I recently was high bidder for a NOS, 6 volt, Hobbs meter. I served my
apprenticeship at Stewart-Warner so what can I say? Just could not resist after
seeing the old familiar face.
I want to put the meter in the panel of an aircraft I am building, said
aircraft has a 12 volt system.
What I dont know about electronics and electricty would fill a library so how
do I get from 12 volts to 6 volts?
Seems I remember when we used to convert the old VW beetles to 12 volts, we
kept the 6 volt starter, changed the lights but kept the windshield washer
motor 6 volts. How did we do that?
Anyway, all help will be appreciated.

Warren

In article , Whunicut says...

I recently was high bidder for a NOS, 6 volt, Hobbs meter.

Gads. I have no idea what a Hobbs meter is. You got one
on this old goat. Is it an hourmeter?

Any time you want to go from 12 to 6 volts in a small
instrument (if that's what this is) then the best way
is to see what the current draw is, and use an appropriate
solid state semiconductor regulator chip, in this case it
would take in 12 volts and produce 6 volts regulated.

The sticky spot is to see how much power the regulator
will be dissipating, and if it's a lot, then to drop
some of the power in a series resistor.

Do you have any idea of the current draw?

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

In article ,
jim rozen wrote:

In article , Whunicut says...

I recently was high bidder for a NOS, 6 volt, Hobbs meter.

Gads. I have no idea what a Hobbs meter is. You got one
on this old goat. Is it an hourmeter?

Any time you want to go from 12 to 6 volts in a small
instrument (if that's what this is) then the best way
is to see what the current draw is, and use an appropriate
solid state semiconductor regulator chip, in this case it
would take in 12 volts and produce 6 volts regulated.

The sticky spot is to see how much power the regulator
will be dissipating, and if it's a lot, then to drop
some of the power in a series resistor.

Do you have any idea of the current draw?

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

I think Hobbs meter winding coil's draw a good bit of current every 30
seconds or so in the wind cycle, maybe a 2 or 3 millisecond pulse.

Seems I remember then having a wide operational voltage range, like 4 to
40V or something like that... I'm talking about the old mechanical ones
here, not the newer Quartz or digital's.

Erik

On 06 Jul 2004 20:38:57 GMT, S (Whunicut) wrote:

||I recently was high bidder for a NOS, 6 volt, Hobbs meter. I served my
||apprenticeship at Stewart-Warner so what can I say? Just could not resist
after
||seeing the old familiar face.
||I want to put the meter in the panel of an aircraft I am building, said
||aircraft has a 12 volt system.
||What I dont know about electronics and electricty would fill a library so how
||do I get from 12 volts to 6 volts?
||Seems I remember when we used to convert the old VW beetles to 12 volts, we
||kept the 6 volt starter, changed the lights but kept the windshield washer
||motor 6 volts. How did we do that?
||Anyway, all help will be appreciated.

Auto parts stores used to keep voltage reducers for just that purpose. You
needed one or more depending on draw. This application would just need one.

Still in the catalog and on the shelf. We sold 134 of them last week.
Who'da thought it?

Borg Warner number is VR1.
1.5 ohm resistance for up to 4 amp load.
Basically a wound-wire resister in a ceramic shell

VR2 is the same thing with a mounting bracket
Any parts store should be able to cross it to their brand.
Cost is about $10
Texas Parts Guy

Whunicut wrote:

I recently was high bidder for a NOS, 6 volt, Hobbs meter.

so how
do I get from 12 volts to 6 volts?

For the amount of current you are talking about, put a 6.2 volt Zener
diode with the requisite power rating (probably written on the meter, if
not you will have to measure the current draw) in series with the meter.

Kevin Gallimore


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I recently was high bidder for a NOS, 6 volt, Hobbs meter.

Gads. I have no idea what a Hobbs meter is. You got one
on this old goat. Is it an hourmeter?

Any time you want to go from 12 to 6 volts in a small
instrument (if that's what this is) then the best way
is to see what the current draw is, and use an appropriate
solid state semiconductor regulator chip, in this case it
would take in 12 volts and produce 6 volts regulated.

The sticky spot is to see how much power the regulator
will be dissipating, and if it's a lot, then to drop
some of the power in a series resistor.

Do you have any idea of the current draw?

Jim

Dern it, I should have explained better.
Yes, it is an hourmeter. Round and made to fit in an instrument panel hole
approx 2 1/8 dia.
Nope, have no idea what the current draw is. How do I measure that?
Semi conductor chip....is this what is called a zener by someone else?

Thanks,
Warren

I think Hobbs meter winding coil's draw a good bit of current every 30
seconds or so in the wind cycle, maybe a 2 or 3 millisecond pulse.

Seems I remember then having a wide operational voltage range, like 4 to
40V or something like that... I'm talking about the old mechanical ones
here, not the newer Quartz or digital's.

Erik

Well, this is certainly the old mechanical type. Probably a dumb question but
here goes. If it just spikes from 4 to 4o volts every 3 minutes or so, why do I
have to do anything? Wouldn`t 12 volts work?

Also, the papers that came with it mention models without the instant stop
feature would run on for up to 3 minutes after being turned off.
Verifies your statement above.

Warren

Auto parts stores used to keep voltage reducers for just that purpose. You
needed one or more depending on draw. This application would just need one.

Still in the catalog and on the shelf. We sold 134 of them last week.
Who'da thought it?

Borg Warner number is VR1.
1.5 ohm resistance for up to 4 amp load.
Basically a wound-wire resister in a ceramic shell

VR2 is the same thing with a mounting bracket
Any parts store should be able to cross it to their brand.
Cost is about $10
Texas Parts Guy

Thanks Texas Parts Guy. Just proves they made some tough 6 volt cars in the
Good Old Days!

Warren

For the amount of current you are talking about, put a 6.2 volt Zener
diode with the requisite power rating (probably written on the meter, if
not you will have to measure the current draw) in series with the meter.

Kevin Gallimore

Not on the meter or in the literature is there anything about the power rating.
Other than 6 volts.
If the meter spikes every 3 minutes or so, how can I measure the spike? Or do I
have to?

Thanks,
Warren

Whunicut wrote:

Not on the meter or in the literature is there anything about the power rating.
Other than 6 volts.
If the meter spikes every 3 minutes or so, how can I measure the spike? Or do I
have to?

You would need to know what type of Hobbs meter it is.
You could ask Hobbs:

http://content.honeywell.com/sensing...p/cat1_hr5.asp

For your purposes, however, a one watt Zener would work with any
Hobbs-type meter I've seen, be it electronic or electromechanical. But
I would not tell someone else to use it without measuring the current.
Put a one Ohm resistor in series with the Hobbs meter. Apply 12 volts.
Measure the voltage across the resistor. You will read current in Amps.
Alternatively, you could use an ampmeter. Assuming it is an averaging
meter, at DC: Volts(12)*Amps(what you measure)= average Watts. Pick a
power rating for the Zener that is greater than the power you measure.
Zener diodes are available at Digi-Key.
Here is a typical data sheet:

http://rocky.digikey.com/WebLib/Micr...8A-1N4764A.pdf

When's my ride?

Kevin Gallimore




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In article ,
S (Whunicut) wrote:

I think Hobbs meter winding coil's draw a good bit of current every 30
seconds or so in the wind cycle, maybe a 2 or 3 millisecond pulse.

Seems I remember then having a wide operational voltage range, like 4 to
40V or something like that... I'm talking about the old mechanical ones
here, not the newer Quartz or digital's.

Erik

Well, this is certainly the old mechanical type. Probably a dumb question but
here goes. If it just spikes from 4 to 4o volts every 3 minutes or so, why do
I
have to do anything? Wouldn`t 12 volts work?

Also, the papers that came with it mention models without the instant stop
feature would run on for up to 3 minutes after being turned off.
Verifies your statement above.

Warren

Hmmm... it just draws a brief pulse of current periodically when it
winds, and the rest of the time is electrically 'dormant'.

What I meant, is I 'think' they (or some models anyway) were ok for use
with a supply voltage in the range of 4 to 40 Volts... or some big range
like that. I wouldn't bet my life on it though.

I bet you could Google up info about your particular model...

Funny, I had an old (NOS, less than an hour total time showing) square
Hobbs meter someone gave me years ago.... sold it on eBay in the last
year or so. Got a lot of bids on it too. I had some GREAT, super sharp
macro photos in the ad... it really makes a difference.

Good Luck!

Erik

In article , axolotl says...

For the amount of current you are talking about, put a 6.2 volt Zener
diode with the requisite power rating (probably written on the meter, if
not you will have to measure the current draw) in series with the meter.

I would probably go with a three terminal regulator like
a 7806 for this application. Though, the zener might work.

He could also just put 7 or 8 silicon diodes in series
to drop the six volts.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

How about either of these?

http://www.jcwhitney.com/autoparts/P...atalogId-10101

http://www.jcwhitney.com/autoparts/P...atalogId-10101

Best Regards,
Keith Marshall


"Even if you are on the right track, you'll
get run over if you just sit there."
- Will Rogers (1879-1935).


"Whunicut" wrote in message
...
I recently was high bidder for a NOS, 6 volt, Hobbs meter. I served my
apprenticeship at Stewart-Warner so what can I say? Just could not resist
after
seeing the old familiar face.
I want to put the meter in the panel of an aircraft I am building, said
aircraft has a 12 volt system.
What I dont know about electronics and electricty would fill a library so
how
do I get from 12 volts to 6 volts?
Seems I remember when we used to convert the old VW beetles to 12 volts,
we
kept the 6 volt starter, changed the lights but kept the windshield washer
motor 6 volts. How did we do that?
Anyway, all help will be appreciated.

Warren

First, I'll answer your other question, about converting 6v VW's to 12
volts. I recall the VW mechanics telling me how they left the 6v starter,
etc., in the car, so the engine would REALLY spin during the cranking. They
also applied the full 12 volts to the 6v ignition coil, during starting
only, to get a REALLY hot spark.

If the Hobbs meter draws current in short bursts, chances are you could use
the full 12 volts. If the wind-up is self limiting, the pulses would be
shorter than standard, and probably work perfectly.

If you want to be really safe, you could wire some resistance in series with
the meter. Use enough so the meter doesn't work, and then keep reducing it
until it sounds like it is pulsing normally. That would be a way to do it
if you don't have a meter, or if your meter won't deal with short pulses
(most of them won't.)

I have one of those meters on my 56 porsche. if you really want to regulate
it to 6V, use a 7805 chip and a capacitor - that will give you very
accurately regulated 5V (which will be fine with the meter) for about 50
cents.

"Whunicut" wrote in message
...
I recently was high bidder for a NOS, 6 volt, Hobbs meter. I served my
apprenticeship at Stewart-Warner so what can I say? Just could not resist
after
seeing the old familiar face.
I want to put the meter in the panel of an aircraft I am building, said
aircraft has a 12 volt system.
What I dont know about electronics and electricty would fill a library so
how
do I get from 12 volts to 6 volts?
Seems I remember when we used to convert the old VW beetles to 12 volts,
we
kept the 6 volt starter, changed the lights but kept the windshield washer
motor 6 volts. How did we do that?
Anyway, all help will be appreciated.

Warren

In article m, william_b_noble
says...

I have one of those meters on my 56 porsche. if you really want to regulate
it to 6V, use a 7805 chip and a capacitor - that will give you very
accurately regulated 5V (which will be fine with the meter) for about 50
cents.

Two capacitors - one on the input and one on the output.
And use a 7806 - which will regulate at +6 volts.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

I would try the 7806 as others have suggested.

Mount it on sheetmetal to serve as a heatsink. The tab is
electrically ground.

It's a low-risk proposition:

They only cost a buck or two at Radio Shack

They're self-protected against burnout. If they overheat they just
shut down

They'll deliver an amp or so until they overheat

If the Hobbs just draws short pulses, it's quite unlikely that the
7806 will overheat.

In article , Don Foreman says...

I would try the 7806 as others have suggested.
....
They only cost a buck or two at Radio Shack

RS will probably not carry the six volt version.
He would have to order that from Newark or Digi-Key
I think.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

To all who replied:
This has been a real learning experience for me. Never heard of a Zener before!
There are many "off the shelf" gismos that will do the job and can get
expensive.
I like to tinker and experiment so I am going with

1. resistor of; 1.99 ohms, 32.16 watts.
2. Zener of 6v.24.12 watts.

I got these numbers at the Zener diode selector

My meter would not register the spike for the rewind stage, so I hooked the
Hobbs up to the battery charger switched to 6v in and 6amp. When the spike
came, the meter jumped about 1.5 amps. I used 2000 mA for the diode selector.

And to Kevin Gallimore...probably be a year. (90% done and 90% to go) But if
you want a ride in the Marquart Charger, come on down and we will bore some
holes in the sky!

Regards and Thanks to All.
Warren

On 07 Jul 2004 20:58:06 GMT, S (Whunicut) wrote:

||To all who replied:
||This has been a real learning experience for me. Never heard of a Zener
before!
||There are many "off the shelf" gismos that will do the job and can get
||expensive.
||I like to tinker and experiment so I am going with
||
||1. resistor of; 1.99 ohms, 32.16 watts.
||2. Zener of 6v.24.12 watts.
||
|| I got these numbers at the Zener diode selector
||
||My meter would not register the spike for the rewind stage, so I hooked the
||Hobbs up to the battery charger switched to 6v in and 6amp. When the spike
||came, the meter jumped about 1.5 amps. I used 2000 mA for the diode selector.
||
||And to Kevin Gallimore...probably be a year. (90% done and 90% to go) But if
||you want a ride in the Marquart Charger, come on down and we will bore some
||holes in the sky!
||
||Regards and Thanks to All.
||Warren

Nice looking aircraft, Warren.
Do you have it apart, or what?

Texas Parts Guy

||you want a ride in the Marquart Charger, come on down and we will bore some
||holes in the sky!
||
||Regards and Thanks to All.
||Warren

Nice looking aircraft, Warren.
Do you have it apart, or what?

Texas Parts Guy

No. Dont have the Charger apart. Flew her some yesterday. Gotta keep the
condensation out of the oil, you know. )
I`m building another of my own design which is an enclosed high wing STOL. Got
tired of freezing my butt in the wintertime sitting in that open `pit.

Regards,
Warren

On Wed, 07 Jul 2004 02:34:18 GMT, "Leo Lichtman"
wrote:

First, I'll answer your other question, about converting 6v VW's to 12
volts. I recall the VW mechanics telling me how they left the 6v starter,
etc., in the car, so the engine would REALLY spin during the cranking. They
also applied the full 12 volts to the 6v ignition coil, during starting
only, to get a REALLY hot spark.

In the old 6v VWs, replacing the 6v starter motor with a 12v one was
more work than it was worth. The diameter of the starter motor shaft
was different, meaning you had to replace the bearing in the transaxle
(transmission) case. Besides, the 6v starters ran fine (meaning
*fast* g) on 12v! I did run a 12v coil, though.

The windshield wiper motor was a bit of a pain. The 6v and 12v wipers
parked on opposite sides of the car, so a simple swap wouldn't work.
Most people went with the dropping resistor, although I managed to
mate a 12v motor to a 6v wiper gearbox. This, along with replacing
the wiper switch (and running one more wire), gave you the 2 ! wiper
speeds!

The turn signal relay was worse. Running a 6v relay on 12v produced a
faster 'blink rate' (until the relay welded itself). DAHMKIT! It
didn't help that VW changed the flasher wiring (and relay) almost
every year (often combining too many things into the same 'relay'
spelled $$$).

The 6v horn worked fine loud! on 12v. The fuel guage was still
mechanical (no sending unit to worry about). The radio needed to be
changed, but then again, who wanted to listen to the stock AM radio?

Ok, let's see. What else .. Ok, all the light bulbs (headlights,
taillights, turn signals, brake lights, parking lights, dash lights,
dome lights, idiot lights, etc.). You *know* you're going to forget
at least *one* of them.

Ok, other than the headlight switch and the headlight/highbeam relay,
I think that's it.

Ah, memories .....

solid state semiconductor regulator chip, in this case it

Dern it, I should have explained better.
Yes, it is an hourmeter. Round and made to fit in an instrument panel hole
approx 2 1/8 dia.
Nope, have no idea what the current draw is. How do I measure that?
Semi conductor chip....is this what is called a zener by someone else?

A zener diode and a voltage regulator are not the same. If you had a
zener diode rated at 6 volts for the avalanche point, then it is
guaranteed to have a voltage drop of 6 volts from lead to lead, if you
hook it up properly. Because of this when you hook it up in series like
the other guy described, 12-6 =6

The voltage regulator is the much more sophisticated way of doing it. If
you use one of those, the voltage will always be 6 volts no matter what.

The trouble with both parts is getting one big enough to handle the current.

-Jonathan

Johnathan - may I humbly suggest that you are mistaken. Consider either
approach that provides a 6V feed to the hobbs meter. Put a 30 mdf capacitor
across the meter terminals. when the contacts close to energize the wind
solenoid (that's how the mechanism works on the one I'm familar with), the
current is provided predominantly by the capacitor. The 7806 (or the more
common 7805) will supply 3 amps, which is probably enough by itself, but the
capacitor will give it an added surge capability.


"Jonathan Ward" wrote in message
...

solid state semiconductor regulator chip, in this case it

Dern it, I should have explained better.
Yes, it is an hourmeter. Round and made to fit in an instrument panel
hole
approx 2 1/8 dia.
Nope, have no idea what the current draw is. How do I measure that?
Semi conductor chip....is this what is called a zener by someone else?

A zener diode and a voltage regulator are not the same. If you had a
zener diode rated at 6 volts for the avalanche point, then it is
guaranteed to have a voltage drop of 6 volts from lead to lead, if you
hook it up properly. Because of this when you hook it up in series like
the other guy described, 12-6 =6

The voltage regulator is the much more sophisticated way of doing it. If
you use one of those, the voltage will always be 6 volts no matter what.

The trouble with both parts is getting one big enough to handle the
current.

-Jonathan

As much as I enjoy seeing what sort of suicide devices people will
cobble together and bolt to an aircraft... I feel almost obligated to
mention that you can find brand new 12v Hobbs hourmeters on E-bay for about
$20.
http://cgi.ebay.com/ebaymotors/ws/eB...tego ry=46100






"Whunicut" wrote in message
...
To all who replied:
This has been a real learning experience for me. Never heard of a Zener
before!
There are many "off the shelf" gismos that will do the job and can get
expensive.
I like to tinker and experiment so I am going with

1. resistor of; 1.99 ohms, 32.16 watts.
2. Zener of 6v.24.12 watts.

I got these numbers at the Zener diode selector

My meter would not register the spike for the rewind stage, so I hooked
the
Hobbs up to the battery charger switched to 6v in and 6amp. When the spike
came, the meter jumped about 1.5 amps. I used 2000 mA for the diode
selector.

And to Kevin Gallimore...probably be a year. (90% done and 90% to go) But
if
you want a ride in the Marquart Charger, come on down and we will bore
some
holes in the sky!

Regards and Thanks to All.
Warren

Jonathan, this is pretty close, but could some clarification...

A zener diode IS a primitive voltage regulator. Normally, zener diodes are
wired in parallel with the load, and shunt excess current in order to "clamp"
the input voltage at the zener rating. The power supply voltage must be greater
than the zener diode's breakdown rating, and have a current-limiting resistor
wired in series with the zener diode and the load to drop the power supply
voltage to the zener's value. It's this shunted current, (oddly) called the
"zener current" BG that determines the wattage of the diode. So if you're
using the zener to clamp the voltage at 6V, the device draws 3 amps, and the
anticipated zener current is 0.5 amps, you'd need a zener diode rated for at
least 3 watts. (6V X 0.5A = 3W) Note too that a zener diode can't work if the
current through the limiting resistor causes the voltage at the top of the
zener diode to drop below its rated reverse-bias breakdown value. If this
happens, the zener current drops to 0 and whatever the voltage is at the
limiting resistor's junction with the zener diode is the voltage applied to the
load.

On the other hand a voltage regulator, for all practical purposes, IS the power
supply to the load, and its power rating is determined solely by the load
current. So if we have a 6V device that draws 3 amps, our 7806 voltage
regulator must be rated for at least 18 watts. You are correct in stating that
the voltage applied to the load device will always be 6V, regardless of the
current drawn by the load. (Ironically, the 78-series voltage regulator chips
use zener diode networks internally to provide their reference voltages.)

This link provides an excellent explanation of zener diodes and has schematics
of what I've tried to explain above:

http://hyperphysics.phy-astr.gsu.edu...ids/zener.html

HTH.

Respectfully,
Scotty

*** And now, we return to our regularly-scheduled program... ***

"Jonathan Ward" wrote:

solid state semiconductor regulator chip, in this case it

Dern it, I should have explained better.
Yes, it is an hourmeter. Round and made to fit in an instrument panel
hole approx 2 1/8 dia.
Nope, have no idea what the current draw is. How do I measure that?
Semi conductor chip....is this what is called a zener by someone else?

A zener diode and a voltage regulator are not the same. If you had a
zener diode rated at 6 volts for the avalanche point, then it is
guaranteed to have a voltage drop of 6 volts from lead to lead, if you
hook it up properly. Because of this when you hook it up in series like
the other guy described, 12-6 =6

The voltage regulator is the much more sophisticated way of doing it. If
you use one of those, the voltage will always be 6 volts no matter what.

The trouble with both parts is getting one big enough to handle the
current.

-Jonathan

On Thu, 8 Jul 2004 10:38:24 -0500, "David Courtney"
wrote:

|| As much as I enjoy seeing what sort of suicide devices people will
||cobble together and bolt to an aircraft... I feel almost obligated to
||mention that you can find brand new 12v Hobbs hourmeters on E-bay for about
||$20.
||http://cgi.ebay.com/ebaymotors/ws/eB...tego ry=46100

The OP has a 12V Hobbs meter.
Did you find a 6-volt model while you were there?


Texas Parts Guy

As much as I enjoy seeing what sort of suicide devices people will
cobble together and bolt to an aircraft... I feel almost obligated to
mention that you can find brand new 12v Hobbs hourmeters on E-bay for about
$20.

Well, I never knew hourmeters were some sort of "suicide device". I will watch
this "device" very closely and if it shows any sign of committing Hari-Kari,
out it goes!

Yep, the new 12 volt meters are all state-of-of-the-art plastic and have the
clock works you have in the wall clock in the garage.
The ancient meter I have is all metal, has a wind up clock mechanism and a
familiar face from my younger days.
I would not trade it for 10 of the new
, "quartz" jobs.

BTW, last I heard, I still have the right to "cobble together" anything I
please and bolt it onto an experimental aircraft, auto, boat or kite and
"experiment " to my hearts content. And if you are entertained by this, we both
win.)

Warren