On Jul 20, 2011, at 7:55 AM, Neil M Califano wrote:
The power consumption of the R4a is 60 watts and I'd like to run the
radio off my 12 volt car cigarette lighter using a 130 watt PSW
inverter. I think the fuse is 10 amps. So 12.5 volts x 10 amps=125
watts. But I heard of fuses blowing running only laptops. It looks
good on paper, but practically will this work?
Probably not.
1. The inverter is rated 130VA (you can look up the reason why, and
what a VA (volt amp) is, but suffice it to say that a 130VA inverter
will max out (and possibly go fizzle pop without a good fuse or
overload protection at 91 watts. That is of course assuming that it's
a 130VA inverter in the first place, based on the specs you gave it
it's 130VA INPUT.
2. The inverter is barely 50% efficient. If you are lucky, you can run
a 65 watt laptop off of it, but probably not. My GUESS is that it's 91
Watts input and 30-40 watts out.
3. The R4a uses 60 Watts (or so) with the volume set at a reasonable
level. That's how things were rated in those days. It may draw a
little more with a loud station, and often draws less BUT it's a tube
radio. Tubes draw lots of current when cold and as they warm up draw a
lot less. So if for a short time the tubes draw 100 watts, or 200
watts, or even 300 watts, no fuse will protect your inverter, it will
be toast.
4. Inverters are just switching power supplies. They put out lots of
noise and so on. The really cheap ones put out square waves instead of
smooth sine waves, and you won't be able to hear anything over the
noise.
Geoff.
--
Geoffrey S. Mendelson, N3OWJ/4X1GM
Making your enemy reliant on software you support is the best revenge.
___
Drakelist mailing list
Drakelist@zerobeat.net
http://mailman.zerobeat.net/mailman/listinfo/drakelist
