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Re: Can a power supply have too much current?



Alex Freed wrote:

> "Tristan Mumford" <xtristan.xmumford@xgmail.xcom> wrote in message
> news:45e61141$0$91139$c30e37c6@lon-reader.news.telstra.net...
>>
>> Anyway, IIRC the +5v is roughly 15A, the 12v is roughly 5A. Usually I'm
>> happy about having more current. However the difference here makes me
>> more than a little nervous.
> 
> There are two issues:
> 
> 1. Some power supplies require a minimum load. In most cases this is not
> an issue.
> IIGS will definitely load it enough.
> 
> 2. If there is a short on the board the damage will be greater with a
> power supply that
> does not cut out at say 2 amps but happily burns the traces at 15 amps.

Yeah. The short condition is what worries me. A lot.

> 
> And also there is always a chance you miswire the outputs.
*Sigh*. Yeah. That is so true. R.I.P. Streetfighter II Champion Edition
JAMMA arcade machine :(

> So if I were 
> you I'd first
> try to find an old-fashioned transformer to get 110V. In fact if you have
> ANY large
> enough power transformer it will likely have a split primary. Easy to get
> 110V.

I have one. However I'm somewhat reluctant to touch it. It's in my Radical
Radial arcade machine. It seems as though LAI's earliest machines were
imports. They just plopped a 240 - 110v stepdown transformer in to make
things easier. But... The last time I looked at that wiring I gave up. It
made no sense to me whatsoever. The machine works so I decided not to
question it.
New stepdowns cost about $75 so that's out. Pity. My partner has some things
that she can't use because of that.

Let's look at options. What kind of things may contain a transformer with a
split primary winding?

Thanks,

Tristan.

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