Today's Message Index:
----------------------
1. 12:31 AM - Wrong email address - Re-send pls (Franz Fux)
2. 01:46 PM - Problem with starting (Alec Myers)
3. 01:58 PM - Re: Problem with starting (Kelly McMullen)
4. 02:19 PM - Re: Problem with starting (Alec Myers)
5. 02:33 PM - Re: Problem with starting (Justin Jones)
6. 02:36 PM - Re: Problem with starting (Justin Jones)
7. 02:53 PM - Re: Problem with starting ()
8. 03:07 PM - Re: Problem with starting (Alec Myers)
9. 03:53 PM - Re: Problem with starting (David Lloyd)
Message 1
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Subject: | Wrong email address - Re-send pls |
I will no longer be checking franz@lastfrontierheli.com due to excessive
and uncontrollable spam.
Please re-send your email to my new address:
franz.fux@lastfrontierheli.com and make a note of it for the future.
Apologies for the inconvenience,
Franz Fux
Last Frontier Heliskiing - Go Beyond
www.lastfrontierheli.com
---
Head Office: PO Box 1237, Vernon, BC V1T 6N6, CANADA
Tel: 250 558 7980
Fax: 250 558 7981
Reservations: 1-888-655-5566
Message 2
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Subject: | Problem with starting |
Fresh on the heels of asking for help with the low bus voltage with the engine
running in my C182, I now have an issue with intermittent cranking on start.
Symptoms:
About 5 times out of 10 turning the key switch to start elicits no prop movement.
Not even a tiny bit. The other times the cranking is healthy.
During a no-turn start, I can hear the starter contactor oscillate on/off at about
5Hz, the bus voltage drops to 6 volts or below, and after a few seconds the
earth braid from the battery to the fuselage gets warm/hot to touch.
Yesterday I had the alternator overhauled, and replaced: no change in behaviour.
Sometimes it cranks well 10 times in a row, sometimes it fails to turn, 10 times
in a row.
After a few trial starts today the battery was dead. So I gave it an external charge
20A for an hour. The next start failed. The one after that was fine, then
it went sulky and failed a few times.
Twice in maybe 40 trial starts (been working on this at various times over two
days now) the main (battery) contactor has remained shut and I have been unable
to shut off the power by turning off the master switch. The second time this
happened I gently tapped the battery contactor with a rubber tool and the contact
was successfully broken. I have now replaced this contactor. I imagine this
stuck-on behaviour is because the contact has tried to open due to low coil
voltage and welded itself shut because of an overcurrent condition.
Twice overall I have seen it enter this failure mode during cranking and while
the prop is turning: the prop stops and bounces back against the cylinder compression,
the bus voltage drops out and the contactor starts to buzz.
This is all consistent with a dead short either in, or downstream of the starter
contactor. I would be looking very hard at the starter motor, but I've already
had this overhauled, new springs, brushes etc., just yesterday.
Has anyone seen a failure like this in their experience? Anywhere else I could
look? It's really a very simple circuit and it must be drawing several hundred
amps somewhere...
Message 3
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Subject: | Re: Problem with starting |
Most likely your battery is on its last legs, or it has not achieved a
full charge. After being charged, and sitting overnight, the battery
resting voltage should be at least 12.7. If it is closer to 12.5, the
battery is either weak or didn't get fully charged. You could do, or
have done a capacity check.
On 6/17/2016 1:44 PM, Alec Myers wrote:
>
> Fresh on the heels of asking for help with the low bus voltage with the engine
running in my C182, I now have an issue with intermittent cranking on start.
>
> Symptoms:
>
> About 5 times out of 10 turning the key switch to start elicits no prop movement.
Not even a tiny bit. The other times the cranking is healthy.
>
> During a no-turn start, I can hear the starter contactor oscillate on/off at
about 5Hz, the bus voltage drops to 6 volts or below, and after a few seconds
the earth braid from the battery to the fuselage gets warm/hot to touch.
>
> Yesterday I had the alternator overhauled, and replaced: no change in behaviour.
Sometimes it cranks well 10 times in a row, sometimes it fails to turn, 10
times in a row.
>
> After a few trial starts today the battery was dead. So I gave it an external
charge 20A for an hour. The next start failed. The one after that was fine, then
it went sulky and failed a few times.
>
> Twice in maybe 40 trial starts (been working on this at various times over two
days now) the main (battery) contactor has remained shut and I have been unable
to shut off the power by turning off the master switch. The second time this
happened I gently tapped the battery contactor with a rubber tool and the contact
was successfully broken. I have now replaced this contactor. I imagine
this stuck-on behaviour is because the contact has tried to open due to low coil
voltage and welded itself shut because of an overcurrent condition.
>
> Twice overall I have seen it enter this failure mode during cranking and while
the prop is turning: the prop stops and bounces back against the cylinder compression,
the bus voltage drops out and the contactor starts to buzz.
>
> This is all consistent with a dead short either in, or downstream of the starter
contactor. I would be looking very hard at the starter motor, but I've already
had this overhauled, new springs, brushes etc., just yesterday.
>
> Has anyone seen a failure like this in their experience? Anywhere else I could
look? It's really a very simple circuit and it must be drawing several hundred
amps somewhere...
>
>
Message 4
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Subject: | Re: Problem with starting |
I did do a capacity check with a hand held device (basically it had a big heating
element in it) that runs for ten seconds and gives a go/no-go result - it said
the battery was "go".
The bit that confuses me about a failing battery being responsible is that on one
start the battery will produce enough current to pull the bus voltage down
to 6 volts and significantly heat the battery grounding strap (but in this scenario
not turn the prop), and on the very next try the bus voltage only drops
to 10 volts while the prop spins freely.
On 17Jun2016, at 4:56 PM, Kelly McMullen <kellym@aviating.com> wrote:
Most likely your battery is on its last legs, or it has not achieved a full charge.
After being charged, and sitting overnight, the battery resting voltage should
be at least 12.7. If it is closer to 12.5, the battery is either weak or
didn't get fully charged. You could do, or have done a capacity check.
On 6/17/2016 1:44 PM, Alec Myers wrote:
>
> Fresh on the heels of asking for help with the low bus voltage with the engine
running in my C182, I now have an issue with intermittent cranking on start.
>
> Symptoms:
>
> About 5 times out of 10 turning the key switch to start elicits no prop movement.
Not even a tiny bit. The other times the cranking is healthy.
>
> During a no-turn start, I can hear the starter contactor oscillate on/off at
about 5Hz, the bus voltage drops to 6 volts or below, and after a few seconds
the earth braid from the battery to the fuselage gets warm/hot to touch.
>
> Yesterday I had the alternator overhauled, and replaced: no change in behaviour.
Sometimes it cranks well 10 times in a row, sometimes it fails to turn, 10
times in a row.
>
> After a few trial starts today the battery was dead. So I gave it an external
charge 20A for an hour. The next start failed. The one after that was fine, then
it went sulky and failed a few times.
>
> Twice in maybe 40 trial starts (been working on this at various times over two
days now) the main (battery) contactor has remained shut and I have been unable
to shut off the power by turning off the master switch. The second time this
happened I gently tapped the battery contactor with a rubber tool and the contact
was successfully broken. I have now replaced this contactor. I imagine
this stuck-on behaviour is because the contact has tried to open due to low coil
voltage and welded itself shut because of an overcurrent condition.
>
> Twice overall I have seen it enter this failure mode during cranking and while
the prop is turning: the prop stops and bounces back against the cylinder compression,
the bus voltage drops out and the contactor starts to buzz.
>
> This is all consistent with a dead short either in, or downstream of the starter
contactor. I would be looking very hard at the starter motor, but I've already
had this overhauled, new springs, brushes etc., just yesterday.
>
> Has anyone seen a failure like this in their experience? Anywhere else I could
look? It's really a very simple circuit and it must be drawing several hundred
amps somewhere...
>
>
>
>
>
>
>
Message 5
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Subject: | Re: Problem with starting |
This sounds like an internal problem inside the starter or possibly a chaffing
wire (insulation rubbing thin or thru and grounding out) on the starter side on
the main contactor.
The problem with high current draws is that it can harm the components in the system.
The battery, wires, and both contactors can be destroyed.
Begin at the starter and trace the big wire all the way back to the battery looking
for any signs of chaffing or shorts. Do a continuity check between ground
and the main wire on the starter side of the contactors with the battery switch
off and battery disconnected from the airframe.
If you can't find an issue with the wire, try trying to disconnect the main wire
from the starter, insulate it (electricity isolating it) and attempt to crank
the starter as you would on a normal start (battery connected). If the battery
grounding braid gets hot, the starter isn't the issue and you have a short
to ground. If nothing happens, try a different starter.
Let us know.
Justin
> On Jun 17, 2016, at 16:56, Kelly McMullen <kellym@aviating.com> wrote:
>
>
> Most likely your battery is on its last legs, or it has not achieved a full charge.
After being charged, and sitting overnight, the battery resting voltage
should be at least 12.7. If it is closer to 12.5, the battery is either weak
or didn't get fully charged. You could do, or have done a capacity check.
>
>> On 6/17/2016 1:44 PM, Alec Myers wrote:
>>
>> Fresh on the heels of asking for help with the low bus voltage with the engine
running in my C182, I now have an issue with intermittent cranking on start.
>>
>> Symptoms:
>>
>> About 5 times out of 10 turning the key switch to start elicits no prop movement.
Not even a tiny bit. The other times the cranking is healthy.
>>
>> During a no-turn start, I can hear the starter contactor oscillate on/off at
about 5Hz, the bus voltage drops to 6 volts or below, and after a few seconds
the earth braid from the battery to the fuselage gets warm/hot to touch.
>>
>> Yesterday I had the alternator overhauled, and replaced: no change in behaviour.
Sometimes it cranks well 10 times in a row, sometimes it fails to turn, 10
times in a row.
>>
>> After a few trial starts today the battery was dead. So I gave it an external
charge 20A for an hour. The next start failed. The one after that was fine,
then it went sulky and failed a few times.
>>
>> Twice in maybe 40 trial starts (been working on this at various times over two
days now) the main (battery) contactor has remained shut and I have been unable
to shut off the power by turning off the master switch. The second time this
happened I gently tapped the battery contactor with a rubber tool and the
contact was successfully broken. I have now replaced this contactor. I imagine
this stuck-on behaviour is because the contact has tried to open due to low coil
voltage and welded itself shut because of an overcurrent condition.
>>
>> Twice overall I have seen it enter this failure mode during cranking and while
the prop is turning: the prop stops and bounces back against the cylinder compression,
the bus voltage drops out and the contactor starts to buzz.
>>
>> This is all consistent with a dead short either in, or downstream of the starter
contactor. I would be looking very hard at the starter motor, but I've already
had this overhauled, new springs, brushes etc., just yesterday.
>>
>> Has anyone seen a failure like this in their experience? Anywhere else I could
look? It's really a very simple circuit and it must be drawing several hundred
amps somewhere...
>
>
>
>
Message 6
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Subject: | Re: Problem with starting |
Alec, this is typical behavior of a short. See my last post to trouble shoot and
find the issue.
> On Jun 17, 2016, at 17:18, Alec Myers <alec@alecmyers.com> wrote:
>
>
> I did do a capacity check with a hand held device (basically it had a big heating
element in it) that runs for ten seconds and gives a go/no-go result - it
said the battery was "go".
>
> The bit that confuses me about a failing battery being responsible is that on
one start the battery will produce enough current to pull the bus voltage down
to 6 volts and significantly heat the battery grounding strap (but in this scenario
not turn the prop), and on the very next try the bus voltage only drops
to 10 volts while the prop spins freely.
>
>
>
>
> On 17Jun2016, at 4:56 PM, Kelly McMullen <kellym@aviating.com> wrote:
>
>
> Most likely your battery is on its last legs, or it has not achieved a full charge.
After being charged, and sitting overnight, the battery resting voltage
should be at least 12.7. If it is closer to 12.5, the battery is either weak
or didn't get fully charged. You could do, or have done a capacity check.
>
>> On 6/17/2016 1:44 PM, Alec Myers wrote:
>>
>> Fresh on the heels of asking for help with the low bus voltage with the engine
running in my C182, I now have an issue with intermittent cranking on start.
>>
>> Symptoms:
>>
>> About 5 times out of 10 turning the key switch to start elicits no prop movement.
Not even a tiny bit. The other times the cranking is healthy.
>>
>> During a no-turn start, I can hear the starter contactor oscillate on/off at
about 5Hz, the bus voltage drops to 6 volts or below, and after a few seconds
the earth braid from the battery to the fuselage gets warm/hot to touch.
>>
>> Yesterday I had the alternator overhauled, and replaced: no change in behaviour.
Sometimes it cranks well 10 times in a row, sometimes it fails to turn, 10
times in a row.
>>
>> After a few trial starts today the battery was dead. So I gave it an external
charge 20A for an hour. The next start failed. The one after that was fine,
then it went sulky and failed a few times.
>>
>> Twice in maybe 40 trial starts (been working on this at various times over two
days now) the main (battery) contactor has remained shut and I have been unable
to shut off the power by turning off the master switch. The second time this
happened I gently tapped the battery contactor with a rubber tool and the
contact was successfully broken. I have now replaced this contactor. I imagine
this stuck-on behaviour is because the contact has tried to open due to low coil
voltage and welded itself shut because of an overcurrent condition.
>>
>> Twice overall I have seen it enter this failure mode during cranking and while
the prop is turning: the prop stops and bounces back against the cylinder compression,
the bus voltage drops out and the contactor starts to buzz.
>>
>> This is all consistent with a dead short either in, or downstream of the starter
contactor. I would be looking very hard at the starter motor, but I've already
had this overhauled, new springs, brushes etc., just yesterday.
>>
>> Has anyone seen a failure like this in their experience? Anywhere else I could
look? It's really a very simple circuit and it must be drawing several hundred
amps somewhere...
>
>
>
>
>
>
>
>
>
>
Message 7
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Subject: | Re: Problem with starting |
---- Alec Myers <alec@alecmyers.com> wrote:
>
> I did do a capacity check with a hand held device (basically it had a big heating
element in it) that runs for ten seconds and gives a go/no-go result - it
said the battery was "go".
>
> The bit that confuses me about a failing battery being responsible is that on
one start the battery will produce enough current to pull the bus voltage down
to 6 volts and significantly heat the battery grounding strap (but in this scenario
not turn the prop), and on the very next try the bus voltage only drops
to 10 volts while the prop spins freely.
That the ground braid gets hot suggests a poor connection. I would disconnect the
braid and clean or replace and try again. jrh
Message 8
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Subject: | Re: Problem with starting |
The wire between the contactor and the starter is only six inches long no chafing
anywhere or even contact with anything else.
I can be confident there's no short upstream of the starter contactor because the
bus voltage dips out only when the starter contactor is energized.
I have disconnected the starter from its contactor and hit the start switch. The
contactor closes but there is no drop in bus voltage. As you would expect. The
only thing that makes me hesitate from blaming the starter motor 100% is that
the fault is intermittent so not seeing it on a few tests without the starter
in the circuit isn't entirely dispositive that the starter is the problem.
I could have just got lucky, and without the starter and engine turning there's
no vibration to shake things up.
Is it at all possible the contactor is intermittently shorting to the can? I am
going to try to find a DC clamp-on current meter. If while stalled there's about
200+ amps in the contactor-starter wire then the motor has to be the issue.
Unfortunately sourcing another starter just to try is infeasible.
On Jun 17, 2016, at 17:32, Justin Jones <jmjones2000@mindspring.com> wrote:
This sounds like an internal problem inside the starter or possibly a chaffing
wire (insulation rubbing thin or thru and grounding out) on the starter side on
the main contactor.
The problem with high current draws is that it can harm the components in the system.
The battery, wires, and both contactors can be destroyed.
Begin at the starter and trace the big wire all the way back to the battery looking
for any signs of chaffing or shorts. Do a continuity check between ground
and the main wire on the starter side of the contactors with the battery switch
off and battery disconnected from the airframe.
If you can't find an issue with the wire, try trying to disconnect the main wire
from the starter, insulate it (electricity isolating it) and attempt to crank
the starter as you would on a normal start (battery connected). If the battery
grounding braid gets hot, the starter isn't the issue and you have a short
to ground. If nothing happens, try a different starter.
Let us know.
Justin
> On Jun 17, 2016, at 16:56, Kelly McMullen <kellym@aviating.com> wrote:
>
>
> Most likely your battery is on its last legs, or it has not achieved a full charge.
After being charged, and sitting overnight, the battery resting voltage
should be at least 12.7. If it is closer to 12.5, the battery is either weak
or didn't get fully charged. You could do, or have done a capacity check.
>
>> On 6/17/2016 1:44 PM, Alec Myers wrote:
>>
>> Fresh on the heels of asking for help with the low bus voltage with the engine
running in my C182, I now have an issue with intermittent cranking on start.
>>
>> Symptoms:
>>
>> About 5 times out of 10 turning the key switch to start elicits no prop movement.
Not even a tiny bit. The other times the cranking is healthy.
>>
>> During a no-turn start, I can hear the starter contactor oscillate on/off at
about 5Hz, the bus voltage drops to 6 volts or below, and after a few seconds
the earth braid from the battery to the fuselage gets warm/hot to touch.
>>
>> Yesterday I had the alternator overhauled, and replaced: no change in behaviour.
Sometimes it cranks well 10 times in a row, sometimes it fails to turn, 10
times in a row.
>>
>> After a few trial starts today the battery was dead. So I gave it an external
charge 20A for an hour. The next start failed. The one after that was fine,
then it went sulky and failed a few times.
>>
>> Twice in maybe 40 trial starts (been working on this at various times over two
days now) the main (battery) contactor has remained shut and I have been unable
to shut off the power by turning off the master switch. The second time this
happened I gently tapped the battery contactor with a rubber tool and the
contact was successfully broken. I have now replaced this contactor. I imagine
this stuck-on behaviour is because the contact has tried to open due to low coil
voltage and welded itself shut because of an overcurrent condition.
>>
>> Twice overall I have seen it enter this failure mode during cranking and while
the prop is turning: the prop stops and bounces back against the cylinder compression,
the bus voltage drops out and the contactor starts to buzz.
>>
>> This is all consistent with a dead short either in, or downstream of the starter
contactor. I would be looking very hard at the starter motor, but I've already
had this overhauled, new springs, brushes etc., just yesterday.
>>
>> Has anyone seen a failure like this in their experience? Anywhere else I could
look? It's really a very simple circuit and it must be drawing several hundred
amps somewhere...
Message 9
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|
Subject: | Re: Problem with starting |
It is unusual but, a contactor can go bad.
Usually if it is mounted the wrong orientation and gets moisture inside
causing fungus or electrolysis corrosion on the contact surfaces that carry
the heavy current.
Since you state that the contactor and lead cable get warm/hot then, this
does not point to a failing ignition start switch usually. The starting
circuit to activate the contactor is fairly low current; about 5 amps or
less.
Another unusual failure is in the starter motor windings. The winding could
have a cracked armature heavy wire that makes or un-makes at random times.
Usually when heat is involved. I have seen this failure in alternators also.
Very difficult to chase down.. . .
------------------------------------------------------------------------------------
----- Original Message -----
From: "Alec Myers" <alec@alecmyers.com>
Sent: Friday, June 17, 2016 1:44 PM
Subject: AeroElectric-List: Problem with starting
>
> Fresh on the heels of asking for help with the low bus voltage with the
> engine running in my C182, I now have an issue with intermittent cranking
> on start.
>
> Symptoms:
>
> About 5 times out of 10 turning the key switch to start elicits no prop
> movement. Not even a tiny bit. The other times the cranking is healthy.
>
> During a no-turn start, I can hear the starter contactor oscillate on/off
> at about 5Hz, the bus voltage drops to 6 volts or below, and after a few
> seconds the earth braid from the battery to the fuselage gets warm/hot to
> touch.
>
> Yesterday I had the alternator overhauled, and replaced: no change in
> behaviour. Sometimes it cranks well 10 times in a row, sometimes it fails
> to turn, 10 times in a row.
>
> After a few trial starts today the battery was dead. So I gave it an
> external charge 20A for an hour. The next start failed. The one after that
> was fine, then it went sulky and failed a few times.
>
> Twice in maybe 40 trial starts (been working on this at various times over
> two days now) the main (battery) contactor has remained shut and I have
> been unable to shut off the power by turning off the master switch. The
> second time this happened I gently tapped the battery contactor with a
> rubber tool and the contact was successfully broken. I have now replaced
> this contactor. I imagine this stuck-on behaviour is because the contact
> has tried to open due to low coil voltage and welded itself shut because
> of an overcurrent condition.
>
> Twice overall I have seen it enter this failure mode during cranking and
> while the prop is turning: the prop stops and bounces back against the
> cylinder compression, the bus voltage drops out and the contactor starts
> to buzz.
>
> This is all consistent with a dead short either in, or downstream of the
> starter contactor. I would be looking very hard at the starter motor, but
> I've already had this overhauled, new springs, brushes etc., just
> yesterday.
>
> Has anyone seen a failure like this in their experience? Anywhere else I
> could look? It's really a very simple circuit and it must be drawing
> several hundred amps somewhere...
>
>
>
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