Do Wiggle Stick Meters Wear Out?

[Watson A.Name - "Watt Sun]

I bought a HP 721 PS on Ebay for thirty something incl S&H, does a
whopping quarter amp at 30VDC, and uses all germanium devices, even
the rectifiers, which are 1N91s I believe (they're not the original
GEs, but they're marked SD 91, and are in the old top hat package). I
put a PSO (phase shift oscillator) on it, which has its output driving
a red LED. The freq is .38 Hz, or about a cycle every 2.5 seconds.
So I get this 'fading red eyes' effect. Well, the little old wiggle
stick meter on the PS goes from about a half mA on up to 9+ mA, back-
and-forth, etc., along with the LED current.

This old timer PS is probably from the mid '60s, 'cause I remember
using one just like it back then. In fact, I've seen pictures of test
setups from the late '50s with them in the picture. So it's got a
lotta miles on it, but still going strong. The other day, there was
one on Ebay, seller wanted $19.99 min bid, and nobody bid on it, the
time just expired. I was watching the meter stick wiggle, and the
thought occurred to me, maybe this meter has been in use for 30+
years, but usually it's powered up and stays pretty much in one place.
But I'm keeping it moving back and forth continuously. I'm wondering
if these d'Arsonval meter movements ever wear out, or get gummed up.
I think they're not lubricated so that shouldn't happen. But with
jewels, what's the lifetime of the movement? A hundred thousand
operations? A million? I'm curious, just wondering.


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[Sam Goldwasser]

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

We are all on the edge of our seats awaiting your report.
I expect it will be a few years or decades though.

Higher quality meters may taut band suspensions which shouldn't wear
out, at least not in the same way.

I suppose that if this will keep you from sleeping at night, you could
install a switch to disable the meter. ;-)

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[Robert Baer]

"Watson A.Name - Watt Sun, Dark Remover" wrote:

I bought a HP 721 PS on Ebay for thirty something incl S&H, does a
whopping quarter amp at 30VDC, and uses all germanium devices, even
the rectifiers, which are 1N91s I believe (they're not the original
GEs, but they're marked SD 91, and are in the old top hat package). I
put a PSO (phase shift oscillator) on it, which has its output driving
a red LED. The freq is .38 Hz, or about a cycle every 2.5 seconds.
So I get this 'fading red eyes' effect. Well, the little old wiggle
stick meter on the PS goes from about a half mA on up to 9+ mA, back-
and-forth, etc., along with the LED current.

This old timer PS is probably from the mid '60s, 'cause I remember
using one just like it back then. In fact, I've seen pictures of test
setups from the late '50s with them in the picture. So it's got a
lotta miles on it, but still going strong. The other day, there was
one on Ebay, seller wanted $19.99 min bid, and nobody bid on it, the
time just expired. I was watching the meter stick wiggle, and the
thought occurred to me, maybe this meter has been in use for 30+
years, but usually it's powered up and stays pretty much in one place.
But I'm keeping it moving back and forth continuously. I'm wondering
if these d'Arsonval meter movements ever wear out, or get gummed up.
I think they're not lubricated so that shouldn't happen. But with
jewels, what's the lifetime of the movement? A hundred thousand
operations? A million? I'm curious, just wondering.

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Don't be ripped off by the big book dealers. Go to the URL
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http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
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@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

There are a lot of Weston meters still being used; mine was made in
1947 and still going strong.

 

[Isaac Wingfield]

In article <6w4qvkjonv.fsf@saul.cis.upenn.edu>,
Sam Goldwasser <sam@saul.cis.upenn.edu> wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

How about the strength of the magnets? Old magnets may not maintain the
same flux they started out with. Does that matter?

Isaac

 

[Watson A.Name - "Watt Sun]

In article <6w4qvkjonv.fsf@saul.cis.upenn.edu>, sam@saul.cis.upenn.edu
mentioned...

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

We are all on the edge of our seats awaiting your report.
I expect it will be a few years or decades though.

Sam, you're a card. Heh. I hope I'll be around for a few more.

Higher quality meters may taut band suspensions which shouldn't wear
out, at least not in the same way.

I hada high school friend who had a Simpson taut band meter. It
wasn't a 260, but a bigger meter where the meter movement itself was
most of the case. I think the movement was 20 uA, it was really low
current. Slow to move, but it had a mirror behind the needle.

I suppose that if this will keep you from sleeping at night, you could
install a switch to disable the meter. ;-)

Yeah, the range can be changed to higher curent or voltage where the
stick doesn't wiggle at all as long as I keep my fingers off the V
control. Funny, but these old PSes were built like tanks: they have
an aluminum chassis inside an aluminum case. Then later HP made the
6214A and 6216A PSes and the cases are so fragile and brittle that
they crumble when you try to take them apart. :-(

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Just when you thought you had all this figured out, the gov't
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[Sam Goldwasser]

Isaac Wingfield <isw@witzend.com> writes:

In article <6w4qvkjonv.fsf@saul.cis.upenn.edu>,
Sam Goldwasser <sam@saul.cis.upenn.edu> wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

How about the strength of the magnets? Old magnets may not maintain the
same flux they started out with. Does that matter?

Yes, it does matter. They are probably ALNICO magnest but used with
a very low exciting field (the current through the coil) so they probably
don't loose much of their strenght over time.

Good thought though.

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[Asimov]

"Isaac Wingfield" bravely wrote to "All" (29 Dec 03 05:30:49)
--- on the heady topic of "Re: Do Wiggle Stick Meters Wear Out?"

IW> From: Isaac Wingfield <isw@witzend.com>

IW> In article <6w4qvkjonv.fsf@saul.cis.upenn.edu>,
IW> Sam Goldwasser <sam@saul.cis.upenn.edu> wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

IW> How about the strength of the magnets? Old magnets may not maintain
IW> the same flux they started out with. Does that matter?

IW> Isaac

That's not very likely. The old magnets would have had to be subjected
to very high impacts or heat for them to weaken significantly. I've
never heard of magnetic domains snapping out of alignment on their own
but I haven't seen everything yet...

.... No electrons were harmed in the posting of this message.

 

[Jim Adney]

On Sun, 28 Dec 2003 16:44:48 -0800 Watson A.Name - "Watt Sun, Dark
Remover" <alondra101@hotmail.com> wrote:

I was watching the meter stick wiggle, and the
thought occurred to me, maybe this meter has been in use for 30+
years, but usually it's powered up and stays pretty much in one place.
But I'm keeping it moving back and forth continuously. I'm wondering
if these d'Arsonval meter movements ever wear out, or get gummed up.
I think they're not lubricated so that shouldn't happen. But with
jewels, what's the lifetime of the movement?

If it's actually a jewelled movement then there is likely some finite,
but large, lifetime. If it's a taut-band movement then I'd expect the
lifetime to be virtually infinite.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Chuck Harris]

Consider that pocket watches use a very similar jeweled bearing on
their balance wheel. The balance wheel rotates a few hundred degrees
5 times per second. Pocket watches are typically serviced every other
year. They last for hundreds of years.... and yes, unlike a meter,
they are oiled.

Your meter rotates a maximum of 60 degrees, typically. It would have
to go zero to full scale 5 times per second to get even close to a
pocket watch's bearing activity.

-Chuck Harris

Jim Adney wrote:

On Sun, 28 Dec 2003 16:44:48 -0800 Watson A.Name - "Watt Sun, Dark
Remover" <alondra101@hotmail.com> wrote:


I was watching the meter stick wiggle, and the
thought occurred to me, maybe this meter has been in use for 30+
years, but usually it's powered up and stays pretty much in one place.
But I'm keeping it moving back and forth continuously. I'm wondering
if these d'Arsonval meter movements ever wear out, or get gummed up.
I think they're not lubricated so that shouldn't happen. But with
jewels, what's the lifetime of the movement?


If it's actually a jewelled movement then there is likely some finite,
but large, lifetime. If it's a taut-band movement then I'd expect the
lifetime to be virtually infinite.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[DarkMatter]

On Mon, 29 Dec 2003 05:30:49 GMT, Isaac Wingfield <isw@witzend.com>
Gave us:

In article <6w4qvkjonv.fsf@saul.cis.upenn.edu>,
Sam Goldwasser <sam@saul.cis.upenn.edu> wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

How about the strength of the magnets? Old magnets may not maintain the
same flux they started out with. Does that matter?


Unless they were heated or affected by a demagnitizer operating

nearby... why would they?

 

[DarkMatter]

On Mon, 29 Dec 2003 20:00:27 -0600, Jim Adney <jadney@vwtype3.org>
Gave us:

On Sun, 28 Dec 2003 16:44:48 -0800 Watson A.Name - "Watt Sun, Dark
Remover" <alondra101@hotmail.com> wrote:

I was watching the meter stick wiggle, and the
thought occurred to me, maybe this meter has been in use for 30+
years, but usually it's powered up and stays pretty much in one place.
But I'm keeping it moving back and forth continuously. I'm wondering
if these d'Arsonval meter movements ever wear out, or get gummed up.
I think they're not lubricated so that shouldn't happen. But with
jewels, what's the lifetime of the movement?

If it's actually a jewelled movement then there is likely some finite,
but large, lifetime. If it's a taut-band movement then I'd expect the
lifetime to be virtually infinite.

The difference between d'arsonval and taut band is the actuation of
the needle, not the support bearing(s). Any mechanical meter movement
that I know of has jeweled bearings, taut band or otherwise

D'arsonval utilizes magnetism, and taut band utilizes thermal
expansion constants. The taut band is more accurate as it is directly
attached to the needle. Magnetism is a bit more spongy, and therefore
can exhibit error prone operation, with less linearity through its
range. The taut band is repeatable through years of service (with
calibration), and being directly attached to the needle, has near zero
error through it's range, and a higher degree of linearity precision.

 

On 28 Dec 2003 22:20:04 -0500, Sam Goldwasser <sam@saul.cis.upenn.edu>
wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.

What exactly does using jewels mean? Obviously they use some sort of
diamond or other "rock", but where and how?
I never understood this ????

Thanks
George

 

[Watson A.Name - "Watt Sun]

In article <3ff0f567$0$4753$61fed72c@news.rcn.com>, cfharris@erols.com
mentioned...

Consider that pocket watches use a very similar jeweled bearing on
their balance wheel. The balance wheel rotates a few hundred degrees
5 times per second. Pocket watches are typically serviced every other
year. They last for hundreds of years.... and yes, unlike a meter,
they are oiled.

Your meter rotates a maximum of 60 degrees, typically. It would have
to go zero to full scale 5 times per second to get even close to a
pocket watch's bearing activity.

-Chuck Harris

Jim Adney wrote:
On Sun, 28 Dec 2003 16:44:48 -0800 Watson A.Name - "Watt Sun, Dark
Remover" <alondra101@hotmail.com> wrote:


I was watching the meter stick wiggle, and the
thought occurred to me, maybe this meter has been in use for 30+
years, but usually it's powered up and stays pretty much in one place.
But I'm keeping it moving back and forth continuously. I'm wondering
if these d'Arsonval meter movements ever wear out, or get gummed up.
I think they're not lubricated so that shouldn't happen. But with
jewels, what's the lifetime of the movement?


If it's actually a jewelled movement then there is likely some finite,
but large, lifetime. If it's a taut-band movement then I'd expect the
lifetime to be virtually infinite.

Hey, thanks, I never thought about comparing the meter movement to a
balance wheel in a clock/watch. But then ever since the late '60s
I've been using watches that don't have a balance wheel. ;-)

I found a digital watch movement out on the street the other day. Bit
rusted from the rain. I'll have to take the batt out and see if it
will still work.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

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that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
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[Watson A.Name - "Watt Sun]

In article <ssf2vvsc0l612oaub8eos2i0vimo162gt2@4ax.com>,
george@myfarm.com mentioned...

On 28 Dec 2003 22:20:04 -0500, Sam Goldwasser <sam@saul.cis.upenn.edu
wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.


What exactly does using jewels mean? Obviously they use some sort of
diamond or other "rock", but where and how?
I never understood this ????

Thanks
George

Sapphire or ruby? I forget. Here's a FAQ I found:
http://www.oris.ch/english/faq.htm
Skip down to the paragraph 4th from the bottom.


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Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
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[Watson A.Name - "Watt Sun]

In article <MPG.1a5afca46b575611989ad2@news.dslextreme.com>, Watson
A.Name - "Watt Sun, Dark Remover" <alondra101@hotmail.com>
mentioned...

In article <ssf2vvsc0l612oaub8eos2i0vimo162gt2@4ax.com>,
george@myfarm.com mentioned...
On 28 Dec 2003 22:20:04 -0500, Sam Goldwasser <sam@saul.cis.upenn.edu
wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.


What exactly does using jewels mean? Obviously they use some sort of
diamond or other "rock", but where and how?
I never understood this ????

Thanks
George

Sapphire or ruby? I forget. Here's a FAQ I found:
http://www.oris.ch/english/faq.htm
Skip down to the paragraph 4th from the bottom.

HAH! ROTFL! Read the second from the bottom paragraph! Those Swiss
elves don't know the diff between lubricate and duplicate!

--
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###Got a Question about ELECTRONICS? Check HERE First:###
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My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Chuck Harris]

DarkMatter wrote:

The difference between d'arsonval and taut band is the actuation of
the needle, not the support bearing(s). Any mechanical meter movement
that I know of has jeweled bearings, taut band or otherwise

That is incorrect!

The taut-band is a frictionless suspension system for the coil
in the meter.

The biggest advantage of a taut-band suspension over a jeweled bearing
suspension is this lack of friction.... You can make a more sensitive
meter movement with the taut-band system.

D'arsonval utilizes magnetism, and taut band utilizes thermal
expansion constants. The taut band is more accurate as it is directly
attached to the needle. Magnetism is a bit more spongy, and therefore
can exhibit error prone operation, with less linearity through its
range. The taut band is repeatable through years of service (with
calibration), and being directly attached to the needle, has near zero
error through it's range, and a higher degree of linearity precision.

Do a google search on "taut band meter" You will find pictures and
descriptions-a-plenty.

-Chuck Harris

 

[Sam Goldwasser]

george@myfarm.com writes:

What exactly does using jewels mean? Obviously they use some sort of
diamond or other "rock", but where and how?
I never understood this ????

The shaft on which the meter coil is mounted has points at either end
that rotate within a conical cavity in ruby or other similar hard material.

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[Sam Goldwasser]

DarkMatter <DarkMatter@thebarattheendoftheuniverse.org> writes:

The difference between d'arsonval and taut band is the actuation of
the needle, not the support bearing(s). Any mechanical meter movement
that I know of has jeweled bearings, taut band or otherwise

No. It specifically deals with the bearings. Jeweled bearings have
a steel shaft pointed at both ends rotating within a concave cavity in a
ruby or other similar hard bearing material.

A taut band movement suspends the coil and needle on a very thing
tensioned steel band which both provides the electrical connections
and restoring force. There is no static friction with such a device.

These are both D'Arsonval - coil in magnetif field - movements.

There are also other types of meters but the references in this thread
all refer to these types.

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D'arsonval utilizes magnetism, and taut band utilizes thermal
expansion constants. The taut band is more accurate as it is directly
attached to the needle. Magnetism is a bit more spongy, and therefore
can exhibit error prone operation, with less linearity through its
range. The taut band is repeatable through years of service (with
calibration), and being directly attached to the needle, has near zero
error through it's range, and a higher degree of linearity precision.

 

[DarkMatter]

On Tue, 30 Dec 2003 03:06:31 -0600, george@myfarm.com Gave us:

On 28 Dec 2003 22:20:04 -0500, Sam Goldwasser <sam@saul.cis.upenn.edu
wrote:

Older meters use jeweled movements and yes they probably do wear
out. I've never seen one fail due to worn bearings. Usually
it is from mechanical or electrical abuse.


What exactly does using jewels mean? Obviously they use some sort of
diamond or other "rock", but where and how?
I never understood this ????

Thanks
George

When one has a shaft that needs to be able to turn very freely, and
said shaft is so small that normal bearing of the type used on bigger
shafts wont work, a small cup shaped bearing, made from a hard
crystalline material has a long life, high precision, and the pin ends
of the shaft do not have a high degree of friction on them.

A shaft placed on a metal hole would wear, and wobble badly after a
short period of action, and would also likely bind in operation.

Jeweled bearings on small shafts like instrumentation or watches and
clocks makes for years of dependable maintenance free service for the
shaft.

A jeweled bearing can last hundreds of years. The only thing that
will or can wear is the shaft pin end itself, as the bearing is of a
much harder media.

 

[DarkMatter]

On 30 Dec 2003 08:22:55 -0500, Sam Goldwasser <sam@saul.cis.upenn.edu>
Gave us:

DarkMatter <DarkMatter@thebarattheendoftheuniverse.org> writes:

The difference between d'arsonval and taut band is the actuation of
the needle, not the support bearing(s). Any mechanical meter movement
that I know of has jeweled bearings, taut band or otherwise

No. It specifically deals with the bearings. Jeweled bearings have
a steel shaft pointed at both ends rotating within a concave cavity in a
ruby or other similar hard bearing material.

I know what a jeweled bearing is.