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 Post subject: A good transistor for high power output fans
PostPosted: Thu Jan 10, 2013 11:32 am 
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Hi all,

Thankyou again to Imhotep, Shiva, Mr Brown, Stargate22, Sucahyo.
I have had a good time making these fans although it has been frustrating due too my lack of knowledge.
I progressed from building fans that were already wound to winding my own and thats when I blew my first npn3055.
Oh those were the days.
Then I went on to bifiller and tri filler and quad filler.
Then with stargate22's inpiration I built a hex filler.
Thats when the trouble started I continually blew transisters and the search for a golden transistor that could handle the excess voltage spikes began.
I have a six inch fan and a 10 inch fan I still have to build and I wanted to solve the problem of the transistors blowing I asked as many people as I could and all the response seemed to be was make sure you have a battery connected or capacitor.
I could not accept this and kept buying trialing and blowing every transistor I got my hands on.
I even tried the ones rick and john bedini reccomends for his 10 "fans and I blew them.
I have some light I have found a transistor that can handle the voltage spikes and is cheap.
It is mentioned below I found them on ebay it was my last resort I hope it gives people the security of not wasting money and a lot of time.
It only has a 20 amp max
although it has a 1000v max(I feel that this was the winner as its the spikes that go over the 100v, I have three transistors on the hex filler).

So go ahead and build that power fan.


http://www.datasheetarchive.com/BUT11A-datasheet.html
NPN Silicon Power Transistors H29BUTT11A TO-220 10pcs
Ebay
US $6.99
AU $6.65
postage
+ US $0.99
AU $0.94

Best Regards,

G.G.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Fri Jan 11, 2013 2:08 am 
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Thanks for sharing.

I see collector-base voltage = 1000VA with collector current = 5A.

What is 20A max ?


I think this 1000V rating transistor still wouldn't survive a direct spark from high power radiant output short.


I use 2SC2922, where collector-base voltage = 180VA with collector current = 17A. My son once forgot to turn off the charger without load for half a day. No load is the biggest stress for my stingo circuit, I think it should run at 1.5 Amp input. This transistor survive, the PNP die first. Other NPN transistor would already die.


BTW, TIP3055 survive much better than 2N3055.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Fri Jan 11, 2013 3:47 am 
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Yes my bad it only has a base current pulse of 4 amps, collecter current pulse of 10 amps. Though thats all it needs as I have not seen a fan produce sfw amps its all spiked volts.
As for weather it can survive I have seen it run and tried to kill it with my hex filler and it has not died and they do not get hot like every other types of transisters I have killed.
I have found test a theory, I am new to this and that is why I will test the boundaries.
Correct me if I am wrong although I believe the fans produce pulsated high volts not high amps.
The tip35c has a collector current continuos 25 amp, peak current 40 amp and base current 5 amp.
Although your 2SC2922 has the collector current 17amp and a base of 5 amps a total power dissaption (200w) double that of the butt11a(100w) and the tip35c has (125w).
The tip35c has higher amp ratings and lower voltage ratings so to me that proves why it is blowing up although as I mentioned the power dissaption may have something to do also.
Either way I have found a transistor I cannot so far kill anI have spent too much finding that out.
Now I will make a higher output fan when the wire arrives.
Regards,

G.G.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Mon Jan 14, 2013 1:52 am 
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I think we should calculate with ohm's law too.

If the coil has 1 ohm resistance, and the source is 12V (internal resistance assumed to be zero), then during transistor full ON, the current that pass the coil is 12 Amp. So, we need transistor for a pulsed 12Amp.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Tue Jan 15, 2013 2:00 am 
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wouldn't the motor mechanism use most of the amps?
Mr Brown always told me to forget about amps when dealing with these circuits due to the voltage spike.
My fan also oscilates without spinning. So the amps wouldn't be getting burnt when just oscillating right?
I could measure the amps used before charging and charging although I have had high amperage transistors and they all blew.
I believe I have found a transistor that is good for high powered fans I welcome improvements also it worked for me, cheap and reliable very rarely those words go thogether.
Regards,

G.G.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Wed Jan 16, 2013 12:02 am 
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When ever you have an electrical circuit with a voltage applied, amps will flow but with these circuits you have to watch the voltage as it will kill the transistors. As the voltage only occurs in short transients the amps do not have chance to ramp up but of course the higher the applied voltage the higher the amps.

It is when you have no load you have an infinite resistance so when the transistor switches off the coils will try to provide an infinite voltage exceeding the transistors' voltage rating.

Always make sure you have a charging battery connected, this way the voltage should stay in the safe zone.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Wed Jan 16, 2013 1:21 am 
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gmang73 wrote:
wouldn't the motor mechanism use most of the amps?
Mr Brown always told me to forget about amps when dealing with these circuits due to the voltage spike.
You have to watch for voltage spike during transistor shut OFF and pulsed amp rating during transistor ON.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Wed Jan 16, 2013 1:57 am 
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Fan when Standing oscillating, 881ma Opposite f what I thought when it spins it uses less amps.(learning)
Fan when spinning producing most nack emf 550 ma.
Transistors stay cold.

Regards,

G.G.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Sat May 10, 2014 12:34 am 
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I have given the masses time to find a better suited transistor that will allow the radiant energy to pass without blowing the transistor.
I compromised for the butt 11a although the tip 35c was a much better transistor for giving the purple flash.
Anyone experienced or not please pursue this.

Regards,

gmang73.


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 Post subject: Re: A good transistor for high power output fans
PostPosted: Sat May 10, 2014 4:25 am 
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I only used 1N3055 transistors and found them very good


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