On Sat, 05 Sep 2009 10:25:47 -0400, "Michael A. Terrell"
wrote:

A clamp on ammeter is fine for some uses. It doesn't log power
consumption. It is a tool intended for electricians, and most do not
give accurate readings on anything other than a pure resistive load.
Reading the actual load of a switch mode power supply requires a good
RMS converter in the meter. The same as the ones mate for the new
electronic watt hour meters. Its a poor worker who doesn't understand
his tools, yet defends bad work.

I use both clamp-on and inline meters. The clamp-on is best for
troubleshooting while the inline is best for monitoring. My no-name
Chinese clamp-on meter does accumulate usage (logging), but does not
have the power factor correction I need for dealing with inductive
loads (motors), or badly designed switchers. The inline can also do
cost calculations, which is something my customers can see and
understand.

However, the big advantage is that I can buy the inline meter for
about $27, do my song and dance for the customer, and then sell it to
him for about twice that. It also give the customer the impression
that I'm tryting to save him money by monitoring his electricity
usage. It's design makes it acceptable for leaving it in place for
monitoring, while a clamp-on meter plus inline cord splitter, would be
an ugly mess.

Note: I'm not an electrician. This week, I fix computahs. Computer
owners often want to know how much power their PC or monitor is
burning. Hmmm... I just bought myself a new desktop and forgot to
measure it.

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