Transformers and grounds

soundNERD · 16th February 2004, 01:05 PM

I am building a lm3886 subwoofer amp, and want the thing to look professional. So, I bought an aluminum plate from Science and Surplus (a local surplus store), and assembled the thing on it.

IS it safe to have the transformer mounted directly to the aluminum? I know that nothing happens when it is touched.

Here are the pictures of the unit. The amp is not done and I have to get around to drilling the hole for the switch. All thats on there is is the trafo and power supply board.

Is this safe?

hacknet · 16th February 2004, 01:40 PM

i guess its perfectly fine aslong as you earth the casing to be safe.

peterpan73 · 16th February 2004, 05:21 PM

Hello,

I am wondering whether its possible to use a welding transformer to power up a rack full of PA Amps (say 5 to 10KW RMS) as welding trannies are cheaper in my country, produces a large current-350 to 1000Amps at a low voltage -20 to60V.iIf its possible what kind of rectifiers and filters should I use.
I like this idea to keep down costs. The amps are for live sound reinforcement.
Please let me know at the earliest.

Desperate peterpan.

soundNERD · 16th February 2004, 09:14 PM

Yes, if it is center tapped.

but nowhere ar you going to find a 1000A rectifier, most likely not even 350A.

-Mike

peterpan73 · 17th February 2004, 02:27 AM

Hey thanx there Mike,

BTW... I have been thinking about the very high current rectifiers and am thinking of using industrial rectifiers either from www.abb.com or www.irf.com.

Would you be kind enough to select a good rectifier for me from these places. There are too many of them there and I am a bit confused of the right one add to that the fact that I'm technically competent too. and yes the filter too please!!.

Peterpan

peterpan73 · 17th February 2004, 02:30 AM

incompetent I mean!!!

Peterpan

runebivrin · 17th February 2004, 10:14 AM

Well, you're gonna need a pretty hefty bank of capacitors to stabilize that. It might be a simpler idea to use separate bridges and cap banks, connected to a single transformer.

Rune

soundNERD · 17th February 2004, 12:52 PM

Could you tell me the exact specs of the transfomer?

peterpan73 · 17th February 2004, 01:05 PM

Thanx there Mike,

Looks like we're online... why don't we chat about this... my YahooID in yahoo messgr is patrick_pugh2000

Patrick

peterpan73 · 17th February 2004, 01:11 PM

OK the tranny is 230VAC Pri, 20-0-20VAC Sec, 350Amps

16th February 2004, 05:21 PM	#3
peterpan73 diyAudio Member Join Date: Feb 2004 Location: Nevermind	Crazy transformer idea Hello, I am wondering whether its possible to use a welding transformer to power up a rack full of PA Amps (say 5 to 10KW RMS) as welding trannies are cheaper in my country, produces a large current-350 to 1000Amps at a low voltage -20 to60V.iIf its possible what kind of rectifiers and filters should I use. I like this idea to keep down costs. The amps are for live sound reinforcement. Please let me know at the earliest. Desperate peterpan. __________________ Thinking is the Hardest Work there is. Which is the probable reason why so few engage in it.

17th February 2004, 02:27 AM	#5
peterpan73 diyAudio Member Join Date: Feb 2004 Location: Nevermind	Welding transformer Hey thanx there Mike, BTW... I have been thinking about the very high current rectifiers and am thinking of using industrial rectifiers either from www.abb.com or www.irf.com. Would you be kind enough to select a good rectifier for me from these places. There are too many of them there and I am a bit confused of the right one add to that the fact that I'm technically competent too. and yes the filter too please!!. Peterpan __________________ Thinking is the Hardest Work there is. Which is the probable reason why so few engage in it.

17th February 2004, 02:30 AM	#6
peterpan73 diyAudio Member Join Date: Feb 2004 Location: Nevermind	correction incompetent I mean!!! Peterpan __________________ Thinking is the Hardest Work there is. Which is the probable reason why so few engage in it.

17th February 2004, 10:14 AM	#7
runebivrin diyAudio Member Join Date: Jul 2003 Location: Huddinge, Sweden	Well, you're gonna need a pretty hefty bank of capacitors to stabilize that. It might be a simpler idea to use separate bridges and cap banks, connected to a single transformer. Rune __________________ Do wizards use spell checkers?

17th February 2004, 01:05 PM	#9
peterpan73 diyAudio Member Join Date: Feb 2004 Location: Nevermind	Thanx there Mike, Looks like we're online... why don't we chat about this... my YahooID in yahoo messgr is patrick_pugh2000 Patrick __________________ Thinking is the Hardest Work there is. Which is the probable reason why so few engage in it.


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16th February 2004, 01:40 PM	#2
hacknet diyAudio Member Join Date: Nov 2002 Location: sg	i guess its perfectly fine aslong as you earth the casing to be safe.

16th February 2004, 09:14 PM	#4
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	Yes, if it is center tapped. but nowhere ar you going to find a 1000A rectifier, most likely not even 350A. -Mike

17th February 2004, 12:52 PM	#8
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	Could you tell me the exact specs of the transfomer?

17th February 2004, 01:11 PM	#10
peterpan73 diyAudio Member Join Date: Feb 2004 Location: Nevermind	Tranny info OK the tranny is 230VAC Pri, 20-0-20VAC Sec, 350Amps __________________ Thinking is the Hardest Work there is. Which is the probable reason why so few engage in it.

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