what's the condenser for on a mechanical voltage regulator?
hil...@emailaccount.com
'69 Firebird and it started charging his battery again. Even though
he had bought a new voltage regulator a month or so ago. (And then an
alternator.) His does not have the condenser installed on the voltage
regulator like mine does, but there's a terminal for it.
I'm wondering if the condenser is necessary, maybe to keep the
contacts from burning? I'd heard it was to prevent radio
intereference, which we don't care about. I can't find anything in
the service manual about it. If it's necessary to prevent contacts
burning, maybe his new voltage regulator fried its contacts.
Ted Mittelstaedt
<hil...@emailaccount.com> wrote in message
news:1171846931.6...@s48g2000cws.googlegroups.com...
The condensor keeps the points from burning up. When the points break,
for a short time, current keeps flowing in the condensor. So, the points
don't arc. Then when the contacts close the condensor dumps it's
charge across the closed points and is then ready to absorb the current
from the next break.
Ted
jim
I think the main purpose of the condenser was to reduce static on the
radio. Particularly on AM radio.
-jim
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Hustlin' Hank
I could be wrong, but I always thought they were for radio noise only
since most don't have them. The points on the voltage regulator
solenoids don't open and close at over 1000 times per minute like the
igniton points (only when key is turned on/off), therefore they won't
burnt out nearly as quick.
Hank
Bob Flumere
Radio static only.. nothing to do with the charging system,
regulator or contacts inside.. If you don't have an AM radio
in the car you don' t need it.
Bob
Mike Romain
need new ones.... I was always under the impression you needed the
condenser to slow this down.
Sometimes if they have arced while closed, you can thump on the
regulator to get it going again if I remember right. The bad alternator
might have caused this also. Some others you could open and inspect.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)
H...@nospam.nix
"Mike Romain" <rom...@sympatico.ca> wrote in message
news:45d9c1c4$0$5354$9a6e...@unlimited.newshosting.com...
> The points 'do' arc out and burn in those regulators or you wouldn't
> need new ones.... I was always under the impression you needed the
> condenser to slow this down.
You're right, Mike. The condensor is there to stop RFI but it does it by
stopping the sparking, which is an interrupted DC. Just like the condensor
used to do on points, it provides a low impedance path for high frequency
AC or interrupted DC.
While an electromechanical regulator might not be a critical to spark damage
as ignition points were, the principle is similar.
Dan_Thom...@yahoo.com
>
> I could be wrong, but I always thought they were for radio noise only
> since most don't have them. The points on the voltage regulator
> solenoids don't open and close at over 1000 times per minute like the
> igniton points (only when key is turned on/off), therefore they won't
> burnt out nearly as quick.
>
> Hank
Those points DO open and close thousands of times per minute. They
are buzzing constantly, making and breaking contact and forming a
(more or less) square-wave input to the alternator rotor. The
induction of the rotor's coil smooths out the wave somewhat, but also
causes sparking at the regulator points and they will ultimately
either burn out or weld themselves shut. Filing them doesn't help
much; they are silver-faced and once the silver is gone they quickly
fail again.
There is a resistor across the contact points. You'll find it
under the regulator frame, in open air. When the points open, the
current takes the path through the resistor, reducing the current flow
to the rotor and thus reducing the alternator output voltage. If the
voltage gets really high, the regulator's moving contact goes to
ground and takes the rotor current to zero.
The capacitor will reduce radio noise and contact point
erosion, though many regulators will go for years without a capacitor.
The rotor's induction isn't all that great and the resistor absorbs
much of the peaking created by the rotor coil.
After my students wire up the alternator charging systems on
the teaching boards, we can see the constant, tiny spark between the
points if the room is really dark. Those points are moving constantly.
They have to, to keep the voltage exactly where the regulator wants
it. The electronic regulator makes much more sense, modulating the
current instead of repeatedly interrupting it altogether.
I have schematics here of the electromechanical regulator. I
can't find a similar one on the 'net.
Dan
Bob Flumere
To the OP.. you do NOT need this cap.....
It is NOT a functional part of the charging system in any way...
It is only a high frequency bypass to ground for radio noise
suppression.
Its purpose and connection into the circuit in this application does
not affect nor control the arcing at the voltage control contacts...
Having this cap in the circuit (or not) will not damage the regulator
or affect the charging system in any way.
The capacitor on the GM Delco voltage regulator is ONLY for RFI
suppression.. it is not in the "Field" circuit where the altenator
field (rotor) contacts are located.
In the days of generator (as opposed to "alternator" charging systems,
mis-connecting the RFI capacitor to the field terminal of the
generator (an easy mistake to make in the day) would CAUSE a failure
of the voltage control contacts in the regulator!!
The cap in this particular application was mounted on the generator
case, and designed to be connected to the generator "Armature"
terminal which was in fact the current output terminal.
GM DELCO used to put a big round red cardboard warning tag on the
"field" terminal of the generators telling you NOT to connect the
capacitor wire to this (field) terminal!
In this instance, the capacitor was being used to suppress the RFI
from the arcing at the generator brushes which would be heard as a
"whine" on an AM radio..
Of course these two connection terminals were located side by side on
the generator case, and only a few of us could read the big red tag.
So when this mistake was made the voltage regulator failure would
occur within a couple hundred miles. <BG>
These uses are NOT related to the use of a capacitor in "Point +
Condenser ignition system, where the cap serves an entirely
different function in the creation of the High Voltage spark and
in fact does absorb the arc at the contacts that is created
by the collapse of the field in the primary of the ignition coil on
the "break" of the contacts.
Again, I repeat, this capacitor on the Delco Altenator regulator base
is NOT involved in the charging circuit in any way, and only exists to
suppress the RFI generated by the arcing at the vr contacts...
If you look at the back of the regulator base, you will see that the
capacitor terminal is merely an extension of the "B" or Battery
terminal lug. The capacitor from there to ground suppresses any
HF RFI that might be generated from reaching the rest of the car's
electrical system and thence being heard as a "popping" type of
static on an AM radio..
Feel free to ask for more technical explanation an any time.
School is out fo now .. there will be a quiz later <G>
Bob F.
Steve
> Just tried my '66 GTO's mechanical voltage regulator on my friend's
> '69 Firebird and it started charging his battery again. Even though
> he had bought a new voltage regulator a month or so ago. (And then an
> alternator.) His does not have the condenser installed on the voltage
> regulator like mine does, but there's a terminal for it.
>
> I'm wondering if the condenser is necessary, maybe to keep the
> contacts from burning? I'd heard it was to prevent radio
> intereference, which we don't care about.
Both of the above. The regulator is switching an inductive load, which
causes a huge voltage spike (and resulting arc) when you interrupt it by
opening the contacts. The condensor damps out the voltage spike and
prevents the arc. The arc is what causes radio interference.
Steve
Actually, at least one pair of contacts in a voltage regulator DOES
open/close very fast. Maybe even faster than the engine points.
H...@nospam.nix
"Bob Flumere" <rflu...@comcast.net> wrote in message
news:6mvjt2dd1lo7fnkrg...@4ax.com...
> On Mon, 19 Feb 2007 12:43:05 -0600, <H...@nospam.nix> wrote:
>
> >
> >"Mike Romain" <rom...@sympatico.ca> wrote in message
> >news:45d9c1c4$0$5354$9a6e...@unlimited.newshosting.com...
> >> The points 'do' arc out and burn in those regulators or you wouldn't
> >> need new ones.... I was always under the impression you needed the
> >> condenser to slow this down.
> >
> >You're right, Mike. The condensor is there to stop RFI but it does it by
> >stopping the sparking, which is an interrupted DC. Just like the
condensor
> >used to do on points, it provides a low impedance path for high frequency
> >AC or interrupted DC.
> >
> >While an electromechanical regulator might not be a critical to spark
damage
> >as ignition points were, the principle is similar.
> >
> To the OP.. you do NOT need this cap.....
I think we all agree that the capacitor is not functionally required for
this circuit
to function and the car to run.
It serves a purpose (else it would never have been put there) but the
purpose is
not a make or break situation (Well, I guess in one sense of the phrase, it
is
exactly there for 'make and break' situations;>)
jim
Yes, I seem vaguely remember on a generator if you hooked a capacitor to
the field circuit it would actually make the contacts buzz louder.
Hey Bob, Thanks for the info. Somewhere way back when, I think I used to
know all that. But now I think i've reached the point where I've
forgotten way more than I know.
Don
wrote:
You are correct. You beat me to it. Seems like there are a lot of
people out there equating this condensor to condensor as in "points
and condensor." WRONG!!
Mike Romain
>>
>> Again, I repeat, this capacitor on the Delco Altenator regulator base
>> is NOT involved in the charging circuit in any way, and only exists to
>> suppress the RFI generated by the arcing at the vr contacts...
>> If you look at the back of the regulator base, you will see that the
>> capacitor terminal is merely an extension of the "B" or Battery
>> terminal lug. The capacitor from there to ground suppresses any
>> HF RFI that might be generated from reaching the rest of the car's
>> electrical system and thence being heard as a "popping" type of
>> static on an AM radio..
>>
>> Feel free to ask for more technical explanation an any time.
>> School is out fo now .. there will be a quiz later <G>
>>
>>
>>
>> Bob F.
>
> You are correct. You beat me to it. Seems like there are a lot of
> people out there equating this condensor to condensor as in "points
> and condensor." WRONG!!
>
> Don
> www.donsautomotive.com
>
Just how does this condenser affect RF if it doesn't mellow out (buffer)
the arc from the points?
If the points arced closed and stuck from a bad alternator, not having
the condenser on the power feed might have allowed this to happen 'much'
faster than if the buffer action from it was in there, or I am not
remembering right.
H...@nospam.nix
"Don" <d...@NO-SPAMdonsautomotive.com> wrote in message
news:e1lkt2pbf42p4psev...@4ax.com...
>
> You are correct. You beat me to it. Seems like there are a lot of
> people out there equating this condensor to condensor as in "points
> and condensor." WRONG!!
>
> Don
> www.donsautomotive.com
It is more a matter of degree than the electronics behind it for the
regulator.
RFI suppression capacitors can be used at a lot of places where there is
no functional or fundamental need for the.
The need for the capacitor is much more in a Kettering points setup, not so
much for RFI protection but to lengthen the life of the points themselves.
Left alone, the current through the points and the arcing due to this
current
can transfer metal from one face to the other causing early failure.
Dan_Thom...@yahoo.com
There's more to it than that. The arc that jumps the points
as they open represents continued current flow, reducing the sharpness
of the magnetic flux collapse that generates the spark voltage in the
secondary. The condenser provides a temporary path for the electron
flow as the points begin to open, and by the time the capacitor is
full the points are too far apart to start any arcing, and the current
stops much more abruptly. A bad (open) condenser will kill the engine
just as quick as a shorted one.
Just try starting the engine without the condenser installed;
it won't run. Not enough spark. The automotive textbooks I've read
have only the "points-burn prevention" theory as the reason for the
condenser. Not until I studied for my aircraft maintenance engineer's
ticket did I find the real reason for it in the aircraft texbooks. An
old guy once told me many years ago that the (auto) engine wouldn't
run without the condenser; he didn't know why, just that it wouldn't.
I tried it, and sure enough, dead as a doornail.
My Unison/Slick magneto manual says that the condenser also
boosts the mag primary current for the next firing; this is true only
because the magneto generates alternating current for the primary, as
opposed to the DC system in the car.
Dan
jim
Dan_Thom...@yahoo.com wrote:
> There's more to it than that. The arc that jumps the points
> as they open represents continued current flow, reducing the sharpness
> of the magnetic flux collapse that generates the spark voltage in the
> secondary. The condenser provides a temporary path for the electron
> flow as the points begin to open, and by the time the capacitor is
> full the points are too far apart to start any arcing, and the current
> stops much more abruptly.
That's an interesting way of putting it.
The coil capacitor combination form a resonant circuit. When the points
open the output is a very high voltage AC waveform if you don't have it
hooked up to a spark plug. With a spark plug in the secondary circuit
there is a discharge before the AC wave form reaches it's first peak.
Before the points open the condenser is not in the current path. A
capacitor will not pass DC current but does pass AC current.
>A bad (open) condenser will kill the engine
> just as quick as a shorted one.
> Just try starting the engine without the condenser installed;
> it won't run. Not enough spark. The automotive textbooks I've read
> have only the "points-burn prevention" theory as the reason for the
> condenser. Not until I studied for my aircraft maintenance engineer's
> ticket did I find the real reason for it in the aircraft texbooks. An
> old guy once told me many years ago that the (auto) engine wouldn't
> run without the condenser; he didn't know why, just that it wouldn't.
> I tried it, and sure enough, dead as a doornail.
That's right the condenser is designed (by design the correct size is
picked to match the coil) to increase the voltage. The increased
voltage actually increases the arcing at the points simply because more
voltage means more arcing. There is another capacitor that is often
placed on the positive terminal of the coil that is designed to reduce
noise.
-jim
> My Unison/Slick magneto manual says that the condenser also
> boosts the mag primary current for the next firing; this is true only
> because the magneto generates alternating current for the primary, as
> opposed to the DC system in the car.
>
> Dan
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H...@nospam.nix
"jim" <"sjedgingN0sp"@m...@mwt.net> wrote in message
news:11720121...@sp6iad.superfeed.net...\
Kettering will work without a condensor.....for a short period of time. It
has little to do with the series
resonant circuit.
Kettering works by building an electromagnetic field in the coil during the
'make' or 'dwell' portion
of the points. When you open the points, the field decays, and a high
voltage is induced in the coil.
If you have a condensor which is badly out of range, or none at all, the
points will be compromised.
If you have a shorted condensor, then you get nothing.
jim
H...@nospam.nix wrote:
>
> "jim" <"sjedgingN0sp"@m...@mwt.net> wrote in message
> news:11720121...@sp6iad.superfeed.net...\
>
> Kettering will work without a condensor.....for a short period of time.
It will work at a much much lower voltage. The points themselves and the
wiring have some capacitance but it needs more.
> It
> has little to do with the series
> resonant circuit.
As I said remove the spark plug and you have a resonant circuit that
will produce an AC waveform at the resonant frequency. Hook up an
O-scope and try it if you don't believe me.
>
> Kettering works by building an electromagnetic field in the coil during the
> 'make' or 'dwell' portion
> of the points. When you open the points, the field decays, and a high
> voltage is induced in the coil.
>
> If you have a condensor which is badly out of range, or none at all, the
> points will be compromised.
No they won't they will last forever because the engine won't run.
-jim
>
> If you have a shorted condensor, then you get nothing.
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H...@nospam.nix
>
>
> H...@nospam.nix wrote:
> >
> > "jim" <"sjedgingN0sp"@m...@mwt.net> wrote in message
> > news:11720121...@sp6iad.superfeed.net...\
> >
> > Kettering will work without a condensor.....for a short period of time.
>
> It will work at a much much lower voltage. The points themselves and the
> wiring have some capacitance but it needs more.
It works at a lower voltage because the inductive field has to collapse very
quickly
to give highest voltage. It cannot do that if the points are sparking.
> As I said remove the spark plug and you have a resonant circuit that
> will produce an AC waveform at the resonant frequency. Hook up an
> O-scope and try it if you don't believe me.
I am well aware that you will get a ringing waveform when the field
collapses.
> No they won't they will last forever because the engine won't run.
I have never tried it, actually, but concede that if it should start at all,
it wouldnt run for long. Have you actually ever tried this?
Dan_Thom...@yahoo.com
I did. It won't run.
Dan
jim
H...@nospam.nix wrote:
>
> > As I said remove the spark plug and you have a resonant circuit that
> > will produce an AC waveform at the resonant frequency. Hook up an
> > O-scope and try it if you don't believe me.
>
> I am well aware that you will get a ringing waveform when the field
> collapses.
Not usually. If there is a spark plug that fires the wave form gets
arrested before it reaches maximum on it first peak. Only if there is no
diversion of the current (by arcing in the secondary) will there be the
damped sinusoidal waveform.
>
> > No they won't they will last forever because the engine won't run.
>
> I have never tried it, actually, but concede that if it should start at all,
> it wouldnt run for long. Have you actually ever tried this?
Oh sure I have. Remember the type of points that had a condenser wire
that just slipped in behind the points spring. After installing new
points I once put the distributor cap and pinched the condenser wire
between the cap and distributor. The engine started up and idled fine,
but as soon as it was revved up the engine stalled and would not
restart. When I open the distributor I found that as soon as the vacuum
advance kicked in it pulled the condenser wire out of the circuit and
the engine killed. After inserting the condenser wire back where it
belonged and carefully routing the wire so that the cap didn't pinch it
again the engine started and ran fine. With out the condenser hooked up
it had a little spark, but the spark was very weak.
Now I'll admit that the weak spark (low voltage) does have something
to do with arcing at the points and you could probably design a set up
that got a higher voltage with a different type point and coil
configuration. So it may be possible to construct a point set up that
worked without a condenser and that set up would probably not last as
long. But that has to do with efficiency. The capacitor is sized so that
it works efficiently. That is it produces the required high voltage with
a minimum amount of current flow. A system without the condenser would
require alot more current flow thru the coil to generate the same high
voltage output, and thus the points and coil would not last as long.
-jim
hil...@emailaccount.com
jim wrote:
> With out the condenser hooked up
> it had a little spark, but the spark was very weak.
I showed this same thing in a different way trying to test the coil on
my Sportster motorcycle. Used a plain piece of wire instead of points
and condenser, touching the wire to ground manually and pulling it off
to create the spark, seen by looking at a spark plug out in the open
(grounded to the threads, of course). The spark generated in this
manner was so puny it was hardly visible. When I added a condenser
the spark was big and audible.
aarcuda69062
<1172078658.2...@q2g2000cwa.googlegroups.com>,
hil...@emailaccount.com wrote:
Try he same thing but do the make/break by scratching the wire
across a file. Plenty hot spark...
Then again, Chrysler service manuals in the late 70s early 80s
showed how to rig up a coil tester that used a condenser in
parallel with the make/break wire.
Steve
>>
> Ok, so now you have me curious.
>
> Just how does this condenser affect RF if it doesn't mellow out (buffer)
> the arc from the points?
It does. Yes, the charging circuit will WORK without the cap, but the
contacts on the relay will erode much faster than when the cap is
present. Lots of RFI is a sign that the points are arcing, eliminating
or reducing the arcing will make the contact points last longer. No
"ifs, ands, or buts."
jenglish
perhaps you could help me, recently replaced generator and regulator in 56
Buick and ammeter shows no charge again. flashing for polarity doesn't help
anymore. i have a battery disconnect on the ground terminal. with the old
generator and regulator if i did the battery disconnect while the engine was
running the engine would continue to run until the ignition switch was turned
off; since change of generator and regulator when i open the battery
disconnect the engine stops; just trying to understand whats going on. any
comment?
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Kevin Bottorff
news:egNeD.62028$Yw.4...@fx31.am4:
>
>
the first obvious thing is the gen. is not having any output. you need to
find out if its the gen or reg that is the problem. KB
Elvin Opel mechanic
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