On Oct 16, 7:08 pm, "Lew Hodgett" wrote:
"Tim" wrote:
i can appreciate that. But then again, I also had a customer that
was
buying 70a. JBs
and putting them on a kenworth, and wondered why he was burning them
up. found out the guy was pulling an average 116A load, with all his
"chicken lights" etc.

No free lunch is there?



They "looked" the same as a 130 amp JB series, but obviously the
innards wern't strong enough. But he was getting them cheap from
some
supply house's "overstock special".

No, he wasn't getting what he was paying for.

but the price was right...... LOL!

You love to see cheap skates getting it broken off them.

Lew

LOL!

Ye olde "pay me now, or pay me later"

On Oct 16, 5:53 pm, Matt Colie wrote:
Tim wrote:
Red wrote:
Lew Hodgett wrote:
"Red" wrote:
snip
Guys, I'm in a little confusion here. I've run an alternator shop for
the past 30 years, but rest assured, I don't claim to know everything.

if you look back into the 70's your higher level cars (Caddies and
Buicks etc) used a 100A 27si-100 Delco alternator with a rather small
single pulley in 3/8 belt configuration, and they didn't have a
problem eating belts. Lincoln's and Mercs Used a 100 A Motorcraft unit
but did had a slightly wider belt, and had no problem with shedding
rubber.

I can understand using a mis match pulley configuration like a 3/8"
belt on the alternator with a 3/8" pulley and a 1/2" pulley on the
drive source (crankshaft) yes, that will eat belts.

In the past few years we've been installing the cs130 105 a. delco
alternators on mid 70's cars also using a 3/8' belt and pully with no
significant problems.

Granted a 105a Delco will put out about 130 amps on a full load, but
like the 110 a alternators on the yanmars, they don't run a full load
consistently. Once the battery bank is recharged, the alternator
output drops significantly to only an amp pull from the accessories.
So the torque on the belt is dropped considerably.

Any alternator that has to run a full load full time will burn out. If
you are pulling a 110 amp load don't expect a 110 amp alternator to
last very long.

Now if a person is running a heavy unit like a Leece-Neville JB
series, or 30si Delco or some big Niehoff, then yes, I'd say a double
by 1/2" belts and pulley would be manditory. because even then, the
field rotors are so heavy you have a flywheel effect to take into
consideration as well.

But it would still be interesting to know what the OP's alternator
make and pulley configuration is. Then I'd try to help to the best of
my capacity.

BTW, for the past few years, on my 23' Marquis cuddie (228 hp. 350
chevy alpha 1 mercruiser), I'm running a 105a Cs-130 D alternator
(with updated rectifier) , with single 3/8" belt, two batteries. on an
isolator. engine battery is a standard automotive, and the accessory
battery is an 8-D "Cat" battery. I've run the 8-D battery almost dead
several times, and the alternator has charged well, and the belt has
had no significant signs of wear.

Tim,
This is very interesting......
I do boat electrics, that is what I do. www.yachtek.com
I also know a lot (certainly not all) of what you know about old
equipment and applications.

Until the last five years or so, I would have agreed with you
completely. But, I have had it proven to me that about 100amp is all
the 10mm belt that lives on the front of most of the little engines will
take and survive.

I have fit quite a number of cruising auxiliaries with big assed
alternators. Most will eat a belt any time they go over about 100amps.
Unfortunately, this mistake is usually at my expense. Sometimes I can
tune a regulator to limit the charge rate and sometimes I have to get
(or worse make) a new larger sheave to slow the machine down.

Even the 4 cylinder Perkins with a full 1/2 belt are in trouble there,
but less so than the Volvos and Yanmars with 2 and 3 cylinders. If we
look at the differences, there are more than a few, and let's not even
get into automotive.
The smaller belt does us no good at all - Agreed?
The situation is always worse with the lower cylinder count, I attribute
this to the short term variation in crankshaft speed (something a V-8
has almost none of).
Another BIG difference, is that for a cruising auxiliary, you have to
belt the alternator to charge at rated (or best) current at cruising rev
not the rated speed. [One owner routinely blew up the FEAD belt
maneuvering into a slip because he would go to rated then.]
There is squat for airflow in any sailboat engine space.
Sailboats always beat up the batteries more because they always burn
them down and then want to change them completely on the way in the
harbor.

By the by, I have a motorhome that I have used for a mobile shop for a
while, that has a 455 and an 80 amp alternator (the old GM with two
pivot feet instead of a long single). Any time I've run the house
battery down, the alternator squeals for the first couple of miles. A
double belt is a common retro fit in this vehicle even without the 140
amp alternator. I do NOT like changing the inside belt.

Matt Colie- Hide quoted text -

- Show quoted text -

Matt, unfortunately your link doesn't work.....

Tim wrote:
Matt, unfortunately your link doesn't work.....

Tim,
Thanks for the heads up!
Try www.southpointechandler.com
That is the group that I work under
(at least until the new state taxes put us out of business).
I going to have to have our web guy fix the link anyway.
Matt

On Wed, 17 Oct 2007 11:59:26 -0000, Tim wrote:

Any alternator that has to run a full load full time will burn out. If
you are pulling a 110 amp load don't expect a 110 amp alternator to
last very long.

I don't dispute what you say, but I may quibble over terminology.

Maximum load and full load are not exactly the same thing. Full load
is really max continuous, as opposed to short term emergency, load.
What do you think the term 'overload' means? I believe it means enough
more than continuous power to cause overheating. The copper and iron
take time to heat up which is why you can get away with stuff for a
while. They seem to lie about the ratings is all, and the warning is
good.
If you say they all do it, I will keep that in mind. All the AC
electric motors I have wired or used have been good for the rated
power full time, with I think, no more than a 40C temperature rise.
Starter motors put out about ten times what their size indicates they
should and can easily be burnt up if you have a good battery. Thirty
amp generators used to be the size and shape of the starter which
would draw 300 amps or so.

Another question. How can an alternator eat belts if the manufacturer
picks the belt size. Do the crankshaft designers get to pick? the guys
that design those things know how much power a given belt will safely
carry. Do they come with a naked shaft, buy the pulley separately?
Cars are not that way. This takes arithmetic and a catalog, nothing
exotic. A second year engineering student could do it. So can many
shade tree mechanics.

So what gives with belt eating? Is everything as light and cheap as
possible? On cars the things always last at least hundreds of hours.
Spark plugs last 100 000 miles.

Gardner used to build a 250 horsepower, six cylinder, diesel you could
start by hand if the electrics all went west. Too bad you have to buy
a $500 000,used, boat to get one. You can get home after all the
electrics take a dive, which is not true with many power boats. Oil
lamps anyone? Maybe tick tick chronometers and sextants, mechanical
taffrail log and paper charts? Tahiti is, supposedly, easy to find,
the airliner contrails point right to it. Like following roads with a
plane. You don't even need a map. Or so someone said, I never tried
it.

Twelve volts isn't really enough, which is why so many airplanes use
twenty-eight, so called. You can always get by with less copper if you
double the voltage. Less current, smaller wires. The battery can stay
the same size, with more and smaller cells. After all the power it
takes to crank an engine doesn't change, so doubling voltage halves
current and minimum wire size.

Casady

"Richard Casady" wrote:

The copper and iron
take time to heat up which is why you can get away with stuff for a
while.

This is a trick some alternator manufacturers play.

The rating they publish is a "cold" rating which is cheating.

The true rating of an alternator is a "hot" rating.

Try runing an alternator under full load in the Arizona desert in the
summer time if you truly want a test.

Starter motors put out about ten times what their size indicates
they
should and can easily be burnt up if you have a good battery.

Yep, cranking motors are definitely time rated; however there are
exceptions.

When I worked for Leece-Neville, a standard cranking motor test was to
lock the roter of a cranking motor ia a vice, then connect two (2),
fully charged 8D batteries in parallel along with a 600A knife switch,
some 4/0 welding cable and an 8 ft long wooden 2x4.

Secure the switch to the wooden floor, and wire everything up.

One guy stands by with a fire extinguisher, another with the 2x4.

Use the 2x4 to slam the knife switch shut and stsnd back.

The cables would smoke and snake around, leaving burn marks on the
wooden floor, the cranking motor grunts and gets hot until the
batteries are discharged.

When discharged, beat the switch open and wait for things to cool
down.

Next day check out the cranking motor and try to start it.

If it would turn over, it passed.

(You don't run that test very often)

How can an alternator eat belts if the manufacturer
picks the belt size.

I used to do belt and sheave design applications for heavy duty
alternators.

You start with the torque/RPM curve which dictates the required load
the belt/s must handle.

The belt/s chosen dictates the minimum sheave size for the alternator
and minimum angle of wrap.

Given this information, the final design of the drive is the
responsibility of the engine manufacturer.

The big boys have no problem with dual belt drives.

The people in the consumer market are another story.

Lew

On Wed, 17 Oct 2007 11:59:26 -0000, Tim wrote:

accessory
battery is an 8-D "Cat" battery. I've run the 8-D battery almost dead
several times, and the alternator has charged well.

That battery is not actually intended for deep cycling, but is a
starting battery Running it down to flat will damage it, and it only
might only take a few times to do it in. Any battery should be charged
slowly: a ten hour rate is fast. And the slower the discharge rate,
the more total juice you get. I am pretty sure I will get the same
battery for my boat, and I will try not to discharge it to below 75%.
That is not a deep cycle. 25% is deep. Batteries have to be babied,
and if you find one that is more robust, it will be sure to cost more.

Casady

On Fri, 19 Oct 2007 14:47:56 GMT, (Richard
Casady) wrote:

Batteries have to be babied,
and if you find one that is more robust, it will be sure to cost more.

Except for golf cart batteries which seem to break that rule, and yes,
they can be used for starting batteries. I used to spin a pair of 454
cids on my old boat with golf cart batts, never had a problem. They
are also *much* easier to handle than 8Ds.

On Tue, 16 Oct 2007 19:24:51 -0000, Tim wrote:

Any alternator that has to run a full load full time will burn out. If
you are pulling a 110 amp load don't expect a 110 amp alternator to
last very long.

Full load is not the best phrase, I think you really mean maximum
load. Maximum load full time is the issue. Full load should refer to
maximum continuous load, the max the thing can endure forever.

Casady

On Tue, 16 Oct 2007 13:30:16 -0700, Tim wrote:

I've seen many a 130A L/N come in with stators fried to a crisp due to
rotten batteries and/or dubious ground cables. (but usually the pos.
rectifier was toast too!)

I have seen many a fusable link in an alternator output wire. How do
you fry electrical goods with a proper fuse in place? You don't. I
thought there was a voltage regulator. That doesn't protect the
alternator?

Casady

On Fri, 30 Nov 2007 21:08:04 GMT, (Richard
Casady) wrote:

On Tue, 16 Oct 2007 13:30:16 -0700, Tim wrote:

I've seen many a 130A L/N come in with stators fried to a crisp due to
rotten batteries and/or dubious ground cables. (but usually the pos.
rectifier was toast too!)

I have seen many a fusable link in an alternator output wire. How do
you fry electrical goods with a proper fuse in place? You don't. I
thought there was a voltage regulator. That doesn't protect the
alternator?

Casady

No, the normal alternator regulator simply controls the output of the
alternator in reference to battery voltage. Low battery voltage high
output, high voltage low output.

Bruce-in-Bangkok
(Note:remove underscores
from address for reply)