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user9253
Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan
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 Posted: Wed Apr 04, 2018 7:55 am Post subject: Starter SURGES |
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The following was posted today on Vansairforce. Are the statements below true?
| Quote: | | "Starters that use a permanent magnet instead of a wound field most certainly can and will cause voltage surges that will take out avionics. The EXP2 will not filter out surges. Strongly recommend you rewire the EXP2 to have the Avionics shut down on cranking or better yet don't turn the avionics on until engine is started and running. Voltage spikes are of a quick transient nature and can exceed several hundred volts. They can be fast enough that the clamping diode will not completely shunt the spike." |
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alec(at)alecmyers.com
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| Posted: Wed Apr 04, 2018 11:01 am Post subject: Starter SURGES |
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I don’t know about the first bit but I’m very dubious about “They can be fast enough that the clamping diode will not completely shunt the spike”.
I don’t think it takes more than a few nanoseconds for a junction diode to go into conduction; they rectify very high frequency signals, after all. And the junction looks like a small capacitance which at a high enough frequency will “short” a signal even without conducting.
On Apr 4, 2018, at 11:55, user9253 <fransew(at)gmail.com> wrote:
The following was posted today on Vansairforce. Are the statements below true?
| Quote: | "Starters that use a permanent magnet instead of a wound field most certainly can and will cause voltage surges that will take out avionics. The EXP2 will not filter out surges. Strongly recommend you rewire the EXP2 to have the Avionics shut down on cranking or better yet don't turn the avionics on until engine is started and running. Voltage spikes are of a quick transient nature and can exceed several hundred volts. They can be fast enough that the clamping diode will not completely shunt the spike."
|
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=479039#479039
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echristley(at)att.net
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| Posted: Wed Apr 04, 2018 12:47 pm Post subject: Starter SURGES |
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If the bendix gear is sticky, such that the engine is able to drive the starter, I could imagine that it could push a fairly high (albeit short) number of joules back up the wire. Right?
On Wednesday, April 4, 2018 3:03 PM, Alec Myers <alec(at)alecmyers.com> wrote:
--> AeroElectric-List message posted by: Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)>
I don’t know about the first bit but I’m very dubious about “They can be fast enough that the clamping diode will not completely shunt the spike”.
I don’t think it takes more than a few nanoseconds for a junction diode to go into conduction; they rectify very high frequency signals, after all. And the junction looks like a small capacitance which at a high enough frequency will “short” a signal even without conducting.
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nuckolls.bob(at)aeroelect
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| Posted: Wed Apr 04, 2018 12:50 pm Post subject: Starter SURGES |
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At 10:55 AM 4/4/2018, you wrote:
| Quote: | --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>
The following was posted today on Vansairforce. Are the statements below true?
> "Starters that use a permanent magnet instead of a wound field most certainly can and will cause voltage surges that will take out avionics. The EXP2 will not filter out surges. Strongly recommend you rewire the EXP2 to have the Avionics shut down on cranking or better yet don't turn the avionics on until engine is started and running. Voltage spikes are of a quick transient nature and can exceed several hundred volts. They can be fast enough that the clamping diode will not completely shunt the spike." |
Some ol' hangar tales just never die. 99.9% of the
legacy 'spikes' narratives are simply unfounded in
physics and not demonstrated in practice.
I spent 45+ years chasing gremlins, goblins and
poltergeists in aircraft DC power systems. Not
once was the root event of a problem attributable to
an UNEXPECTED transient condition on the bus.
UNEXPECTED is the operative word here . . .
DO160/M-Std-704 are teamed up to define what
hazards are EXPECTED and what firewalls are
recommended for meeting those expectations.
We've been successfully building and operating
all manner of electronic and electrical accessory
under these guidelines for about 80 years.
The narrative cited above is pretty strange . . .
"fast enough that the clamping diode will not
completely shunt the spike". Really? Such
assertions should be able to cite supporting
documentation where a test setup was fabricated,
tests conducted, measurements taken and deductions
made.
Graybeards on the List may recall numerous discussions
wherein I went to the bench, did the setup, recorded
the results and published the deductions.
The 'cranking spike' thingy doesn't exist. What
ever bus voltage perturbations exist are NORMAL,
EXPECTED and well addressed by rudimentary and
now cookie-cutter design philosophies nearly
a century old.
I'd be pleased to send $100 to any individual
who can document any conditions to the contrary
and publish them here on the List.
Bob . . .
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Wed Apr 04, 2018 1:38 pm Post subject: Starter SURGES |
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At 03:46 PM 4/4/2018, you wrote:
| Quote: | | If the bendix gear is sticky, such that the engine is able to drive the starter, I could imagine that it could push a fairly high (albeit short) number of joules back up the wire. Right? |
the 'Bendix' drive is gone. All starters
use direct engagement solenoids.
A return spring retracts the pinion
gear upon removal of power from the
motor. In fact, electrical power to
the motor is interrupted during the initial
retraction so there is no torque being
transmitted from motor to ring gear.
At the same time, an overrun clutch
https://tinyurl.com/y7prvn7b
prevents the accelerating engine
from back-driving the starter. If
this clutch were not present, first
motion of the engine during pinion gear
retraction would break things.
This feature was built into the legacy
'bendix' drive. Starter motor acceleration
working against pinion gear mass would
drive it outward on the shaft by means
of a spiral groove on the shaft . . .
engine acceleration tending to over-run
the starter would drive the pinion back
from the ring gear with the same groove.
[img]cid:.0[/img]
There have been some hangar-tales of starter
pinions 'sticking' and back driving starters.
There have been cases of contactor sticking
keeping power on the starter thus maintaining
pinion engagement. But no back driving could
have occurred due to action of the clutch.
Had the motor been driven backwards at the
pinion to ring gear ratio, it would probably
have slung wires out of the armature and/or
stripped gear teeth.
The same gear reduction of pinion-to-ring
allows starter armature to run at several
thousand rpm to generated 200 rpm at the
crankshaft. Okay, after engine start and
run at 1000 rpm, a back-driving situation would
spin the starter armature 10000 rpm plus?
Bob . . .
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Wed Apr 04, 2018 4:50 pm Post subject: Starter SURGES |
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Bob, all, When I graduated high school back in the dark ages I had a 1959 Alfa Romeo Giullietta Spider that had a nightmare starter system. First, the electrical system was positive ground. That alone made things interesting but the starter, or rather the starter switch was the flash point of failure. Why? Because it had no spring return. You had to physically turn the starter motor off or the starter would stay connected with the ring gear and the engine would drive the starter. I was warned by the guy who sold me the car and I only left it engaged once for a few seconds. The grinding sound was kind of a give away and I got away with it. When I sold the car to my best friend I told him what I'd been told, "Never, ever let anyone else drive this car". About four weeks after Dave bought it, he let his step brother drive the car. He left the starter engaged for the entire 10 miles he drove it. The next day, the battery was dead. When checked, it had internal shorts and was junk. Dave bought a new Die Hard, the new thing in battery advertising, if not battery technology. It lasted a couple of weeks and Dave took it back to Sears. The battery was tested and failed. He got a new one. It too failed in short order. This went on for FOUR batteries before the manager at the Arden Way Sears gave my friend a full refund and refused to sell him any more batteries. Somewhere in the mess the starter failed and was replaced, the generator failed, the headlights would burn out on a regular basis and my friend almost became my ex-friend. He was a poor college student trying to fix the car with suggestions from his dad and some mechanics he knew. Finally his folks loaned him the money to take it to a garage that worked on Alfas and they determined that the voltage regulator was fried, too. This had gone on for almost six months before he finally had the car back in a dependable condition.So my take is, yeah, drive the starter and turn it into a generator and things are going to screw up in a major way.
Rick Girard
PS Probably the worst part came when Dave was finally able to enjoy the car again he took it for a drive on a beautiful day. A truck in front of him kicked up a stone that went right through the radiator. He pulled into a service station and the engine rattled to a stop. The kid at the pump popped open the hood and started filling the radiator before Dave could stop him. Put a crack all the way across the roof of the number three combustion chamber.
On Wed, Apr 4, 2018 at 4:37 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 03:46 PM 4/4/2018, you wrote:
| Quote: | | If the bendix gear is sticky, such that the engine is able to drive the starter, I could imagine that it could push a fairly high (albeit short) number of joules back up the wire. Right? |
the 'Bendix' drive is gone. All starters
use direct engagement solenoids.
A return spring retracts the pinion
gear upon removal of power from the
motor. In fact, electrical power to
the motor is interrupted during the initial
retraction so there is no torque being
transmitted from motor to ring gear.
At the same time, an overrun clutch
https://tinyurl.com/y7prvn7b
prevents the accelerating engine
from back-driving the starter. If
this clutch were not present, first
motion of the engine during pinion gear
retraction would break things.
This feature was built into the legacy
'bendix' drive. Starter motor acceleration
working against pinion gear mass would
drive it outward on the shaft by means
of a spiral groove on the shaft . . .
engine acceleration tending to over-run
the starter would drive the pinion back
from the ring gear with the same groove.
[img]cid:.0[/img]
There have been some hangar-tales of starter
pinions 'sticking' and back driving starters.
There have been cases of contactor sticking
keeping power on the starter thus maintaining
pinion engagement. But no back driving could
have occurred due to action of the clutch.
Had the motor been driven backwards at the
pinion to ring gear ratio, it would probably
have slung wires out of the armature and/or
stripped gear teeth.
The same gear reduction of pinion-to-ring
allows starter armature to run at several
thousand rpm to generated 200 rpm at the
crankshaft. Okay, after engine start and
run at 1000 rpm, a back-driving situation would
spin the starter armature 10000 rpm plus?
Bob . . .
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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133.77 KB |
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8795 Time(s) |
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_________________
The smallest miracle right in front of you is enough to make you happy.... |
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ceengland7(at)gmail.com
Guest
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| Posted: Wed Apr 04, 2018 5:15 pm Post subject: Starter SURGES |
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|
At 1st glance, I'd suspect there's a flaw in the analysis. If the switch wasn't releasing, then the starter was still powered, regardless of whether the engine could drive it or not. That would mean it was running the entire time the car was running, and starters are not designed for that. Given the obvious lack of knowledge about the car and limited expertise of the people working on it, with that many service operations by those people working on it I'd find it difficult to pick any likely failure mode for the stuff that failed. Just one thought about the failure of the regulator: uninformed installation of the battery, even once.
FWIW,
Charlie
On 4/4/2018 7:49 PM, Richard Girard wrote:
| Quote: | Bob, all, When I graduated high school back in the dark ages I had a 1959 Alfa Romeo Giullietta Spider that had a nightmare starter system. First, the electrical system was positive ground. That alone made things interesting but the starter, or rather the starter switch was the flash point of failure. Why? Because it had no spring return. You had to physically turn the starter motor off or the starter would stay connected with the ring gear and the engine would drive the starter. I was warned by the guy who sold me the car and I only left it engaged once for a few seconds. The grinding sound was kind of a give away and I got away with it. When I sold the car to my best friend I told him what I'd been told, "Never, ever let anyone else drive this car". About four weeks after Dave bought it, he let his step brother drive the car. He left the starter engaged for the entire 10 miles he drove it. The next day, the battery was dead. When checked, it had internal shorts and was junk. Dave bought a new Die Hard, the new thing in battery advertising, if not battery technology. It lasted a couple of weeks and Dave took it back to Sears. The battery was tested and failed. He got a new one. It too failed in short order. This went on for FOUR batteries before the manager at the Arden Way Sears gave my friend a full refund and refused to sell him any more batteries. Somewhere in the mess the starter failed and was replaced, the generator failed, the headlights would burn out on a regular basis and my friend almost became my ex-friend. He was a poor college student trying to fix the car with suggestions from his dad and some mechanics he knew. Finally his folks loaned him the money to take it to a garage that worked on Alfas and they determined that the voltage regulator was fried, too. This had gone on for almost six months before he finally had the car back in a dependable condition. So my take is, yeah, drive the starter and turn it into a generator and things are going to screw up in a major way.
Rick Girard
PS Probably the worst part came when Dave was finally able to enjoy the car again he took it for a drive on a beautiful day. A truck in front of him kicked up a stone that went right through the radiator. He pulled into a service station and the engine rattled to a stop. The kid at the pump popped open the hood and started filling the radiator before Dave could stop him. Put a crack all the way across the roof of the number three combustion chamber.
On Wed, Apr 4, 2018 at 4:37 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 03:46 PM 4/4/2018, you wrote:
| Quote: | | If the bendix gear is sticky, such that the engine is able to drive the starter, I could imagine that it could push a fairly high (albeit short) number of joules back up the wire. Right? |
the 'Bendix' drive is gone. All starters
use direct engagement solenoids.
A return spring retracts the pinion
gear upon removal of power from the
motor. In fact, electrical power to
the motor is interrupted during the initial
retraction so there is no torque being
transmitted from motor to ring gear.
At the same time, an overrun clutch
https://tinyurl.com/y7prvn7b
prevents the accelerating engine
from back-driving the starter. If
this clutch were not present, first
motion of the engine during pinion gear
retraction would break things.
This feature was built into the legacy
'bendix' drive. Starter motor acceleration
working against pinion gear mass would
drive it outward on the shaft by means
of a spiral groove on the shaft . . .
engine acceleration tending to over-run
the starter would drive the pinion back
from the ring gear with the same groove.
[img]cid:part4.A59D0A75.D6F8A8FE(at)gmail.com[/img]
There have been some hangar-tales of starter
pinions 'sticking' and back driving starters.
There have been cases of contactor sticking
keeping power on the starter thus maintaining
pinion engagement. But no back driving could
have occurred due to action of the clutch.
Had the motor been driven backwards at the
pinion to ring gear ratio, it would probably
have slung wires out of the armature and/or
stripped gear teeth.
The same gear reduction of pinion-to-ring
allows starter armature to run at several
thousand rpm to generated 200 rpm at the
crankshaft. Okay, after engine start and
run at 1000 rpm, a back-driving situation would
spin the starter armature 10000 rpm plus?
Bob . . .
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Wed Apr 04, 2018 6:11 pm Post subject: Starter SURGES |
|
|
Charlie, You're right, the starter was engaged and running but the minute
the engine revved over starting rpm the engine was driving it, too. It's
probably no surprise that the car had English electrics, a mix of Smith and
Lucas. Me experience with it was too many ghost problems. The horn began to
blow one night right as I was on my way out for a date. Disconnected the
horn, went on the date and tried to get the horn working the next day.
Reconnected it and nothing wrong. Never failed again. Then there was the
night the passing lights started flashing on their own. Pulled the whole
steering wheel off, went through it, couldn't find anything, put it back
together, worked fine. Never failed again. As much as I loved the car I
began to think of it as Mussolini's revenge. I didn't know about Lucas
then.....
Rick
On Wed, Apr 4, 2018 at 8:14 PM, Charlie England <ceengland7(at)gmail.com>
wrote:
[quote] At 1st glance, I'd suspect there's a flaw in the analysis. If the switch
wasn't releasing, then the starter was still powered, regardless of whether
the engine could drive it or not. That would mean it was running the entire
time the car was running, and starters are not designed for that. Given the
obvious lack of knowledge about the car and limited expertise of the people
working on it, with that many service operations by those people working on
it I'd find it difficult to pick any likely failure mode for the stuff that
failed. Just one thought about the failure of the regulator: uninformed
installation of the battery, even once.
FWIW,
Charlie
On 4/4/2018 7:49 PM, Richard Girard wrote:
Bob, all, When I graduated high school back in the dark ages I had a 1959
Alfa Romeo Giullietta Spider that had a nightmare starter system. First,
the electrical system was positive ground. That alone made things
interesting but the starter, or rather the starter switch was the flash
point of failure. Why? Because it had no spring return. You had to
physically turn the starter motor off or the starter would stay connected
with the ring gear and the engine would drive the starter. I was warned by
the guy who sold me the car and I only left it engaged once for a few
seconds. The grinding sound was kind of a give away and I got away with it.
When I sold the car to my best friend I told him what I'd been told,
"Never, ever let anyone else drive this car". About four weeks after Dave
bought it, he let his step brother drive the car. He left the starter
engaged for the entire 10 miles he drove it. The next day, the battery was
dead. When checked, it had internal shorts and was junk. Dave bought a new
Die Hard, the new thing in battery advertising, if not battery technology
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
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_________________
The smallest miracle right in front of you is enough to make you happy.... |
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ceengland7(at)gmail.com
Guest
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| Posted: Wed Apr 04, 2018 6:47 pm Post subject: Starter SURGES |
|
|
Oh, Lucus. You buried the lead. And explained all the problems in one word.
Just so you know, it didn't get much better in the intervening 11 years; the '70 Spyder I owned housed a demon who made sure I never knew when it would start. Always turned over, but the bizarre and primitive electro-mechanical injection had a mind (or demon) of its own.
On 4/4/2018 9:11 PM, Richard Girard wrote:
| Quote: | Charlie, You're right, the starter was engaged and running but the minute the engine revved over starting rpm the engine was driving it, too. It's probably no surprise that the car had English electrics, a mix of Smith and Lucas. Me experience with it was too many ghost problems. The horn began to blow one night right as I was on my way out for a date. Disconnected the horn, went on the date and tried to get the horn working the next day. Reconnected it and nothing wrong. Never failed again. Then there was the night the passing lights started flashing on their own. Pulled the whole steering wheel off, went through it, couldn't find anything, put it back together, worked fine. Never failed again. As much as I loved the car I began to think of it as Mussolini's revenge. I didn't know about Lucas then.....
Rick
On Wed, Apr 4, 2018 at 8:14 PM, Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
| Quote: | At 1st glance, I'd suspect there's a flaw in the analysis. If the switch wasn't releasing, then the starter was still powered, regardless of whether the engine could drive it or not. That would mean it was running the entire time the car was running, and starters are not designed for that. Given the obvious lack of knowledge about the car and limited expertise of the people working on it, with that many service operations by those people working on it I'd find it difficult to pick any likely failure mode for the stuff that failed. Just one thought about the failure of the regulator: uninformed installation of the battery, even once.
FWIW,
Charlie
On 4/4/2018 7:49 PM, Richard Girard wrote:
| Quote: | Bob, all, When I graduated high school back in the dark ages I had a 1959 Alfa Romeo Giullietta Spider that had a nightmare starter system. First, the electrical system was positive ground. That alone made things interesting but the starter, or rather the starter switch was the flash point of failure. Why? Because it had no spring return. You had to physically turn the starter motor off or the starter would stay connected with the ring gear and the engine would drive the starter. I was warned by the guy who sold me the car and I only left it engaged once for a few seconds. The grinding sound was kind of a give away and I got away with it. When I sold the car to my best friend I told him what I'd been told, "Never, ever let anyone else drive this car". About four weeks after Dave bought it, he let his step brother drive the car. He left the starter engaged for the entire 10 miles he drove it. The next day, the battery was dead. When checked, it had internal shorts and was junk. Dave bought a new Die Hard, the new thing in battery advertising, if not battery technology. It lasted a couple of weeks and Dave took it back to Sears. The battery was tested and failed. He got a new one. It too failed in short order. This went on for FOUR batteries before the manager at the Arden Way Sears gave my friend a full refund and refused to sell him any more batteries. Somewhere in the mess the starter failed and was replaced, the generator failed, the headlights would burn out on a regular basis and my friend almost became my ex-friend. He was a poor college student trying to fix the car with suggestions from his dad and some mechanics he knew. Finally his folks loaned him the money to take it to a garage that worked on Alfas and they determined that the voltage regulator was fried, too. This had gone on for almost six months before he finally had the car back in a dependable condition. So my take is, yeah, drive the starter and turn it into a generator and things are going to screw up in a major way.
Rick Girard
PS Probably the worst part came when Dave was finally able to enjoy the car again he took it for a drive on a beautiful day. A truck in front of him kicked up a stone that went right through the radiator. He pulled into a service station and the engine rattled to a stop. The kid at the pump popped open the hood and started filling the radiator before Dave could stop him. Put a crack all the way across the roof of the number three combustion chamber.
On Wed, Apr 4, 2018 at 4:37 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 03:46 PM 4/4/2018, you wrote:
| Quote: | | If the bendix gear is sticky, such that the engine is able to drive the starter, I could imagine that it could push a fairly high (albeit short) number of joules back up the wire. Right? |
the 'Bendix' drive is gone. All starters
use direct engagement solenoids.
A return spring retracts the pinion
gear upon removal of power from the
motor. In fact, electrical power to
the motor is interrupted during the initial
retraction so there is no torque being
transmitted from motor to ring gear.
At the same time, an overrun clutch
https://tinyurl.com/y7prvn7b
prevents the accelerating engine
from back-driving the starter. If
this clutch were not present, first
motion of the engine during pinion gear
retraction would break things.
This feature was built into the legacy
'bendix' drive. Starter motor acceleration
working against pinion gear mass would
drive it outward on the shaft by means
of a spiral groove on the shaft . . .
engine acceleration tending to over-run
the starter would drive the pinion back
from the ring gear with the same groove.
[img]cid:part5.C7D05308.20472A9D(at)gmail.com[/img]
There have been some hangar-tales of starter
pinions 'sticking' and back driving starters.
There have been cases of contactor sticking
keeping power on the starter thus maintaining
pinion engagement. But no back driving could
have occurred due to action of the clutch.
Had the motor been driven backwards at the
pinion to ring gear ratio, it would probably
have slung wires out of the armature and/or
stripped gear teeth.
The same gear reduction of pinion-to-ring
allows starter armature to run at several
thousand rpm to generated 200 rpm at the
crankshaft. Okay, after engine start and
run at 1000 rpm, a back-driving situation would
spin the starter armature 10000 rpm plus?
Bob . . .
|
--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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rickofudall
Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA
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| Posted: Wed Apr 04, 2018 8:20 pm Post subject: Starter SURGES |
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Good to know I'm not the only one. Mine wouldn't start one day and I started going through the manual. Check the condenser with this method it said. Bad condenser. The guy at the NAPA store told me, "condensers never go bad, you need a coil". No, I need a condenser. HA HA HA, kid doesn't know anything about cars, does he. They all got a big laugh out of. Finally got them to sell me a damn condenser. Put it in, started right up, took the bad condenser back to NAPA and dared the guy to put it in his car. It wasn't until I was on my way home that it occurred to me, why do you always change points, plugs and condenser if the condenser never fails? Last time I ever went to that store.The manual also said to re-torque the head every 1300 miles. I found out the hard way it was because the head gasket would blow at 1305 miles.
Still in all. I loved that car, I cut my teeth on it mechanically and I love Alfas to this day. If I ever hit the Lotto I'm going to blow part of it on a 1938 8C Mille Miglia. And a Tipo 51 Bugatti. The two most beautiful cars made before WWII. IMHO, anyway.
Rick
On Wed, Apr 4, 2018 at 9:46 PM, Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
| Quote: | Oh, Lucus. You buried the lead. And explained all the problems in one word.
Just so you know, it didn't get much better in the intervening 11 years; the '70 Spyder I owned housed a demon who made sure I never knew when it would start. Always turned over, but the bizarre and primitive electro-mechanical injection had a mind (or demon) of its own.
On 4/4/2018 9:11 PM, Richard Girard wrote:
| Quote: | Charlie, You're right, the starter was engaged and running but the minute the engine revved over starting rpm the engine was driving it, too. It's probably no surprise that the car had English electrics, a mix of Smith and Lucas. Me experience with it was too many ghost problems. The horn began to blow one night right as I was on my way out for a date. Disconnected the horn, went on the date and tried to get the horn working the next day. Reconnected it and nothing wrong. Never failed again. Then there was the night the passing lights started flashing on their own. Pulled the whole steering wheel off, went through it, couldn't find anything, put it back together, worked fine. Never failed again. As much as I loved the car I began to think of it as Mussolini's revenge. I didn't know about Lucas then.....
Rick
On Wed, Apr 4, 2018 at 8:14 PM, Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
| Quote: | At 1st glance, I'd suspect there's a flaw in the analysis. If the switch wasn't releasing, then the starter was still powered, regardless of whether the engine could drive it or not. That would mean it was running the entire time the car was running, and starters are not designed for that. Given the obvious lack of knowledge about the car and limited expertise of the people working on it, with that many service operations by those people working on it I'd find it difficult to pick any likely failure mode for the stuff that failed. Just one thought about the failure of the regulator: uninformed installation of the battery, even once.
FWIW,
Charlie
On 4/4/2018 7:49 PM, Richard Girard wrote:
| Quote: | Bob, all, When I graduated high school back in the dark ages I had a 1959 Alfa Romeo Giullietta Spider that had a nightmare starter system. First, the electrical system was positive ground. That alone made things interesting but the starter, or rather the starter switch was the flash point of failure. Why? Because it had no spring return. You had to physically turn the starter motor off or the starter would stay connected with the ring gear and the engine would drive the starter. I was warned by the guy who sold me the car and I only left it engaged once for a few seconds. The grinding sound was kind of a give away and I got away with it. When I sold the car to my best friend I told him what I'd been told, "Never, ever let anyone else drive this car". About four weeks after Dave bought it, he let his step brother drive the car. He left the starter engaged for the entire 10 miles he drove it. The next day, the battery was dead. When checked, it had internal shorts and was junk. Dave bought a new Die Hard, the new thing in battery advertising, if not battery technology. It lasted a couple of weeks and Dave took it back to Sears. The battery was tested and failed. He got a new one. It too failed in short order. This went on for FOUR batteries before the manager at the Arden Way Sears gave my friend a full refund and refused to sell him any more batteries. Somewhere in the mess the starter failed and was replaced, the generator failed, the headlights would burn out on a regular basis and my friend almost became my ex-friend. He was a poor college student trying to fix the car with suggestions from his dad and some mechanics he knew. Finally his folks loaned him the money to take it to a garage that worked on Alfas and they determined that the voltage regulator was fried, too. This had gone on for almost six months before he finally had the car back in a dependable condition. So my take is, yeah, drive the starter and turn it into a generator and things are going to screw up in a major way.
Rick Girard
PS Probably the worst part came when Dave was finally able to enjoy the car again he took it for a drive on a beautiful day. A truck in front of him kicked up a stone that went right through the radiator. He pulled into a service station and the engine rattled to a stop. The kid at the pump popped open the hood and started filling the radiator before Dave could stop him. Put a crack all the way across the roof of the number three combustion chamber.
On Wed, Apr 4, 2018 at 4:37 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 03:46 PM 4/4/2018, you wrote:
| Quote: | | If the bendix gear is sticky, such that the engine is able to drive the starter, I could imagine that it could push a fairly high (albeit short) number of joules back up the wire. Right? |
the 'Bendix' drive is gone. All starters
use direct engagement solenoids.
A return spring retracts the pinion
gear upon removal of power from the
motor. In fact, electrical power to
the motor is interrupted during the initial
retraction so there is no torque being
transmitted from motor to ring gear.
At the same time, an overrun clutch
https://tinyurl.com/y7prvn7b
prevents the accelerating engine
from back-driving the starter. If
this clutch were not present, first
motion of the engine during pinion gear
retraction would break things.
This feature was built into the legacy
'bendix' drive. Starter motor acceleration
working against pinion gear mass would
drive it outward on the shaft by means
of a spiral groove on the shaft . . .
engine acceleration tending to over-run
the starter would drive the pinion back
from the ring gear with the same groove.
[img]cid:part5.C7D05308.20472A9D(at)gmail.com[/img]
There have been some hangar-tales of starter
pinions 'sticking' and back driving starters.
There have been cases of contactor sticking
keeping power on the starter thus maintaining
pinion engagement. But no back driving could
have occurred due to action of the clutch.
Had the motor been driven backwards at the
pinion to ring gear ratio, it would probably
have slung wires out of the armature and/or
stripped gear teeth.
The same gear reduction of pinion-to-ring
allows starter armature to run at several
thousand rpm to generated 200 rpm at the
crankshaft. Okay, after engine start and
run at 1000 rpm, a back-driving situation would
spin the starter armature 10000 rpm plus?
Bob . . .
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--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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--
“Blessed are the cracked, for they shall let in the light.” Groucho Marx
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The smallest miracle right in front of you is enough to make you happy.... |
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jim(at)PoogieBearRanch.co
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| Posted: Thu Apr 05, 2018 7:17 am Post subject: Starter SURGES |
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Ah, Lucas, "The Prince of Darkness"... I had a '63 Austin Healy Sprite
that was graced with his presence... Converted to 12v Negative ground
"US standard" stuff when the engine was replaced... Cost some $$, but
less than the ongoing Lucas part-of-the-week club membership -
especially at "import prices"...
Jim Parker
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