Today's Message Index:
----------------------
1. 04:25 AM - Re: Wherefore loadmeters? (Sam Hoskins)
2. 06:22 AM - Re: Wherefore loadmeters? (Robert McCallum)
3. 07:15 AM - Re: Wherefore loadmeters? (kesleyelectric)
Message 1
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| Subject: | Re: Wherefore loadmeters? |
Another question about load meters.
Most ammeters display +/- amps; charge/discharge.
Why do load meters not display +/- percent?
Should a panel contain both a load meter and an ammeter, or can we get away
with strictly a load meter?
Thanks.
Sam
On Nov 16, 2007 7:53 AM, Robert L. Nuckolls, III <nuckolls.bob@cox.net>
wrote:
> nuckolls.bob@cox.net>
>
> At 05:39 PM 11/15/2007 -0600, you wrote:
>
> >Does anyone know where Bob's articles on load meters are? I thought it
> >might be in Chapter 7, but I couldn't find it.
> >
> >Sam
>
> There are no articles specific to the topic
> of loadmeters. In general, these are generic
> ammeters but instead of calibrating the scale
> plate in amperes, they are calibrated in percent
> with 100% being full scale. See:
>
> http://www.aeroelectric.com/Pictures/Instruments/Loadmeter_2.jpg
>
> http://www.aeroelectric.com/Pictures/Instruments/loadmeter.jpg
>
> https://matronics.com/aeroelectric/Catalog/9007-120-1_Loadmeter.jpg
>
>
> The handy thing about this calibrating convention
> is that a single instrument can be used with
> any size alternator or generator. The full
> scale sensitivity of instrument in amperes is
> set by the size of the companion shunt. See:
>
> http://www.aeroelectric.com/Pictures/Instruments/20-50_Shunt.jpg
>
> A 20A shunt goes with alternators like the SD-20
> and the instrument reads full scale when 100%
> of the 20A machine is being taxed. It follows that
> other sized alternators are monitored with the
> appropriately sized shunt on the same instrument.
>
> When the system is fitted with more than one
> alternator, a single instrument can be switched
> between the two sources, each fitted with the
> appropriate sized shunt; wired as described here:
>
> https://matronics.com/aeroelectric/Catalog/AEC/9007/AEC9007-700.pdf
>
> Bob . . .
>
>
> ----------------------------------------)
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ----------------------------------------
>
>
--
Sam Hoskins
www.MistakeProofing.Net
www.MistakeProofing.net/blog/
618-967-0016 ph.
312-212-4086 fax
Message 2
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| Subject: | Re: Wherefore loadmeters? |
----- Original Message -----
From: Sam Hoskins
To: aeroelectric-list@matronics.com
Sent: Saturday, November 17, 2007 7:21 AM
Subject: Re: AeroElectric-List: Wherefore loadmeters?
Another question about load meters.
Most ammeters display +/- amps; charge/discharge.
Only battery ammeters function this way. i.e. measuring current into
or out of the battery.
Why do load meters not display +/- percent?
Because you are normally measuring the amount of load on the
alternator, which under all "normal" circumstances can only be positive.
(negative flow, i.e. feeding power INTO the alternator can only occur
with certain types of alternator failure)
Should a panel contain both a load meter and an ammeter, or can we get
away with strictly a load meter?
Neither are necessary. The most useful "meter" is a voltmeter, and
even it isn't necessary. All you really care about is whether or not
your alternator is carrying the necessary loads and keeping the battery
charged. If it is then the system voltage will be maintained at the
regulator setting (14+ volts) If it isn't the voltage will sag, your low
voltage warning will inform you of the fact, and you employ your load
reduction procedures (switch to your endurance buss with its
predetermined minimal loads) to fly to your destination where you
troubleshoot the problem.
Thanks.
You're welcome
Sam
Bob McC
Message 3
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| Subject: | Wherefore loadmeters? |
Sam,
The conventional battery ammeter measures current going into the battery
under charging conditions (+ reading), or flowing out of the battery (-
reading) when the alternator is not supporting the load. When the
alternator is supporting the load and the battery is fully charged, the
ammeter will show very little deflection.
The load meter measures only alternator output,regardless of whether that
output is supporting the load or charging the battery.
Tom Barter
Kesley, IA
Avid Magnum
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Sam
Hoskins
Sent: Saturday, November 17, 2007 6:22 AM
Subject: Re: AeroElectric-List: Wherefore loadmeters?
Another question about load meters.
Most ammeters display +/- amps; charge/discharge.
Why do load meters not display +/- percent?
Should a panel contain both a load meter and an ammeter, or can we get away
with strictly a load meter?
Thanks.
Sam
On Nov 16, 2007 7:53 AM, Robert L. Nuckolls, III <nuckolls.bob@cox.net>
wrote:
<nuckolls.bob@cox.net>
At 05:39 PM 11/15/2007 -0600, you wrote:
>Does anyone know where Bob's articles on load meters are? I thought it
>might be in Chapter 7, but I couldn't find it.
>
>Sam
There are no articles specific to the topic
of loadmeters. In general, these are generic
ammeters but instead of calibrating the scale
plate in amperes, they are calibrated in percent
with 100% being full scale. See:
http://www.aeroelectric.com/Pictures/Instruments/Loadmeter_2.jpg
http://www.aeroelectric.com/Pictures/Instruments/loadmeter.jpg
<http://www.aeroelectric.com/Pictures/Instruments/loadmeter.jpg>
https://matronics.com/aeroelectric/Catalog/9007-120-1_Loadmeter.jpg
The handy thing about this calibrating convention
is that a single instrument can be used with
any size alternator or generator. The full
scale sensitivity of instrument in amperes is
set by the size of the companion shunt. See:
http://www.aeroelectric.com/Pictures/Instruments/20-50_Shunt.jpg
A 20A shunt goes with alternators like the SD-20
and the instrument reads full scale when 100%
of the 20A machine is being taxed. It follows that
other sized alternators are monitored with the
appropriately sized shunt on the same instrument.
When the system is fitted with more than one
alternator, a single instrument can be switched
between the two sources, each fitted with the
appropriate sized shunt; wired as described here:
https://matronics.com/aeroelectric/Catalog/AEC/9007/AEC9007-700.pdf
<https://matronics.com/aeroelectric/Catalog/AEC/9007/AEC9007-700.pdf>
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
--
Sam Hoskins
www.MistakeProofing.Net
www.MistakeProofing.net/blog/ <http://www.MistakeProofing.net/blog/>
618-967-0016 ph.
312-212-4086 fax
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