The Murphy Builders Site

Posted: **Sun Feb 19, 2012 4:05 pm**

The ONLY internally regulated unit that I would consider to have
acceptable overvoltage protection is from Plane Power. They add
additional simple crowbar circuitry. Most modern regulator ic's claim OV
protection but once the ic has failed to regulate you can bet the same
ic is not going to reliably protect anything. That has been learned the
hard way.

http://www.plane-power.com/images/inter ... mation.pdf

I use a separate crowbar module to trip a contactor and disconnect the
alternator. Bob Knuckolls of the aeroelectric connection has an
improved version of that system in the works that should be every bit
as good as what plane power sells. Frankly if you have at least one
magneto or similar, I think it is quite reasonable to use any internally
regulated alternator. I was not prepared to risk it with my EFI engine
though. Some guys with expensive avionics have also wished they'd
installed OV protection...

Ken

Walter Klatt wrote:

With my new engine, I am getting a 40 amp internally regulated Lamar
alternator. Can anyone tell me if this internal regulator also provides for
over voltage protection? My new LSE EI system requires over voltage
protection.

Walter

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Posted: **Sun Feb 19, 2012 4:05 pm**

Thanks, Ken. That Plane Power unit is one of the ones that I was looking at,
but my panel wires/fuses, etc were not designed for 60 amps, so I went with
the 40 amp Lamar unit.

I was searching on the internet, and thought I saw some kind of cheap (about
1 dollar) device that could be used to protect a circuit. I think it was
called Transport or something like that and saw it in the aeroelectrics
list. I looked again, but couldn't find it. I also remember seeing some
discussion by someone else saying that it really wasn't necessary, and your
normal internal regulator should be enough.

The LSE instructions say to wire the power supply directly to the + battery
terminal. I think the intent is to buffer the voltage with the battery, as
well as have less radio noise.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Sunday, October 28, 2007 5:21 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Internally regulated alternators

The ONLY internally regulated unit that I would consider to have
acceptable overvoltage protection is from Plane Power. They add
additional simple crowbar circuitry. Most modern regulator ic's claim OV
protection but once the ic has failed to regulate you can bet the same
ic is not going to reliably protect anything. That has been learned the
hard way.

http://www.plane-power.com/images/inter ... ental%20al
ternator%20information.pdf

I use a separate crowbar module to trip a contactor and disconnect the
alternator. Bob Knuckolls of the aeroelectric connection has an
improved version of that system in the works that should be every bit
as good as what plane power sells. Frankly if you have at least one
magneto or similar, I think it is quite reasonable to use any internally
regulated alternator. I was not prepared to risk it with my EFI engine
though. Some guys with expensive avionics have also wished they'd
installed OV protection...

Ken

Walter Klatt wrote:

With my new engine, I am getting a 40 amp internally regulated Lamar
alternator. Can anyone tell me if this internal regulator also provides for
over voltage protection? My new LSE EI system requires over voltage
protection.

Walter

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Posted: **Sun Feb 19, 2012 4:05 pm**

I found the article again that I was referring to. They are called
Transorbs.
http://aeroelectric.com/articles/spike.pdf

B&C sells an over voltage crowbar unit for 35 bucks. Would this be a better
solution to protect everything? Not sure how to wire it, but assume it must
have some way to disconnect the alternator.
http://www.bandc.biz/cgi-bin/ez-catalog ... ?26X358218
Scroll down to OVM-14.

Again, still not sure if all this is necessary.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Walter
Klatt
Sent: Sunday, October 28, 2007 4:53 PM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Internally regulated alternators

Thanks, Ken. That Plane Power unit is one of the ones that I was looking at,
but my panel wires/fuses, etc were not designed for 60 amps, so I went with
the 40 amp Lamar unit.

I was searching on the internet, and thought I saw some kind of cheap (about
1 dollar) device that could be used to protect a circuit. I think it was
called Transport or something like that and saw it in the aeroelectrics
list. I looked again, but couldn't find it. I also remember seeing some
discussion by someone else saying that it really wasn't necessary, and your
normal internal regulator should be enough.

The LSE instructions say to wire the power supply directly to the + battery
terminal. I think the intent is to buffer the voltage with the battery, as
well as have less radio noise.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Sunday, October 28, 2007 5:21 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Internally regulated alternators

The ONLY internally regulated unit that I would consider to have
acceptable overvoltage protection is from Plane Power. They add
additional simple crowbar circuitry. Most modern regulator ic's claim OV
protection but once the ic has failed to regulate you can bet the same
ic is not going to reliably protect anything. That has been learned the
hard way.

http://www.plane-power.com/images/inter ... ental%20al
ternator%20information.pdf

I use a separate crowbar module to trip a contactor and disconnect the
alternator. Bob Knuckolls of the aeroelectric connection has an
improved version of that system in the works that should be every bit
as good as what plane power sells. Frankly if you have at least one
magneto or similar, I think it is quite reasonable to use any internally
regulated alternator. I was not prepared to risk it with my EFI engine
though. Some guys with expensive avionics have also wished they'd
installed OV protection...

Ken

Walter Klatt wrote:

With my new engine, I am getting a 40 amp internally regulated Lamar
alternator. Can anyone tell me if this internal regulator also provides for
over voltage protection? My new LSE EI system requires over voltage
protection.

Walter

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Posted: **Sun Feb 19, 2012 4:05 pm**

The solid state spike protectors (transorbs etc.) do exactly that. They
will tame a momentary spike if you believe there really is such a thing.
They are useless for a real overvoltage though as they will fry in a
fraction of a second with that kind of energy going into them. Yes a
large battery will slow the voltage rise but stuff is still going to fry
in a few seconds or so. Some guys feel they can manually shut off their
alternator in a few seconds if they have a high voltage warning. I'm
very skeptical as it will likely take longer to identify what is
happening but in any case there is no way to shutdown a runaway internal
regulating alternator unless you have a contactor to disconnect it or a
big panel mounted CB (which is generally a bad idea).

Most electrical systems would need little if any upgrading to handle a
60 amp alternator. At most - a heavier wire to the starter or battery
and a larger alternator CB or fuse. Good design often means you already
have the heavier wire and CB as there are good reasons to oversize those
two components..

One of the reasons that I used a small 40 amp alternator was for the
smaller current in the event of a runaway alternator.

The OV risk is low but real and there have been some heated discussions.
I've had one real OV on my secondary John Deere alternator and I'm glad
I had the protection. It was on the ground and a direct result of
starting the engine with one of my two wee batteries stone dead. The
battery wouldn't accept current and the regulator couldn't handle the
situation.

Do you have one magneto or self sustaining P-mag (or is it E-mag?)? If
not and you are not worried about avionics, there is another way to
accomplish the protection if you are going to add a second battery
anyway. $20. of parts would simply automatically isolate the second
battery from the alternator.

Ken

Walter Klatt wrote:

Thanks, Ken. That Plane Power unit is one of the ones that I was looking at,
but my panel wires/fuses, etc were not designed for 60 amps, so I went with
the 40 amp Lamar unit.

I was searching on the internet, and thought I saw some kind of cheap (about
1 dollar) device that could be used to protect a circuit. I think it was
called Transport or something like that and saw it in the aeroelectrics
list. I looked again, but couldn't find it. I also remember seeing some
discussion by someone else saying that it really wasn't necessary, and your
normal internal regulator should be enough.

The LSE instructions say to wire the power supply directly to the + battery
terminal. I think the intent is to buffer the voltage with the battery, as
well as have less radio noise.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Sunday, October 28, 2007 5:21 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Internally regulated alternators

The ONLY internally regulated unit that I would consider to have
acceptable overvoltage protection is from Plane Power. They add
additional simple crowbar circuitry. Most modern regulator ic's claim OV
protection but once the ic has failed to regulate you can bet the same
ic is not going to reliably protect anything. That has been learned the
hard way.

http://www.plane-power.com/images/inter ... ental%20al
ternator%20information.pdf

I use a separate crowbar module to trip a contactor and disconnect the
alternator. Bob Knuckolls of the aeroelectric connection has an
improved version of that system in the works that should be every bit
as good as what plane power sells. Frankly if you have at least one
magneto or similar, I think it is quite reasonable to use any internally
regulated alternator. I was not prepared to risk it with my EFI engine
though. Some guys with expensive avionics have also wished they'd
installed OV protection...

Ken

Walter Klatt wrote:

With my new engine, I am getting a 40 amp internally regulated Lamar
alternator. Can anyone tell me if this internal regulator also provides for
over voltage protection? My new LSE EI system requires over voltage
protection.

Walter

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Posted: **Sun Feb 19, 2012 4:05 pm**

Yes, I am still using one mag, so at worst, my engine won't quit. My panel
is my "own" design, and I know at the very least, I would need a heavier alt
wire and some fuses. And I can't remember what the wires were around my
amp/volt meter. I am really trying to avoid taking my panel apart with the
new engine. But if I did it again, for sure, I would make changes.

Lots of discussions and opinions on the net about this, but for now, I think
I am inclined to just take my chances with the internally regulated
alternator.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Sunday, October 28, 2007 6:46 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Internally regulated alternators

The solid state spike protectors (transorbs etc.) do exactly that. They
will tame a momentary spike if you believe there really is such a thing.
They are useless for a real overvoltage though as they will fry in a
fraction of a second with that kind of energy going into them. Yes a
large battery will slow the voltage rise but stuff is still going to fry
in a few seconds or so. Some guys feel they can manually shut off their
alternator in a few seconds if they have a high voltage warning. I'm
very skeptical as it will likely take longer to identify what is
happening but in any case there is no way to shutdown a runaway internal
regulating alternator unless you have a contactor to disconnect it or a
big panel mounted CB (which is generally a bad idea).

Most electrical systems would need little if any upgrading to handle a
60 amp alternator. At most - a heavier wire to the starter or battery
and a larger alternator CB or fuse. Good design often means you already
have the heavier wire and CB as there are good reasons to oversize those
two components..

One of the reasons that I used a small 40 amp alternator was for the
smaller current in the event of a runaway alternator.

The OV risk is low but real and there have been some heated discussions.
I've had one real OV on my secondary John Deere alternator and I'm glad
I had the protection. It was on the ground and a direct result of
starting the engine with one of my two wee batteries stone dead. The
battery wouldn't accept current and the regulator couldn't handle the
situation.

Do you have one magneto or self sustaining P-mag (or is it E-mag?)? If
not and you are not worried about avionics, there is another way to
accomplish the protection if you are going to add a second battery
anyway. $20. of parts would simply automatically isolate the second
battery from the alternator.

Ken

Walter Klatt wrote:

Thanks, Ken. That Plane Power unit is one of the ones that I was looking

at,

but my panel wires/fuses, etc were not designed for 60 amps, so I went with
the 40 amp Lamar unit.

I was searching on the internet, and thought I saw some kind of cheap

(about

1 dollar) device that could be used to protect a circuit. I think it was
called Transport or something like that and saw it in the aeroelectrics
list. I looked again, but couldn't find it. I also remember seeing some
discussion by someone else saying that it really wasn't necessary, and your
normal internal regulator should be enough.

The LSE instructions say to wire the power supply directly to the + battery
terminal. I think the intent is to buffer the voltage with the battery, as
well as have less radio noise.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Sunday, October 28, 2007 5:21 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Internally regulated alternators

The ONLY internally regulated unit that I would consider to have
acceptable overvoltage protection is from Plane Power. They add
additional simple crowbar circuitry. Most modern regulator ic's claim OV
protection but once the ic has failed to regulate you can bet the same
ic is not going to reliably protect anything. That has been learned the
hard way.

http://www.plane-power.com/images/inter ... mental%20a

l

ternator%20information.pdf

I use a separate crowbar module to trip a contactor and disconnect the
alternator. Bob Knuckolls of the aeroelectric connection has an
improved version of that system in the works that should be every bit
as good as what plane power sells. Frankly if you have at least one
magneto or similar, I think it is quite reasonable to use any internally
regulated alternator. I was not prepared to risk it with my EFI engine
though. Some guys with expensive avionics have also wished they'd
installed OV protection...

Ken

Walter Klatt wrote:

With my new engine, I am getting a 40 amp internally regulated Lamar
alternator. Can anyone tell me if this internal regulator also provides

for

over voltage protection? My new LSE EI system requires over voltage
protection.

Walter

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Posted: **Sun Feb 19, 2012 4:05 pm**

Oops I missed a couple of your posts Walter.

The B&C crowbar unit (or a homemade one) is essentially just a trigger.
It will ground out and trip a circuit breaker or a relay. For an
external regulator it would normally trip the breaker supplying field
current. At the present time, the only way to use it with an internal
regulator is to have it trip a contactor that would disconnect the
alternator.

My first choice would be the plane power alternator. My second choice
would probably be to ignore the OV protection since your engine will run
without electricity. With a lot of avionics or for IFR, I'd want the OV
protection one way or the other and plane power is the easiest way to
get it.

Ken

Walter Klatt wrote:

I found the article again that I was referring to. They are called
Transorbs.
http://aeroelectric.com/articles/spike.pdf

B&C sells an over voltage crowbar unit for 35 bucks. Would this be a better
solution to protect everything? Not sure how to wire it, but assume it must
have some way to disconnect the alternator.
http://www.bandc.biz/cgi-bin/ez-catalog ... ?26X358218
Scroll down to OVM-14.

Again, still not sure if all this is necessary.

Walter

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