Bob,
I assume that you have the proper belt size for your pulley arrangement. A single belt should be able to handle a 60A alternator. You might check to see that you are using a heavy-duty truck belt. These stretch less than normal belts. Any good automotive parts store can special order these.
http://www.daycoproducts.com/daycoweb.nsf/8264754109ad09a3862571b000513980/76f8220aaa855780862571b00066aed1!OpenDocument

You can expect any belt to stretch when first installed. You should retention after 30 minutes of initial use.

Once a belt has burnished, it should be replaced. Avoid running the engine when the belts are slipping if possible. Reducing engine RPM until you can fix the problem usually saves the belt.

Here’s a link to a belt tensioning tool. I find this to be the best way to tension my belts.
http://www.fastenal.com/web/products/detail.ex?sku=0454182

I have dual-belts on my installation but a much larger alternator. I still must retention my belts every now and then. The tool above makes it easy.

Rich

Post generated from Pearson424 Forum using Mail2Forum

Hi Bob-
Rich makes good points. Perhaps there are a couple other considerations.
We have two 100 amp alternators on a W-58. One is in place of the original with two 1/2″ belts, the other on a bracket on starboard side originally intended for the refrigeration compressor, also two belts.
My experience is that the capacity of the alternator is less important than the load. Your 60 amp alternator if maxed out is a pretty big load for one belt. The max we see is about 150 amps split between two alternators. This only happens for a short time, but we still have to adjust the belts infrequently.
There is a tradeoff between belt contact area and belt tension so for the same load, a single belt will have to be tighter than two belts. The problem is that the belt also drives the water pump and if you make it too tight, the excessive side loading might damage the pump.
For dual belts, you will need a double sheave water pump pulley. You can either buy one from Westerbeke ($$$!) or have a sheave added from another pulley by a machine shop.
Quent
Clairebuoyant, #132

Rich,

Forgive the mechanically challenged among us. How does that Fastenal
belt tensioning tool work? What do you do with it? To tighten an
alternator belt, I’ve always losened the appropriate nuts and jacked the
alternator tighter with a tire iron. Would love to know a better way.

Tor

When I had a W58, I ran a 140 amp alternator on double A belts. No
problems at all.

When you say you are have trouble keeping in belts, what is the pattern
of the failures? Are they edge worn? Double check that the pulleys are
co-planar and that the belts are not bottoming out in the pulleys (wrong
width of belt).

Good luck,

Pete

On 9/5/2012 6:04 AM, Robert Fine wrote:

Hi All,

I have a Westerbeke 58 and I’m having a devil of a time keeping in belts
for the alternator (65 amp). I think I need either two belts (and a bigger
alternator) or a wide serpentine belt – has anyone done that? How do you
lot put 100 amp alternators on without belt slippage? I have the extension
pulley on the crankshaft, but it’s so far away from the engine I’d have to
build a new bracket to use it for anything.

All suggestions helpful and desirable!

Thanks,

Bob

_______________________________________________
maillist mailing list

https://pearson424.org/mailman/listinfo/maillist_pearson424.org

Post generated from Pearson424 Forum using Mail2Forum

Bob
My original W-60 came with an optional high-capacity alternator. The engine was fitted with four extra pulleys. One belt ran the water pump only. Two ran the refrigeration compressor and two ran the alternator. All brackets were fabricated by Pearson or Westerbeke when the boat was built. I had to replace the original high-capacity alternator at one point in time. I found a local supplier who matched the mounting dimensions. The replacement however was a much bigger unit. I had trouble getting the belts tight enough until I found the tool I mentioned.

When I repowered, I had two extra pulleys added to my new Yanmar. The engine comes with just a single 3/8″ belt to drive the stock alternator and water pump. There’s no way that a single belt can drive a 160A alternator. I have a refrigeration compressor too which can at times present as big a load as the alternator. I had to get creative. I fabricated a custom mount for the compressor and alternator. It was a bit of work. Both accessories run using the same pair of belts. The original belt still drives the original alternator and water pump but nothing else.
http://www.richardcarter.net/repower/AccessoryMount.html

You must be careful to avoid excessive side-loads on a crankshaft. The more pulleys you add, the farther off the end of the shaft you’re center of effort will be. A pulley 12″ from the engine face will load the shaft twice as much as one 6″ out. Excessive side-loads can break your crank-shaft. How much side-load is acceptable is hard to determine. Yanmar publishes a complicated formula in their PTO specs. I checked with Yanmar before designing my brackets to make sure that I wouldn’t void my warranty. When tightening belts, its best to remember to get them tight enough but don’t go nuts with a pry-bar.

If all you have is a 60A alternator and water pump, I think you’ll be OK if you get a good belt and properly tension it. Let us know how this works out please.

Regards
Rich

Post generated from Pearson424 Forum using Mail2Forum

Hi Bob,

I upgraded from a 55 amp to a 104, then a 134 the largest
rating I could get in the same form factor. Both the 104 and 134 chewed
up single belts. When I upgraded to a double belts on the alternator,
that problem went away.

Steve

On 05.09.2012 05:04, Robert Fine
wrote:

Hi All,

I have a Westerbeke 58 and I’m having a devil of

a time keeping in belts

for the alternator (65 amp). I think I need

either two belts (and a bigger

alternator) or a wide serpentine belt –

has anyone done that? How do you

lot put 100 amp alternators on

without belt slippage? I have the extension

pulley on the crankshaft,

but it’s so far away from the engine I’d have to

build a new bracket

to use it for anything.

All suggestions helpful and desirable!

Thanks,

Bob

_______________________________________________
maillist mailing list

https://pearson424.org/mailman/listinfo/maillist_pearson424.org

Post generated from Pearson424 Forum using Mail2Forum

I think Rich is correct regarding the problem with side loading. If you can configure the second alternator as close as possible to 180 degrees from the original, much of the side load will cancel out.
We drive both alternators from one Balmar 612 regulator. The regulator sees it as one 200 amp alternator, with four belt drive, minimal side loading as they are about 150 degrees apart, and considerably less cost than a 200 amp unit.
One downside for us, the second alternator, mounted outboard to starboard on the old refrigeration compressor bracket, was not quite rigid enough. On the long motor trip up and back to Florida, the boltholes in the alternator wore considerably, as did the bolt. Now looking for a replacement front case for a Balmar 100 amp alternator.
Quent

Ah,so. Thanks.

Tor

Post generated from Pearson424 Forum using Mail2Forum