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alec(at)alecmyers.com
Guest

Posted: Fri Jun 17, 2016 12:46 pm Post 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...

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Fri Jun 17, 2016 12:58 pm Post subject: 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:

 	  Quote: 	
		   



 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...

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

alec(at)alecmyers.com
Guest

Posted: Fri Jun 17, 2016 1:19 pm Post subject: 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(at)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:

 	  Quote: 	
		   

 

 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...

jmjones2000(at)mindspring
Guest

Posted: Fri Jun 17, 2016 1:33 pm Post subject: 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

 	  Quote: 	
		   On Jun 17, 2016, at 16:56, Kelly McMullen <kellym(at)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...

jmjones2000(at)mindspring
Guest

Posted: Fri Jun 17, 2016 1:36 pm Post subject: Problem with starting

Alec, this is typical behavior of a short. See my last post to trouble shoot and find the issue. 



 	  Quote: 	
		   On Jun 17, 2016, at 17:18, Alec Myers <alec(at)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(at)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...

joerhenry(at)suddenlink.n
Guest

Posted: Fri Jun 17, 2016 1:53 pm Post subject: Problem with starting

---- Alec Myers <alec(at)alecmyers.com> wrote: 

 	  Quote: 	
		   

 

 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

alec(at)alecmyers.com
Guest

Posted: Fri Jun 17, 2016 2:07 pm Post subject: 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(at)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

 	  Quote: 	
		   On Jun 17, 2016, at 16:56, Kelly McMullen <kellym(at)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...

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Fri Jun 17, 2016 2:53 pm Post subject: 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.. . .



------------------------------------------------------------------------------------

---

ngeorge(at)continentalmot
Guest

Posted: Sat Jun 18, 2016 5:53 am Post subject: Problem with starting

Alec - 

Which starter motor is on your engine?

If it is an ISKRA, you should take it out of service.  Replace the starter adapter while you're at it - it is probably damages as well.  ISKRA starters feature a planetary gear train that is subject to magnetization and binding. Catastrophic engine failure from starter adapter failure is a real possibility.  



I have a starter motor I'll let you borrow...



Neal

Continental Motors Tech Support



===========

Unfortunately sourcing another starter just to try is infeasible.

alec(at)alecmyers.com
Guest

Posted: Sat Jun 18, 2016 6:46 am Post subject: Problem with starting

Hi Neal



Tha



 	  Quote: 	
		   On Jun 18, 2016, at 9:51 AM, Neal George <ngeorge(at)continentalmotors.aero> wrote:

 

 

 

 Alec - 

 Which starter motor is on your engine?

 If it is an ISKRA, you should take it out of service.  Replace the starter adapter while you're at it - it is probably damages as well.  ISKRA starters feature a planetary gear train that is subject to magnetization and binding. Catastrophic engine failure from starter adapter failure is a real possibility.  

 

 I have a starter motor I'll let you borrow...

 

 Neal

 Continental Motors Tech Support

 

 ===========

 Unfortunately sourcing another starter just to try is infeasible.

alec(at)alecmyers.com
Guest

Posted: Sat Jun 18, 2016 6:51 am Post subject: Problem with starting

Hi Neal



That's very kind! The motor is an original Continental heavy one - direct drive. No evidence of slipping in the adapter. Changing the adapter involves partially removing the engine to gain clearance which I'd like to avoid if possible. Can you get me a stater to borrow to Canada where I am?



 	  Quote: 	
		   On Jun 18, 2016, at 10:45 AM, Alec Myers <alec(at)alecmyers.com> wrote:

 

 Hi Neal

 

 Tha

 

> On Jun 18, 2016, at 9:51 AM, Neal George <ngeorge(at)continentalmotors.aero> wrote:

> 

> 

> 

> Alec - 

> Which starter motor is on your engine?

> If it is an ISKRA, you should take it out of service.  Replace the starter adapter while you're at it - it is probably damages as well.  ISKRA starters feature a planetary gear train that is subject to magnetization and binding. Catastrophic engine failure from starter adapter failure is a real possibility.  

> 

> I have a starter motor I'll let you borrow...

> 

> Neal

> Continental Motors Tech Support

> 

> ===========

> Unfortunately sourcing another starter just to try is infeasible.

> 

> 

> 

> 

> 

>

ngeorge(at)continentalmot
Guest

Posted: Sat Jun 18, 2016 11:11 am Post subject: Problem with starting

Canada and the cost/aggravation of Customs makes it tough.  



If you have a Hartzell Energizer, the probability of the starter motor being the problem is low unless it has been badly abused.  Pull the motor and take it to your local automotive alternator & starter repair shop - they ought to be able to test it.  



Neal



--

skywagon

Joined: 11 Feb 2006
Posts: 184

Posted: Sat Jun 18, 2016 1:14 pm Post subject: Problem with starting

. . .  never tell an "auto" shop that a part is off an aircraft. . .!



Tell them it is off a boat, tractor, etc. !!



Most shops in US have a built alarm system that they cannot "touch" anything 

off of an aircraft, even to test it. . .

Maybe the same in Canada. . . .

Dave



_____________________________________________________________________-



---

alec(at)alecmyers.com
Guest

Posted: Sat Jun 18, 2016 1:25 pm Post subject: Problem with starting

It's an Energiser 12, with a TCM label.



Is it possible that an intermittent open-circuit in the armature could cause this? If the rotor goes open circuit the motor stops, the back EMF disappears and the current rises, just like if the motor was stalled. That would draw a lot of current, right?



I had the motor overhauled already this last week, after first seeing the problem. Perhaps they missed the fault, but when I take it back it would be good to know what to suggest, especially if looking for something intermittent.



On Jun 18, 2016, at 15:09, Neal George <ngeorge(at)continentalmotors.aero> wrote:






Canada and the cost/aggravation of Customs makes it tough.  



If you have a Hartzell Energizer, the probability of the starter motor being the problem is low unless it has been badly abused.  Pull the motor and take it to your local automotive alternator & starter repair shop - they ought to be able to test it.  



Neal



--

stephencliverichards(at)g
Guest

Posted: Sun Jun 19, 2016 12:02 am Post subject: Problem with starting

These are series motors so it will have to be a short circuit could be a intermittent short of field is a live brush tail grounding ? Alternatively is it mechanically seizing.

Clive 



From: Alec Myers (alec(at)alecmyers.com)

Sent: ‎18/‎06/‎2016 22:30

To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)

Subject: Re: AeroElectric-List: Problem with starting

--> AeroElectric-List message posted by: Alec Myers <alec(at)alecmyers.com>



It's an Energiser 12, with a TCM label.



Is it possible that an intermittent open-circuit in the armature could cause this? If the rotor goes open circuit the motor stops, the back EMF disappears and the current rises, just like if the motor was stalled. That would draw a lot of current, right?



I had the motor overhauled already this last week, after first seeing the problem. Perhaps they missed the fault, but when I take it back it would be good to know what to suggest, especially if looking for something intermittent.



On Jun 18, 2016, at 15:09, Neal George <ngeorge(at)continentalmotors.aero> wrote:



--> AeroElectric-List message posted by: Neal George <ngeorge(at)continentalmotors.aero>



Canada and the cost/aggravation of Customs makes it tough.  



If you have a Hartzell Energizer, the probability of the starter motor being the problem is low unless it has been badly abused.  Pull the motor and take it to your local automotive alternator & starter repair shop - they ought to be able to test it.  



Neal



--

alec(at)alecmyers.com
Guest

Posted: Sun Jun 19, 2016 4:41 am Post subject: Problem with starting

Neal 



I see from the TCM service manual that faults in the windings of the Energizer motor are not repairable. SIL02-04 says the TCM replacement is now the Iskra starter that you don't recommend.



Given that I have the old-style starter adapter If I need a new motor which would you recommend?



[quote] On Jun 18, 2016, at 3:09 PM, Neal George <ngeorge(at)continentalmotors.aero> wrote:

 

 

 

 Canada and the cost/aggravation of Customs makes it tough.  

 

 If you have a Hartzell Energizer, the probability of the starter motor being the problem is low unless it has been badly abused.  Pull the motor and take it to your local automotive alternator & starter repair shop - they ought to be able to test it.  

 

 Neal

 

 --

ngeorge(at)continentalmot
Guest

Posted: Sun Jun 19, 2016 5:01 am Post subject: Problem with starting

Did I misunderstand that you just had the motor overhauled?



All Continental starter adapters have the same motor interface.



The current starter adapter for Sandcast engines is indeed different and is not interchangeable with the older version.  If you have the old-style adapter, if it fails you will need to have it overhauled.  Your engine can be modified to accept the new adapter, but requires splitting the crankcase.  



The Energizer starter motor from Hartzell Engine Technologies is the preferred unit.



I'm still not convinced you have a motor problem.  The chattering relay points more to circuit / system and low voltage issues.  



neal



--

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jun 19, 2016 5:30 am Post subject: Problem with starting

 	  Quote: 	
		  

 I'm still not convinced you have a motor problem.  The chattering relay points more to circuit / system and low voltage issues.  



 neal 	


   Except that a contactor powered from the same

   battery that is being pulled down by what amounts

   to continuous stall current may well drop-out

   during closures only to re-close when the contacts

   break and stall-current goes away.



   12v battery contactors drop at about 2v . . . and

   are not likely to be candidates for 'buzzing' but

   it's not impossible. A easy experiment would call

   for powering the starter contactor from a separate

   source . . . like another battery. It may well

   stop chattering. But the energies being circulated

   will be profound.



   I'm puzzled by the intermittent nature of the

   symptom. This implies a root cause that

   is transient or loose to rattle around. Having

   the starter motor come to rest on a bad pass

   in the armature windings could account for such

   behavior.



   It would sure be illuminating to put a data acquisition

   system on it to capture all the voltages/currents

   during the event.



 

   Bob . . .

alec(at)alecmyers.com
Guest

Posted: Sun Jun 19, 2016 5:45 am Post subject: Problem with starting

The strangest symptom is that twice the motor has cut out (and the bus voltage was pulled down) mid-crank while the prop was already turning at a good starting speed. I think that suggests it's not a bad spot on the commutator, for example.

I can rule out mechanical seizure at the crank because when the motor cut, the prop immediately bounced back off a compression stroke, and (I think) I can rule out a starter jam because the engine has started and run since.

I thought I was onto something with a possible fracture in the field winding but that won't explain things if the motor isn't shunt wound.



On Jun 19, 2016, at 09:29, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

   	  Quote: 	
		  

 I'm still not convinced you have a motor problem.  The chattering relay points more to circuit / system and low voltage issues.  



 neal 	


   Except that a contactor powered from the same

   battery that is being pulled down by what amounts

   to continuous stall current may well drop-out

   during closures only to re-close when the contacts

   break and stall-current goes away.



   12v battery contactors drop at about 2v . . . and

   are not likely to be candidates for 'buzzing' but

   it's not impossible. A easy experiment would call

   for powering the starter contactor from a separate

   source . . . like another battery. It may well

   stop chattering. But the energies being circulated

   will be profound.



   I'm puzzled by the intermittent nature of the

   symptom. This implies a root cause that

   is transient or loose to rattle around. Having

   the starter motor come to rest on a bad pass

   in the armature windings could account for such

   behavior.



   It would sure be illuminating to put a data acquisition

   system on it to capture all the voltages/currents

   during the event.



 

   Bob . . .

ngeorge(at)continentalmot
Guest

Posted: Sun Jun 19, 2016 6:01 am Post subject: Problem with starting

I considered that, thought it unlikely since the motor was recently serviced.   

I had a similar failure on my 99 Suburban.   

Turn the key; nothing.   

Smack the starter with a mallet, it would come to life… 

  

neal 

  

  I'm puzzled by the intermittent nature of the

   symptom. This implies a root cause that

   is transient or loose to rattle around. Having

   the starter motor come to rest on a bad pass

   in the armature windings could account for such

   behavior. <![if !supportLineBreakNewLine]> <![endif]> 

  Bob . . .

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