Today's Message Index:
----------------------
1. 06:11 AM - Re: Re: Aircraft Tug (ktup122@aol.com)
2. 01:46 PM - Re: OV B-lead Relay (Robert L. Nuckolls, III)
3. 09:11 PM - Re: Aircraft Tug (Bill Bear)
4. 09:17 PM - Re: Aircraft Tug (Bill Bear)
5. 09:18 PM - Re: OV B-lead Relay (Dan Fritz)
6. 09:26 PM - Re: Aircraft Tug (Bill Bear)
7. 09:43 PM - Re: Aircraft Tug (Bill Bear)
8. 10:22 PM - Re: Aircraft Tug (Bill Bear)
9. 11:27 PM - Re: Aircraft Tug (Bill Bear)
Message 1
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| Subject: | Re: Aircraft Tug |
ktup122@aol.com
-----Original Message-----
From: Tom Barter <kesleyelectric@iowatelecom.net>
Sent: Sat, Apr 18, 2020 02:20 PM
Subject: RE: AeroElectric-List: Aircraft Tug
Attached is a photo of an aircraft tug a friend built from a walk behind snow blower with a failed engine. The transmission allows speed control going forward plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com <owner-aeroelectric-list-server@matronics.com> On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject: AeroElectric-List: Aircraft Tug Hello all Im looking at building a 12v battery operated aircraft tug, not a ride on just a walk with. My max aircraft weight will be about 1800 lbs. I am looking for advise on what size motor I will need. There are a few 12v motors for sale on ebay but they are not rated in hp so am not sure of what specs Im looking at. One thought was to use a car starter motor but that is not rated for continuous service but the farthest I will go with the tug is 100 yds and Im not sure if it will cope with that distance. A friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
Message 2
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| Subject: | Re: OV B-lead Relay |
>I'm using an IR alternator as my primary source of electrons on my
>Velocity. I'd like to provide overvoltage protection to include
>a B-Lead disconnect relay. With a 34A continuous normal system
>load, will an automotive cube relay rated at 70A be satisfactory
>in lieu of the normally used "metal can" style battery contactor?
Figure Z24 has been a burr under my intellectual saddle
for over 20 years. It was a rather crude band-aid for
adding ov protection to an internally regulated alternator
where we, as system integrators, had no absolute control
over field excitation voltage of the alternator. This
produces failure modes initiating an uncontrollable
alternator runaway.
B&C's offerings to the OBAM aviation market exploited
the fine craftsmanship of some automotive alternators
by modifying them to accept field excitation from
an external controller. Plane-Power took a slightly
different approach . . . their first offerings retained
the built in regulator but included modifications to
(1) bring field excitation lead out of the alternator
and (2) add crowbar ov protection to that field power
feeder. You can see the crowbar ovm module piggy-backed
onto a P-P alternator in the attached photo.
The common theme for these offerings is MODIFICATION
of an off-the-shelf alternator to effect smooth integration
of the alternator into legacy aircraft system architectures.
Many moons ago, we had some in-depth discussions about
'reliability' of stock automotive products. Admittedly,
modern alternators do demonstrate exceptionally long
service lives. If one is content to hang their hat
on perceived reliability, then putting a stock
automotive alternator on YOUR project meets design
goals.
As a system integrator with a few decades of
experience designing to FMEA protocols, I couldn't
recommend running the stock alternator 'bare footed'.
So how to gracefully unhook the stock automotive
alternator in a runaway condition from the ship's
electrical system?
Breaking the b-lead is the only option. But instead
nailing the tiger's tail to the ground, we're working
on the other end of this flame-throwing beast.
The physical realities for this condition are:
The alternator's field excitation is derived
directly from the b-lead.
So once the b-lead disconnect's from the system
in general and the battery in particular, b-lead
voltage rises exponentially.
That rise is exacerbated by the fact that in
milliseconds after onset of the ov condition,
the alternator will be in full current limited
output with the battery grunting the excess
energy.
When the b-lead is broken, the effect is
like a race horse shot out of the gate on
springs. Voltage goes up, field excitation
goes up, voltage takes off for the moon.
While breaking this pathway will isolate
the alternator from the ship's systems, it
cannot isolate the alternator from itself.
The voltage will rise very rapidly to perhaps
hundreds of volts. This puts alternator
rectifiers and field windings at risk for
failure. It is almost a certainty that
the failed alternator will not enjoy
a gentle outcome for the ov event.
Selection of the disconnect relay is a
bit more problematic than routine
control tasks in the rest of the system.
Our relay must survive a break of this
rapidly rising, robust current source.
Spectacular arcing will most certainly
establish in the gap of spreading contacts.
The relay of choice should have thermally
massive contacts . . . and preferably
be of the double make-break variety.
Further, it the fire doesn't go out,
it's a pretty good idea to pick an
enclosure likely to contain the effects.
The other attached figure speaks to features
in the legacy 'whisky barrel' contactors.
There are two contacts in series for
2x the spreading velocity of a 'relay'.
The contacts are thermally massive
to help conduct heat out of the arc as
the contacts spread. The enclosure is
likely to contain any electrical conflagration
that fails to extinguish.
The short answer to your question is: That
contactor was selected for reasons beyond
the device's ratings. Substitutions are
not recommended.
The elegant answer suggests you modify
your alternator to ground one brush and
bring the other one out to a generic
'ford' regulator as depicted in Z101.
It's not a difficult mod. Best yet, it
reduces energy release in an ov event
to a tiny fraction of that produced by
a b-lead disconnect. No arcs, no flame,
just a little 'click' as the field
breaker opens. No hardware in the alternator
b-lead.
Bob . . .
Message 3
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| Subject: | Re: Aircraft Tug |
Thanks, Tom. Gotta add this one to my to do list.
Bill Bear
> On Apr 19, 2020, at 05:09, ktup122@aol.com wrote:
>
>
>
>
> ktup122@aol.com
>
>
> -----Original Message-----
> From: Tom Barter <kesleyelectric@iowatelecom.net>
> To: aeroelectric-list <aeroelectric-list@matronics.com>
> Sent: Sat, Apr 18, 2020 02:20 PM
> Subject: RE: AeroElectric-List: Aircraft Tug
>
>
> Attached is a photo of an aircraft tug a friend built from a walk behind snow
blower with a failed engine. The transmission allows speed control going forward
plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com>
On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject:
AeroElectric-List: Aircraft Tug Hello
all Im looking at building a 12v battery operated aircraft tug, not a ride on
just a walk with. My max aircraft weight will be about 1800 lbs. I am looking
for advise on what size motor I will need. There are a few 12v motors for sale
on ebay but they are not rated in hp so am not sure of what specs Im looking
at. One thought was to use a car starter motor but that is not rated for
continuous service but the farthest I will go with the tug is 100 yds and Im not
sure if it will cope with that distance. A!
> friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
>
>
>
>
>
Message 4
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| Subject: | Re: Aircraft Tug |
Thanks, Tom. Gotta add this one to my to do list.
Bill Bear
> On Apr 19, 2020, at 05:09, ktup122@aol.com wrote:
>
>
>
>
> ktup122@aol.com
>
>
> -----Original Message-----
> From: Tom Barter <kesleyelectric@iowatelecom.net>
> To: aeroelectric-list <aeroelectric-list@matronics.com>
> Sent: Sat, Apr 18, 2020 02:20 PM
> Subject: RE: AeroElectric-List: Aircraft Tug
>
>
> Attached is a photo of an aircraft tug a friend built from a walk behind snow
blower with a failed engine. The transmission allows speed control going forward
plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com>
On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject:
AeroElectric-List: Aircraft Tug Hello
all Im looking at building a 12v battery operated aircraft tug, not a ride on
just a walk with. My max aircraft weight will be about 1800 lbs. I am looking
for advise on what size motor I will need. There are a few 12v motors for sale
on ebay but they are not rated in hp so am not sure of what specs Im looking
at. One thought was to use a car starter motor but that is not rated for
continuous service but the farthest I will go with the tug is 100 yds and Im not
sure if it will cope with that distance. A!
> friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
>
>
>
>
>
Message 5
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| Subject: | Re: OV B-lead Relay |
Thanks for the explanation, Bob! Looks like it's the metal can or alternator surgery.
I'll do a little research on my alternator and the best surgery option.
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=495916#495916
Message 6
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| Subject: | Re: Aircraft Tug |
Thanks, Tom. Gotta add this one to my to do list.
Bill Bear
> On Apr 19, 2020, at 05:09, ktup122@aol.com wrote:
>
>
>
>
> ktup122@aol.com
>
>
> -----Original Message-----
> From: Tom Barter <kesleyelectric@iowatelecom.net>
> To: aeroelectric-list <aeroelectric-list@matronics.com>
> Sent: Sat, Apr 18, 2020 02:20 PM
> Subject: RE: AeroElectric-List: Aircraft Tug
>
>
> Attached is a photo of an aircraft tug a friend built from a walk behind snow
blower with a failed engine. The transmission allows speed control going forward
plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com>
On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject:
AeroElectric-List: Aircraft Tug Hello
all Im looking at building a 12v battery operated aircraft tug, not a ride on
just a walk with. My max aircraft weight will be about 1800 lbs. I am looking
for advise on what size motor I will need. There are a few 12v motors for sale
on ebay but they are not rated in hp so am not sure of what specs Im looking
at. One thought was to use a car starter motor but that is not rated for
continuous service but the farthest I will go with the tug is 100 yds and Im not
sure if it will cope with that distance. A!
> friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
>
>
>
>
>
Message 7
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| Subject: | Re: Aircraft Tug |
Thanks, Tom. Gotta add this one to my to do list.
Bill Bear
> On Apr 19, 2020, at 05:09, ktup122@aol.com wrote:
>
>
>
>
> ktup122@aol.com
>
>
> -----Original Message-----
> From: Tom Barter <kesleyelectric@iowatelecom.net>
> To: aeroelectric-list <aeroelectric-list@matronics.com>
> Sent: Sat, Apr 18, 2020 02:20 PM
> Subject: RE: AeroElectric-List: Aircraft Tug
>
>
> Attached is a photo of an aircraft tug a friend built from a walk behind snow
blower with a failed engine. The transmission allows speed control going forward
plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com>
On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject:
AeroElectric-List: Aircraft Tug Hello
all Im looking at building a 12v battery operated aircraft tug, not a ride on
just a walk with. My max aircraft weight will be about 1800 lbs. I am looking
for advise on what size motor I will need. There are a few 12v motors for sale
on ebay but they are not rated in hp so am not sure of what specs Im looking
at. One thought was to use a car starter motor but that is not rated for
continuous service but the farthest I will go with the tug is 100 yds and Im not
sure if it will cope with that distance. A!
> friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
>
>
>
>
>
Message 8
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| Subject: | Re: Aircraft Tug |
Thanks, Tom. Gotta add this one to my to do list.
Bill Bear
> On Apr 19, 2020, at 05:09, ktup122@aol.com wrote:
>
>
>
>
> ktup122@aol.com
>
>
> -----Original Message-----
> From: Tom Barter <kesleyelectric@iowatelecom.net>
> To: aeroelectric-list <aeroelectric-list@matronics.com>
> Sent: Sat, Apr 18, 2020 02:20 PM
> Subject: RE: AeroElectric-List: Aircraft Tug
>
>
> Attached is a photo of an aircraft tug a friend built from a walk behind snow
blower with a failed engine. The transmission allows speed control going forward
plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com>
On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject:
AeroElectric-List: Aircraft Tug Hello
all Im looking at building a 12v battery operated aircraft tug, not a ride on
just a walk with. My max aircraft weight will be about 1800 lbs. I am looking
for advise on what size motor I will need. There are a few 12v motors for sale
on ebay but they are not rated in hp so am not sure of what specs Im looking
at. One thought was to use a car starter motor but that is not rated for
continuous service but the farthest I will go with the tug is 100 yds and Im not
sure if it will cope with that distance. A!
> friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
>
>
>
>
>
Message 9
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| Subject: | Re: Aircraft Tug |
Thanks, Tom. Gotta add this one to my to do list.
Bill Bear
> On Apr 19, 2020, at 05:09, ktup122@aol.com wrote:
>
>
>
>
> ktup122@aol.com
>
>
> -----Original Message-----
> From: Tom Barter <kesleyelectric@iowatelecom.net>
> To: aeroelectric-list <aeroelectric-list@matronics.com>
> Sent: Sat, Apr 18, 2020 02:20 PM
> Subject: RE: AeroElectric-List: Aircraft Tug
>
>
> Attached is a photo of an aircraft tug a friend built from a walk behind snow
blower with a failed engine. The transmission allows speed control going forward
plus reverse. Works very well on his RV-6. Tom BarterFrom: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com>
On Behalf Of mike@vision499.comSent: Saturday, April 11, 2020 2:32 PMTo: aeroelectric-list@matronics.comSubject:
AeroElectric-List: Aircraft Tug Hello
all Im looking at building a 12v battery operated aircraft tug, not a ride on
just a walk with. My max aircraft weight will be about 1800 lbs. I am looking
for advise on what size motor I will need. There are a few 12v motors for sale
on ebay but they are not rated in hp so am not sure of what specs Im looking
at. One thought was to use a car starter motor but that is not rated for
continuous service but the farthest I will go with the tug is 100 yds and Im not
sure if it will cope with that distance. A!
> friend has also suggested converting an alternator into a motor, not sure what that entails. Ebay has scooter motors with a speed controller that seems ideal but not sure if that will be powerful enough but it will be geared right down. I look forward to hearing your thoughts and ideas Thanks Mike Virus-free. www.avast.com
>
>
>
>
>
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