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?
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?
Attachments
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.
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.
Yes, if it is center tapped.
but nowhere ar you going to find a 1000A rectifier, most likely not even 350A.
-Mike
but nowhere ar you going to find a 1000A rectifier, most likely not even 350A.
-Mike
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
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
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
Rune
Thanx there Mike,
Looks like we're online... why don't we chat about this... my YahooID in yahoo messgr is patrick_pugh2000
Patrick
Looks like we're online... why don't we chat about this... my YahooID in yahoo messgr is patrick_pugh2000
Patrick
Voltages of 20-0-20 seem rather low... Well since Welding Trafo's are cheap in his area, why not get two, connect them in series and get voltages of 40-20-0-20-40 ?
He can either use the 40-0-40 rails (or in a class-G configuration using all 40-20-0-20-40 rails.)
He can either use the 40-0-40 rails (or in a class-G configuration using all 40-20-0-20-40 rails.)
Tranny dillemma
Thanx a ton Rune and Mike,
Rune what is the Ampere rating for those Diodes?? MIke I still haven't figured it out how I can go about getting 40-20-0-20-40.
Would you mind sketching it out for me?? And by the way the welding trannies here are in the 40 to 60 V range however for a lil more spending I will have to arrange them to be lowered down to 20V as most of my homebrew amps work at that voltage for full power. I am seriously considering having more taps on the tranny to permit some flexibility.
Patrick
Thanx a ton Rune and Mike,
Rune what is the Ampere rating for those Diodes?? MIke I still haven't figured it out how I can go about getting 40-20-0-20-40.
Would you mind sketching it out for me?? And by the way the welding trannies here are in the 40 to 60 V range however for a lil more spending I will have to arrange them to be lowered down to 20V as most of my homebrew amps work at that voltage for full power. I am seriously considering having more taps on the tranny to permit some flexibility.
Patrick
Patrick,
I do not have sketching software. If the 20-0-20 works for you then forget what I said. 😉
But for discussion:
For a 40-20-0-20-40 scenario, you'd need two transformers and connect them in series. Let’s assume the 20-0-20 rails are represented as A-B-C for one transformer and A1-B1-C1 for the second transformer, and then you’d connect C and A1 together to create a virtual ground. (In this case the B and B1 will no longer be your center tap, they will become your 20 volt taps)
Therefore you’d have A-B-C-A1-B1-C1 where C and A1 are connected making your ground (0 volt), the B and B1 are your 20 volt taps and the A and C1 are your 40 volt taps.
What you don't want to do is connect them in paralell i.e. join Ato A1, B to B1 and C to C1 as you'd only get 20-0-20 @700 amps (unless thats what you want to do.)
Hope I didn’t confuse you more!
-K
I do not have sketching software. If the 20-0-20 works for you then forget what I said. 😉
But for discussion:
For a 40-20-0-20-40 scenario, you'd need two transformers and connect them in series. Let’s assume the 20-0-20 rails are represented as A-B-C for one transformer and A1-B1-C1 for the second transformer, and then you’d connect C and A1 together to create a virtual ground. (In this case the B and B1 will no longer be your center tap, they will become your 20 volt taps)
Therefore you’d have A-B-C-A1-B1-C1 where C and A1 are connected making your ground (0 volt), the B and B1 are your 20 volt taps and the A and C1 are your 40 volt taps.
What you don't want to do is connect them in paralell i.e. join Ato A1, B to B1 and C to C1 as you'd only get 20-0-20 @700 amps (unless thats what you want to do.)
Hope I didn’t confuse you more!
-K
AOK its crystal clear
K, yes thanx there, that is a good idea..... I get it now.
OK I'll look into that too. Right now I'm still haggling the price for one. By the way I'm a little concerned about the noise too and what kind of filtering would you suggest I make - choke or caps or both and what value??
Patrick
K, yes thanx there, that is a good idea..... I get it now.
OK I'll look into that too. Right now I'm still haggling the price for one. By the way I'm a little concerned about the noise too and what kind of filtering would you suggest I make - choke or caps or both and what value??
Patrick
soundNERD said:
Why not?
Try powerex, brown-boveri.
I've used the 25 mm die, the 67 mm die, 76, and looked at the 100 mm ones.. And powerex has some smaller modules of the size you are looking for..
The hockey pucks are good for multi-kiloamp applications..
The biggest problem is mounting them with uniform pressure..they require about 1500 lbs per square inch.
Cheers, John
Sorry, i have aim, not yahoo.
also, i looked at your two sites, didn't find anything.
and i guess i take my "you'll never find a 1000A rectifier" i should have said "i've never seen a 1000A rectifier"
20-0-20 is fine for amps. thats about +-25V after rectification and the caps right? thats PLENTY to run an amp...
-Mike
also, i looked at your two sites, didn't find anything.
and i guess i take my "you'll never find a 1000A rectifier" i should have said "i've never seen a 1000A rectifier"
20-0-20 is fine for amps. thats about +-25V after rectification and the caps right? thats PLENTY to run an amp...
-Mike
Looks like a grounding problem
Hello all,
Recently my electricity bills were soaring. I realised that we;ve consumed more than we normally do - monthly. I remember having this electrician chap do some wiring in the house. I feel bad to be telling you this... but prior to his coming to do my house wiring the wiring was not earthed. I mean earthing pit and all. I was putting it off hoping that I might be able to finish it off someday. Someday never came - I was too busy. I'd like to thank God that nothing tragic had happenned during that time. Anyway, this electrician earthed the wiring on my request. This was in December 2003.
However, I have reason to believe that there was AC leaking somewhere although I may be wrong about this. A few other things happenned. I was having a bath and when I touched the plumbing taps, etc, with my wet hands I thought I felt a mild tingy (often painful) sensation passing through. At first I thought I was a bit hypersensitive but later I realised that my wife and son felt the same. Then came the electricity bill with a huge figure (double the usual) - post December in Jan 2004. I clipped the earthing in the house yesterday and the tingly sensation in the bathroom plumbing ceased immediately. I need to get round an inspector to do a thorough checking of the wiring. I am now tryng to piece things together - Soaring Electricity Bill and plumbing that seems leaky with AC. By the way my plumbing and my AC lines never touch electrically at least - I have checked that out thoroughly myself.
Will someone explain this phenomenon to me please.
Patrick
Hello all,
Recently my electricity bills were soaring. I realised that we;ve consumed more than we normally do - monthly. I remember having this electrician chap do some wiring in the house. I feel bad to be telling you this... but prior to his coming to do my house wiring the wiring was not earthed. I mean earthing pit and all. I was putting it off hoping that I might be able to finish it off someday. Someday never came - I was too busy. I'd like to thank God that nothing tragic had happenned during that time. Anyway, this electrician earthed the wiring on my request. This was in December 2003.
However, I have reason to believe that there was AC leaking somewhere although I may be wrong about this. A few other things happenned. I was having a bath and when I touched the plumbing taps, etc, with my wet hands I thought I felt a mild tingy (often painful) sensation passing through. At first I thought I was a bit hypersensitive but later I realised that my wife and son felt the same. Then came the electricity bill with a huge figure (double the usual) - post December in Jan 2004. I clipped the earthing in the house yesterday and the tingly sensation in the bathroom plumbing ceased immediately. I need to get round an inspector to do a thorough checking of the wiring. I am now tryng to piece things together - Soaring Electricity Bill and plumbing that seems leaky with AC. By the way my plumbing and my AC lines never touch electrically at least - I have checked that out thoroughly myself.
Will someone explain this phenomenon to me please.
Patrick
dangerously funny
I bought a house back in 1983 in Antwerp
it was trhough an auction issued by the debt collector = a bank.
I knew there was quite some work to make it liveable but at least, the good news was that there was power, gas and water.....
little did I know........ It was in November that I entered inside and noticed that the cellar was remarkeable warm ........ my neighbor told me he had noticed some strange very slight vibration in his hallway so i went on a serch mission....
after doing a check on the electricity meter, I noticed that even with only one bulb active (the refrigerator etc still had to be deliverd, the whole house was empty, the scale on the Landis & Ghir meter was making a nice rpm!
after serious research I found out that the rebar construction inside the floor of the hallway, and consequently the ceiling in the cellar, was functionning as a gigantiic heating element...........
that was quite a surprise I had to install new wiring to that section because the old wiring had been encased!!!! in the concrete.
Also, I had 380 volts coming in the house, it had been a dairy store long time ago and they, the co., never bothered to remove the whole system.
J-P
I bought a house back in 1983 in Antwerp
it was trhough an auction issued by the debt collector = a bank.
I knew there was quite some work to make it liveable but at least, the good news was that there was power, gas and water.....
little did I know........ It was in November that I entered inside and noticed that the cellar was remarkeable warm ........ my neighbor told me he had noticed some strange very slight vibration in his hallway so i went on a serch mission....
after doing a check on the electricity meter, I noticed that even with only one bulb active (the refrigerator etc still had to be deliverd, the whole house was empty, the scale on the Landis & Ghir meter was making a nice rpm!
after serious research I found out that the rebar construction inside the floor of the hallway, and consequently the ceiling in the cellar, was functionning as a gigantiic heating element...........
that was quite a surprise I had to install new wiring to that section because the old wiring had been encased!!!! in the concrete.
Also, I had 380 volts coming in the house, it had been a dairy store long time ago and they, the co., never bothered to remove the whole system.
J-P
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