On Wed, 22 Jul 2009 10:05:27 -0700, FatBytestard
wrote:

On Sun, 19 Jul 2009 19:35:22 -0700, Jeff Liebermann
wrote:


My clamp-on amps guesser has a peak hold function. I'll try it out on
some of my LaserJet printers in the office and see what it shows.

Wont you have to open up the IEC power cord and clamp only a single
path?

Nope. I have an adapter that came with a Radio Shock clamp on
Amps-guesser. 22-161 multiplier.
http://support.radioshack.com/support_meters/doc21/21584.htm
It's the device on the right. It's a double loop, with 10 turns in
one loop, and one turn in the other. With the clamp-on ammeter in the
10x loop, the current readings are 10 times larger, making low current
readings much easier. In the 1x loop, it effectively splits the line.
Very handy.

Incidentally, the clamp-on meter is a Honeytek A902 that I bought on
eBay many years ago. Not great, but it has the features I wanted. 2A
full scale, temperature probe, and peak hold. The peak hold is handy
for measuring laser printer inrush current, but I was more interested
in the peak current at a remote radio site, where transmitters are
constantly and randomly drawing current.

I also notice that many of these are powered with standard 10A IEC line
cords. How can that be right for a device with such high usage
declarations?

Dunno, but I can guess. Current capacity standards for device cords
are tested for maximum wire heating. While the 23A inrush current
might seem rather high, it only appears for perhaps a second, when the
fuser initially warms up. After that, the operating current of the
laserjet is well withing the current limitations of a common #14AWG
power cord. Try it. Does the cord get warm when furiously printing?
Probably not.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558