Today's Message Index:
----------------------
1. 06:34 AM - Re: Duel engines gauges (Robert L. Nuckolls, III)
2. 08:51 AM - Re: Contactors (Robert L. Nuckolls, III)
3. 10:03 AM - Re: Contactors (Richard E. Tasker)
4. 10:51 AM - Re: Contactors (Robert L. Nuckolls, III)
5. 04:19 PM - Re: Duel engines gauges (JOHN TIPTON)
Message 1
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| Subject: | Re: Duel engines gauges |
At 04:58 PM 4/7/2011, you wrote:
>Hi
>
>If I use a duel CHT gauge and a duel EGT gauge (i.e. both are two
>needle instruments), would properly configured 'double pole
>changeover' switch work, to monitor the front 2 cylinders , or the
>rear 2 cylinders
I presume we're talking about thermocouple
instruments. You can do as you've proposed.
Just make sure each thermocouple pathway
gets the same 'pollution' of parasitic
thermocouples so that their effects cancel
each other. Review chapter on temperature
measurement in the 'Connection.
Bob . . .
Message 2
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At 11:38 PM 4/7/2011, you wrote:
><retasker@optonline.net>
>
>Unless I am mistaken the S701 can CARRY the starting current but is
>not designed to make or break (close or open) with the high starting
>current. The S702 is specifically designed to make or break with
>the high starting current.
Right on . . . The S701 draws just under 1A of
current, is designed for continuous duty operations
and is rated to SWITCH only 70A. It has relatively
large area, lower pressure contacts.
http://www.aeroelectric.com/Pictures/Contactors/S701-1b.jpg
The S702 draws 3-5A, gets destructively hot if you
leave it on too long and is rated to SWITCH hundreds
of amps. It features low area, high pressure contacts
http://www.aeroelectric.com/Pictures/Contactors/S702-1a.jpg
They are entirely different breeds of cat crafted
for specific applications.
Having said all that, know that a contactor, relay or
switch that is CONTROLLING currents many times the rated
value WILL perform to some level. In fact, you may
well achieve 'satisfactory performance' from an S701-style
contactor in a starter control application. It's service
life would be reduced to maybe 1-10% of rated . . . but
if that number is still 500-1000 cranking events . . .
how might it matter to you?
Bottom line is that using the S701 in this manner is
simply not the-best-we-know-how-to-do with components
having similar costs. Further, it is not a recipe for
disaster or even severe spikes in cost-of-ownership. So
if you're willing to experiment, then let us know how
it works out.
Bob . . .
Message 3
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While I have no experience using one as a starter contactor, I think I
might be concerned that the S701 contacts could end up welded together
if the return spring is not heavy enough (depending on the particular
starter and engine combination).
Dick Tasker
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 11:38 PM 4/7/2011, you wrote:
>> <retasker@optonline.net>
>>
>> Unless I am mistaken the S701 can CARRY the starting current but is
>> not designed to make or break (close or open) with the high starting
>> current. The S702 is specifically designed to make or break with the
>> high starting current.
>
> Right on . . . The S701 draws just under 1A of
> current, is designed for continuous duty operations
> and is rated to SWITCH only 70A. It has relatively
> large area, lower pressure contacts.
>
> http://www.aeroelectric.com/Pictures/Contactors/S701-1b.jpg
>
>
> The S702 draws 3-5A, gets destructively hot if you
> leave it on too long and is rated to SWITCH hundreds
> of amps. It features low area, high pressure contacts
>
> http://www.aeroelectric.com/Pictures/Contactors/S702-1a.jpg
>
> They are entirely different breeds of cat crafted
> for specific applications.
>
> Having said all that, know that a contactor, relay or
> switch that is CONTROLLING currents many times the rated
> value WILL perform to some level. In fact, you may
> well achieve 'satisfactory performance' from an S701-style
> contactor in a starter control application. It's service
> life would be reduced to maybe 1-10% of rated . . . but
> if that number is still 500-1000 cranking events . . .
> how might it matter to you?
>
> Bottom line is that using the S701 in this manner is
> simply not the-best-we-know-how-to-do with components
> having similar costs. Further, it is not a recipe for
> disaster or even severe spikes in cost-of-ownership. So
> if you're willing to experiment, then let us know how
> it works out.
>
>
> Bob . . .
>
>
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Message 4
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At 12:58 PM 4/8/2011, you wrote:
><retasker@optonline.net>
>
>While I have no experience using one as a starter contactor, I think
>I might be concerned that the S701 contacts could end up welded
>together if the return spring is not heavy enough (depending on the
>particular starter and engine combination).
A perceptive concern sir!
Bob . . .
Message 5
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| Subject: | Re: Duel engines gauges |
Bob
Thank you
John
----- Original Message -----
From: Robert L. Nuckolls, III
To: aeroelectric-list@matronics.com
Sent: Friday, April 08, 2011 1:29 PM
Subject: Re: AeroElectric-List: Duel engines gauges
At 04:58 PM 4/7/2011, you wrote:
Hi
If I use a duel CHT gauge and a duel EGT gauge (i.e. both are two
needle instruments), would properly configured 'double pole changeover'
switch work, to monitor the front 2 cylinders , or the rear 2 cylinders
I presume we're talking about thermocouple
instruments. You can do as you've proposed.
Just make sure each thermocouple pathway
gets the same 'pollution' of parasitic
thermocouples so that their effects cancel
each other. Review chapter on temperature
measurement in the 'Connection.
Bob . . .
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