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Old 03-21-2013, 08:49 PM   #1
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DC Amp Meter for Alternator

Hi All,
does anyone have a good tip for an inexpensive DC Amp Meter that I can put "in line" with the output wire of my Balmar High Output Alternator?
It would be good when I am doing an engine room check to just glance at the meter to be sure that my alternator is putting out a good amount of amps to my house bank.

Thanks for any tips,

Taras
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Old 03-21-2013, 10:54 PM   #2
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I think you are saying that you wish to install an additional ammeter in the engine space
If you already have an ammeter on your console which works from a shunt in the charging circuit, you may add additional meters to the same shunt and place them wherever you want withoutand heavy gauge wiring.
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Old 03-22-2013, 07:39 AM   #3
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To expand a bit on the previous poster's comment:

The output from the Balmar alternator can be 100 amps or so. That is too much current to simply hook up an inline ammeter. These are usually limited to 30 amps.

Blue Seas and others make DC ammeters with an external shunt which is installed in the circuit. Then the sense wires, which can be very small, can be run to the meter.

David
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Old 03-23-2013, 09:21 AM   #4
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Quote:
Originally Posted by djmarchand View Post
To expand a bit on the previous poster's comment:

The output from the Balmar alternator can be 100 amps or so. That is too much current to simply hook up an inline ammeter. These are usually limited to 30 amps.

Blue Seas and others make DC ammeters with an external shunt which is installed in the circuit. Then the sense wires, which can be very small, can be run to the meter.

David
Can anyone tell me why my alternator is very hot to the touch and it literally burned the belt!!
Thanks
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Old 03-23-2013, 09:43 AM   #5
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Can anyone tell me why my alternator is very hot to the touch and it literally burned the belt!!
Thanks
The belt was slipping? Look for black dust which is a sure sign of either a belt too loose or too much load for the belt.

David
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Old 03-23-2013, 09:52 AM   #6
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The belt was slipping? Look for black dust which is a sure sign of either a belt too loose or too much load for the belt.

David
I'm not for certain, but I do know that the alternator still spins and it just happend after motor runnin for just 5 minutes...
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Old 03-23-2013, 12:58 PM   #7
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Your alternator pulley may be machined (most are) with a flat at the bottom of the groove. When your belt is worn to a point where it rests on that flat, it will begin to slip and tightening it will not stop it. The heat generated by the slipping is absorbed by the pulley and burns the grease out of the front bearing and it will fail even after the belt is properly replaced. Overtightening the belt overloads other bearings that the belt is on too.
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Old 03-23-2013, 01:05 PM   #8
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Can anyone tell me why my alternator is very hot to the touch and it literally burned the belt!!
Thanks
I just went through a similar happening 3 weeks ago and it was found that I had a short in the windings. The alternator was sent to the shop to be rewound. Was it still charging (volt meter) when you discovered the problem? (Mine wasn't) Even alternators that are functioning correctly get quite warm, but not warm enough to burn the belt. (So I am advised)
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Old 03-23-2013, 01:57 PM   #9
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A bad battery can 'overwork' an alternator resulting in high alternator temps and slipping belt.
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Old 03-23-2013, 03:25 PM   #10
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A bad battery can 'overwork' an alternator resulting in high alternator temps and slipping belt.
Thanks to all for info.... I think I'll pull alternator and have it checked out ... One other question... Should I be switching shore power off if I start motor in the slip
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Old 03-23-2013, 07:44 PM   #11
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................... One other question... Should I be switching shore power off if I start motor in the slip
There's no need to do that.
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Old 03-26-2013, 12:51 AM   #12
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Check the alternator pulley sidwalls. If the slipping has been going on for a while it can wear the sidwalls of the pulley. Then the next belt will have a short life because the pulley sidewalls and the belt do not have a proper fit to each other reducing the friction and allowing slippage again.

Be sure also that the belt is indeed the correct type. I've seen instances where people have put the wrong belt type, cross section, in place and have a very short life. They match the length and the cross section is close to the eye but not close enough for long life or good operation.

It sounds like it will be ok but be sure.
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Old 04-23-2013, 07:28 PM   #13
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I have a powerline 100 amp alternator on a lehman 120... Can anyone tell me if this is a good alternator ? It's 14 volts
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Old 04-24-2013, 06:34 AM   #14
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A slipping belt will heat the alt , and is the usual cause of a frozen front bearing.

Overheat till the gresse departed , then siezes.

Replacement pulleys are easily aviliable machined of cast iron , not just stamped .
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Old 04-24-2013, 08:51 AM   #15
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Jay:

14 v definitely indicates that your alternator is charging.

David
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