More alternator questions

[Don Bradner]

Since we arrived home it has been extremely wet, making me not want to do much
about removing the rear alternator. Today, though, I did pull the plate under
the bed and remove the front alternator. It turns out to be a Prestolite
130-amp, which makes me wonder if it has been replaced, since it is spec'd as a
Motorola 160-amp.

I took it to a local automotive electrical shop, and they got no output on the
bench. They will dissassemble it tomorrow and give me a price to rebuild so I
can decide whether to do that or buy a new one.

Now the question: There was a wire connected to one of the three alternator
stator contacts? What was this? Tach maybe?

Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA

[Leroy Eckert]

Don, one of my wires affects the tach on the #1 alternator. You can almost bet
that someone replaced the alternator along the way with a lower output
alternator. As previously posted, I found a lower rated alternator in my #2
position. I elected to spend the money an put factory spec alternators on the
coach. I have been fine since the change.

Leroy Eckert
1990WB-40"Smoke N Mirrors'
Niceville, FL


----- Original Message -----
From: Don Bradner
To: wanderlodge@yahoogroups.com ; WanderlodgeForum@yahoogroups.com
Sent: Monday, February 26, 2007 8:50 PM
Subject: [WanderlodgeForum] More alternator questions


Since we arrived home it has been extremely wet, making me not want to do much
about removing the rear alternator. Today, though, I did pull the plate under
the bed and remove the front alternator. It turns out to be a Prestolite
130-amp, which makes me wonder if it has been replaced, since it is spec'd as a
Motorola 160-amp.

I took it to a local automotive electrical shop, and they got no output on the
bench. They will dissassemble it tomorrow and give me a price to rebuild so I
can decide whether to do that or buy a new one.

Now the question: There was a wire connected to one of the three alternator
stator contacts? What was this? Tach maybe?

Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA





[Non-text portions of this message have been removed]

[krminyl@...]

I replaced my alternator about a year ago with a Delco 160amp...I had to
lengthen the heavy gauge battery cable about a foot, since the delco was smaller
than the Prestolite that I removed, and the lug was on the far side of the
alternator. I think my BB came with the 130a Prestolite when it was new.
BTW, the new Delco cost around $220, and I kept the Prestolite as a spare.

Kevin McKeown
1986 38' PT
Yorba Linda (raining), CA



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[krminyl@...]

Mike,

No, I didn't splice it....it wanted to, because it would have been a lot
easier, but I think I did it right. I used heavy gauge wire (used for welding
cables), crimped and soldered on new lugs, drilled a new hole in the bulkhead
with a new smooth metal grommet, and fed the new cable into the compartment
where the battery chargers/shunts/etc are. I also made sure that the new
cable was securely mounted along it path from the alternator to the compartment
with stainless steel insulated clamps. Anyone should be a little paranoid
when dealing with this high amp current...it's the thing that can cause things
to burn up!!. The cable was a little difficult to manage, but I'm sure it was
worth the hassle.

Kevin McKeown
YL CA
1986 38' P



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[Mike Hohnstein]

When you say you lengthened the cable a foot, you replaced the cable, right? I
don't think long term service will be that great with a splice in the cable,
makes resistance, alternators don't like that in my experience.
MH
----- Original Message -----
From: krminyl@...
To: WanderlodgeForum@yahoogroups.com
Sent: Tuesday, February 27, 2007 10:06 AM
Subject: Re: [WanderlodgeForum] More alternator questions


I replaced my alternator about a year ago with a Delco 160amp...I had to
lengthen the heavy gauge battery cable about a foot, since the delco was
smaller
than the Prestolite that I removed, and the lug was on the far side of the
alternator. I think my BB came with the 130a Prestolite when it was new.
BTW, the new Delco cost around $220, and I kept the Prestolite as a spare.

Kevin McKeown
1986 38' PT
Yorba Linda (raining), CA



**************************************
AOL now offers free
email to everyone. Find out more about what's free from AOL at
http://www.aol.com.

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

[Mike Hohnstein]

You did well.
MH
----- Original Message -----
From: krminyl@...
To: WanderlodgeForum@yahoogroups.com
Sent: Tuesday, February 27, 2007 10:54 AM
Subject: Re: [WanderlodgeForum] More alternator questions


Mike,

No, I didn't splice it....it wanted to, because it would have been a lot
easier, but I think I did it right. I used heavy gauge wire (used for welding
cables), crimped and soldered on new lugs, drilled a new hole in the bulkhead
with a new smooth metal grommet, and fed the new cable into the compartment
where the battery chargers/shunts/etc are. I also made sure that the new
cable was securely mounted along it path from the alternator to the
compartment
with stainless steel insulated clamps. Anyone should be a little paranoid
when dealing with this high amp current...it's the thing that can cause things
to burn up!!. The cable was a little difficult to manage, but I'm sure it was
worth the hassle.

Kevin McKeown
YL CA
1986 38' P



**************************************
AOL now offers free
email to everyone. Find out more about what's free from AOL at
http://www.aol.com.

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]

[Don Bradner]

I decided to replace both of my alternators with a new, matched pair. I still
haven't pulled the one by the bumper, but I know the other was only 130 amps and
I want to get back to spec.

My choice was the Leece-Neville triple-nickel common truck alternator in the
160-amp version, 110-555JHO (also known as 8LHA2070VE). I debated going up to
the latest version, which is a 170-amp 110-775 that has a higher heat rating.
Prior to 2004, the 555 was rated to 200 degrees, while the 555JHO is rated to
220 degrees and the new 775 is rated to 230 degrees. I have some suspicion that
failures may partly be due to the high heat of the 8V92, but I'm thinking the
extra 20 degrees may be enough, and the price difference for 10 degrees more is
too much.

Online from http://www.fleetsource.com the 555JHO is $171 plus shipping. I prefer to
buy local if they are in the ballpark, and my local auto-electric folks came in
at $211 which was good enough for me. They hit three of their sources, all of
whom had it in stock, before arriving at that as the best price; my tellling
them that Fleetsource was $171 probably helped them not stop at the first one.

They should be here in a couple of days.


Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA

[Gregory OConnor]

Don, are all alternators designed to spin at the same RPM? if they
are then swapping the same pully will do. I wonder if pully/alt
swaps on BlueThunder in the past leave you with rpm issues? I'll try
and measure my drive pully and alt pully today and post.
GregoryO'Connor
94ptRomolandCa

--- In WanderlodgeForum@yahoogroups.com, "Don Bradner"
wrote:
>
> I decided to replace both of my alternators with a new, matched
pair. I still haven't pulled the one by the bumper, but I know the
other was only 130 amps and I want to get back to spec.
>
> My choice was the Leece-Neville triple-nickel common truck
alternator in the 160-amp version, 110-555JHO (also known as
8LHA2070VE). I debated going up to the latest version, which is a 170-
amp 110-775 that has a higher heat rating. Prior to 2004, the 555 was
rated to 200 degrees, while the 555JHO is rated to 220 degrees and
the new 775 is rated to 230 degrees. I have some suspicion that
failures may partly be due to the high heat of the 8V92, but I'm
thinking the extra 20 degrees may be enough, and the price difference
for 10 degrees more is too much.
>
> Online from http://www.fleetsource.com the 555JHO is $171 plus shipping. I
prefer to buy local if they are in the ballpark, and my local auto-
electric folks came in at $211 which was good enough for me. They hit
three of their sources, all of whom had it in stock, before arriving
at that as the best price; my tellling them that Fleetsource was $171
probably helped them not stop at the first one.
>
> They should be here in a couple of days.
>
>
> Don Bradner
> 90 PT40 "Blue Thunder"
> Eureka, CA
>

[Don Bradner]

You can spin an alternator at any RPM up to its max (8000 continuous on the
triple-nickels). Alternators vary in how much power they produce across the RPM
range.

Alternators made for heavy truck use have performance curves that give good
output at low RPMs. The 110-555JHO produces 50 amps at 1500, 100 amps at 2000,
and 140 amps at 3000. Full 160 amp production doesn't occur until 6000 RPM.

The rear, crank-driven alternator on mine has a pulley ratio of roughly 4:1
(hard place to get a measurement on the crank pulley). That would mean I should
get over 100 amps at idle. The front alternator is not crank driven, and the
pulley ratio is much smaller; I can only assume that the takeoff is rotating
faster than the crank.

I have seen no indication of tach/RPM problems, so I suspect the same pulley has
been used since the beginning. Alternators are sold without pulleys, normally,
so someone would have had to have gone out of their way to replace the original
one.

On 2/28/2007 at 4:18 PM Gregory OConnor wrote:

>Don, are all alternators designed to spin at the same RPM? if they
>are then swapping the same pully will do. I wonder if pully/alt
>swaps on BlueThunder in the past leave you with rpm issues? I'll try
>and measure my drive pully and alt pully today and post.
>GregoryO'Connor
>94ptRomolandCa


Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA