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Author Topic: Generator Conversion to Altenator  (Read 606 times)
thekid745
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« on: August 08, 2014, 03:51:40 PM »

I have a 69' GM Fishbowl with a 6V71. I need the generator rebuilt. Is there a kit to convert it to a alternator and is it worth doing?

If not does anyone know where a good place in California is to get this rebuilt?
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shelled
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« Reply #1 on: August 08, 2014, 09:39:34 PM »

if GM transits have same type generator as parlor coaches, in 1969 what you already have is an "alternator" in common parlance.

edward
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Rampside/UltraVan/Excalibur/4104/4107/etc -- Dallas Tx
chessie4905
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« Reply #2 on: August 09, 2014, 05:51:36 AM »

   If your voltage regulator is almost 1 foot square by  about4 inches deep, you have a generator. If it is significantly smaller, it is an alternator. It should have an alternator. What does it need? Bearings or quit charging or properly?
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GMC h8h 649#028
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thekid745
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« Reply #3 on: August 09, 2014, 06:13:29 AM »

It is no longer charging. Where can I find the regulator on this?
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thekid745
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« Reply #4 on: August 09, 2014, 06:27:45 AM »

Here is a picture of it. I was under the impression this was a generator.
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wildbob24
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« Reply #5 on: August 09, 2014, 09:05:54 AM »

Kid,

You have an AC-Delco 50DN. Although GM calls it a generator in the books, it's really an alternator. You can test it by momentarily connecting battery voltage to the Field terminal, with the engine running. If the alternator is OK, it will go to full charge and you'll hear it load down the engine. You won't need to hold it long, maybe 5-10 seconds.

According to the book I have, which is older than your bus, the voltage regulator is located on the blower control panel, which is, and I quote: "on the forward side of the emergency door bulkhead on Suburban models". GM didn't change much over the years, so that should apply to your bus. This assumes that nothing was modified or moved during the conversion process.

Bob
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P8M4905A-1308, 8V71 w/V730
Custom Coach Conversion
Duluth, GA
bevans6
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« Reply #6 on: August 09, 2014, 10:01:57 AM »

Probably the first thing to check, even before the test described above, is to see if there is any voltage on the F terminal, or Field terminal.  This is an output from the voltage regulator that turns the alternator on so it can charge.  If there is no voltage there, check the Battery terminal on the voltage regulator, it should have battery voltage on it, and check that the regulator has a good ground connection.  It's not that common for the actual alternator to fail, although it does happen, but wiring, switching, relay problems to the regulator are common, and a bad voltage regulator is always a possibility.

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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gus
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« Reply #7 on: August 09, 2014, 01:29:17 PM »

What Brian said.

I'm going through this right now with mine, it isn't getting full voltage to the P terminal of the voltage regulator. When I jump directly from the batt to P it works fine.

The VR and wiring are almost always the cause of alt problems, these alternators are really rugged.
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PD4107-152
PD4104-1274
Ash Flat, AR
TomC
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« Reply #8 on: August 09, 2014, 03:09:20 PM »

I had my 50DN exchanged for an updated one and changed my transistorized (a black box that's about 12" x 5") regulator for a digital regulator that's about the size of a pack of cigs. Cost right at $1,500. If you're going to have an inverter to power an A/C going down the road, the 50DN will do it. Otherwise, you could remove the 50DN and install a 2 groove v-belt pulley and use a 160amp truck type alternator that costs about $160.00.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
thekid745
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« Reply #9 on: August 10, 2014, 08:09:49 AM »

I have around 11.9 volts coming off the generator/alternator. This is too low correct?

I will try to find the regulator today, but not sure where it is.

Bob-I don't have a emergency door but I will look in the area it would be if it was to have one.  Thanks for the help!
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bevans6
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« Reply #10 on: August 10, 2014, 08:53:19 AM »

That may be a bad diode in the alternator's rectifier section.  There are six diodes, and they can be tested with a DVM Ohmeter, and they can be replaced quite easily.

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Spicer 8844 4 speed Zen meditation device
Vintage race cars -
1978 Lola T440 Formula Ford
1972 NTM MK-4 B/SR
thekid745
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« Reply #11 on: August 10, 2014, 09:01:50 AM »

Hi Brian,

Where can I find the rectifier section so I can test those diodes?

Thanks,
Dan
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eagle19952
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« Reply #12 on: August 10, 2014, 09:25:02 AM »

Hi Brian,

Where can I find the rectifier section so I can test those diodes?

Thanks,
Dan


http://apra.org/membership/divisions/eldivwebsite/protected/delco/pdfs/service_manuals/legacy/1G-256.pdf

http://delcoremy.com/Documents/Alternator-Service-Manuals/50DN-CAST-ALUMINUM-END-COVER-REPLACEMENT.aspx

http://delcoremy.com/Documents/Alternator-Service-Manuals/50DN-DIODE-REPLACEMENT.aspx

« Last Edit: August 10, 2014, 09:43:02 AM by eagle19952 » Logged
gus
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« Reply #13 on: August 10, 2014, 02:42:45 PM »

11.9 v is a fully discharged battery. Maybe this is your problem?

Before you go testing anything internal make sure the VR is doing its job since it is by far the most common source of problems.

I don't know where your VR is located but on a 4104 it is at the fight rear elect panel and on a 4107 it is right above the batt box. It is a black thing about the size of a brick.

First check that the VR is properly grounded at the G terminal.

With the engine running;

Check the P terminal to make sure it is receiving full batt voltage. If there is any doubt connect it directly to the batt.

If so, check the F terminal for around 10v+-.

If so check at the batt for around 13.6v+. These buses are set at 13.65 with the heat/AC blower on.

Even if the alt terminal output is correct it may not be getting to the batt so it is always best to check there.
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PD4107-152
PD4104-1274
Ash Flat, AR
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