 1K resistor to its gate and use a normal optocoupler like PC817 or MCT2E

Arun

[ Edited Tue Dec 02 2008, 11:02AM ]

ExperimenterUK

Tue Dec 02 2008, 02:02PM

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Hi |digital-guy

As a beginner I would recommend you use a relay instead of the BT136
and the MOC3011
Put the output of pin 22 through a 1K resister to drive a transistor,
to operate a relay.
What wattage is your fan ?

Learning all the time

digital-guy

Tue Dec 02 2008, 02:53PM

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thankyou for your reply arun. but from this all i understand soo far is to keep everything in the circuit and replace the MOC3011 with optocoupler as shown in the diag below. what i dont understand is to where to put the rectifier on the circuit. I mean if i convert the ac to dc, what value of dc would this give me? and if i am converting ac into dc then can i use both ac and dc fans ???
can i use optocoupler ISP815 instead of pc817 or mct2e because i cant find them. and can i also use "DF01 BRIDGE RECTIFIER 1A DIL4 RC" on my circuit?
sorry to ask u soo many questions but i'm soo confuesd

updated diagram: http://www.geocities.com/niu_logic/circuit_diagram2.GIF

PS: the fan is 15V AC and the rest of the information is on the circuit diagram in the link above.

[ Edited Tue Dec 02 2008, 03:09PM ]

Arun Kumar V

Wed Dec 03 2008, 07:32AM

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Hello digital-guy ( nice name like Cable -Guy)

i have drawn the circuit to make things clear, pl.go thru it :

Arun

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digital-guy

digital-guy

Wed Dec 03 2008, 04:44PM

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hello arun... good thing that u like my name

i was just wondering if the rectifier converts the 15Vac into 15Vdc can i just use a 15V or something dc power supply and remove the rectifier from the circuit?
and also on ur diagram above u have 5pins for the optocoupler. pin5 for +5V dc, pin4 going into resistor and what about the rest, is pin1 going into the port 22 of the microcontroller and where are the rest of the pins going?

Arun Kumar V

Wed Dec 03 2008, 11:36PM

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Hello digital-guy,

First things first - tell me which supply are you actually using for the Fan motor ? AC or DC

Yes, if you use DC supply for fan then you can remove the bridge ( but you first said you had 15V AC ). The LED part of the optocoupler in my diagram should be connected the same way its in your original schematic. and you don't have to connect the pin 6 ( collector), leave it floating.

I think you have to be clear in what you intend to do, you had first said you have a 15V AC supply for fan and now you are saying you have 15VDC supply - if the latter is true then you can simply use a power mosfet to run the DC fan ( BTW you haven't said anything about fan's wattage).

Arun

digital-guy

Thu Dec 04 2008, 10:43AM

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.

[ Edited Thu Dec 04 2008, 10:45AM ]

digital-guy

Thu Dec 04 2008, 10:48AM

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hello arun
im very sorry if i have not made it clear about my power supply. basically i am still thinking about the power supply and which one to use. looking at my options now...i think i should use a 15V dc power supply as i wont have to use the bridge. this also means i should use a 15V dc fan. So u mean the circuit should look like this below if i am using 15v dc power supply and 15v dc fan.