fusible link questions

Clarence L.Snyder clare.snyder.on.ca at ibm.net
Mon Feb 8 02:34:08 GMT 1999


Steve Sassine wrote:
> 
> On Sun, 7 Feb 1999, Justin Guest wrote:
> 
> > This could be quite useful if you controlled it properly. A lot of people
> > spend a lot of money trying to increase 12v up to something useful for
> > ICE. Does anyone know how to get an alternator to deliver higher
> > voltages. I was looking at this sort of design with two alternators in
> > mind one running at 12v and the other at a higher voltage. Its a long
> > time since I did my HNC and I was not really interested in generators and
> > alternators at the time.
> >
> > Sorry this is not about EFI but it is electronics.
> >
> >
> > Regards Justin Guest
> > Email as header or jg55776 at glaxowellcome.co.uk
> > Phone +44 (0) 1229 482549
> >
> >
> > >On Thu, 4 Feb 1999, Steve Sassine wrote:
> > SNIP
> > >
> > >Canadain tire used to sell a box that would output 120 vdc from the
> > >alternator. it just full fielded the alt and at around 1500 rpm 120 v
> > >
> > >scarry eh
> > >
> > SNIP
> >
> 
>       It is not vary hard to also get 120 v ac at 50-60 hz. Remember that
> most alternators are three phase sync motors. The Three phase output
> voltage is rectified using a full wave bridge rectifier. This low voltage
> output, say is is at 12v RMS, can be stepped up using a step up
> transformer. You only need to by-pass the bridge rectifier. Also need to
> check the sine wave for different higher order harmonics. This set up can
> also regulate the ouput voltage.
> 
>  from steve sassine
If you get 60CPS at 1000 alternator RPM, I'm sorry to have to tell you
you won't get much output from it. The faster you spin it, the more
output you get. Usually "geared" about 3:1 to the engine, at 2000 RPM
coasting down the highway you are spinning the alt at about 6000 rpm,
and producing 3 phase AC at360 cps. The 400CPS previously mentioned is
AWFULL close to what you will see at highway speeds. If you want AC from
an automotive alternator, just get a decent inverter.Spikes of current
draw are buffered by your battery so you don't fry the alt, frequency is
steady, as is voltage. You will likely pick up the inverter for less
than it costs to convert the alternator to a useless piece of junk,
assuming you value your time at anything over about 50 cents an hour.

I snagged a 1500 va unit from an old Bell Telephone truck for $75
canadian dollars. That's about 50 US Greenbacks.



More information about the Diy_efi mailing list