Amprobe model RS-3 problem

[captainvi...@yahoo.com]

I picked up this probe at a yard sale for 5.00. After cleaning up the
connectors and installing a new AAA battery it works on resistance and
voltage ranges with the accessory cables supplied but when clamped
around a current carrying conductor it reads zero. I'm guessing that
there must be some kind of coil wrapped around the jaws internally on
this thing in some way. Current flowing through a conductor would
induce a voltage into this "primary" with a "secondary" connected to
the meter. I'm guessing here. I'm not really sure what is inside of
this meter. Can anyone tell me something about the theory of this type
of instrument and if they have any experience with this model. I may
have to get inside and would really appreciate some help with that as
well. There doesn't seem to be an easy way to do that without a
special tool. The company was no help at all.Thanks, Lenny.

[Dave M]

<captainvi...@yahoo.com> wrote in message
news:6b377398-b223-4636...@q2g2000vbr.googlegroups.com...

I'll bet that you clamped the current jaws around a 2 or 3 conductor cord,
right? If so, your meter will read zero all day, no mater how much current
you have in the wires. Oh, and it must be AC current; it won't work on DC.
The reason that the meter won't work if clamped around both conductors in
the cord is that the fields created by the current cancel each other.
You'll have to split the cord so that the clamp only has one of the
conductors inside. Then, it should work as advertised (assuming that
nothing is defective in the meter).
I recommend the line splitter at
http://www.licensedelectrician.com/Store/AM/ELS2A.htm. It will allow you to
check current on an appliance without having to split the cord open to
isolate the conductors.

You can download a copy of the manual for your meter from
http://www.amprobe.com/manuals/RS3.pdf

Cheers!!! Great find!!!
--
Dave M
masondg44 at comcast dot net

One good thing about Alzheimer's; you get to meet new people every day.

[Shaun]

"Dave M" <mason...@comcast.net> wrote in message
news:86adnVefu8ciuqHX...@giganews.com...

If that doesn't do it, open up the meter and look for two small diodes
connected to the pickup coil on the clamp and check them with a multimeter,
they often fail when someone puts too much current through it.

Shaun

[captainvi...@yahoo.com]

On Jun 19, 8:38 pm, "Shaun" <sc...@nomail.com> wrote:
> "Dave M" <masondg4...@comcast.net> wrote in message
>
> news:86adnVefu8ciuqHX...@giganews.com...
>
>
>
> > <captainvideo462...@yahoo.com> wrote in message

> Shaun- Hide quoted text -
>
> - Show quoted text -

I went back and read my post because I thought that I was very
explicit when I said that I "clamped it around a current carrying
conductor", meaning one side of the line. I suppose that I should have
said that. The diodes sound like a great idea to look into however to
open this thing it looks like there are two hex nuts surrounded by a
thick sort of plastic shoulder which makes it impossible to get a
socket on to. Any ideas? Thanks, Lenny.

[Wild_Bill]

Your description is correct, as far as the older models that I've seen.
Newer models that also read DC current use a hall effect device for sensing
the DC current, from what I've read about them.

If the jaws are laminated steel, they're probably just about indestructable,
but if they're formed ferrite material, there may be a break in a "jaw"
section, interrupting the induction path.
The break might not be a physical fracture from abuse, instead, it could be
some foreign material interrupting the magnetic circuit. The parts of a
ferrite inductive pickup should meet squarely, with no gaps.

The hex nut locations you described in your follow-up post sound like the
associated screw heads may be in recesses on the opposite side, and that the
screw heads may have been concealed by some sort of filler that
conceals/obscures their location, and also lets the manufacturer know that
the case has been opened (voiding any warranty obligations).

In old equipment I've seen asphalt-type filler used to conceal fasteners,
and newer equipment a silicone or a hot glue-type filler has been used.

--
Cheers,
WB
.............

<captainvi...@yahoo.com> wrote in message
news:6b377398-b223-4636...@q2g2000vbr.googlegroups.com...

[Shaun]

<captainvi...@yahoo.com> wrote in message
news:a10484e6-1596-44ea...@u10g2000vbd.googlegroups.com...

I used to use a small pair of needle nose plyers to open them, it's been a
while, over 10 years.
see if that works.

Shaun

[captainvi...@yahoo.com]

I got it open.Now I'll have to take it apart and see Thanks Lenny.