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Generator not charging

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mbigpops
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Generator not charging

Post by mbigpops » Wed Aug 10, 2016 12:45 pm

I am still not seeing anything on my ammeter showing that my generator is charging. I have the three brush generator with the cutout relay on my KL. I have the one wire coming out of the generator to the lower screw on the relay and then one wire from the top of the relay going over to the ammeter.

I originally thought that maybe the third brush needed to be re-located so I removed the band from the generator and was able to easily slide what I am assuming is the third brush about an inch forward (towards the flywheel). After that I ran the engine up to 1500 RPMs and saw my DMM run up to 13.5 volts temporarily but still nothing on the ammeter.

I went out for a lake run a couple days ago and hooked the DMM to the cutout relay terminal and ground and it read 12.41 VDC (battery voltage level) at idle and never went above that up through 2000 RPMs.

I contacted my generator restorer who said that it did not need to be flashed and that I could bring it to him to get re-tested but I don't want to take it out now.

Are there any other tests that I can perform to more accurately determine that it is not something simple before I go removing the generator ?

Thanks

Mark
1953 CC Rocket Runabout "Rocket Man"

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Bilge Rat
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Re: Generator not charging

Post by Bilge Rat » Wed Aug 10, 2016 1:51 pm

Are you certain the ammeter is good? 13.5 volts on your multi-meter would seem like it's charging. If your multi-meter can handle and read at least 10 amps constant and say 20 amps intermittently, you could connect it in place of the existing ammeter and see if any charging current is flowing. I wouldn't run it on the multi-meter for long as charging currents would probably exceed what the meter leads or internal fuse could handle. For larger currents, you would need a meter shunt. While an ammeter is a very simple gauge, it still could be bad.

In lieu of that, you could temporarily hook up a connection between the battery positive, the "input" side of the ammeter, the "output" side of the ammeter and some sort of load like a bilge pump. Then the other side of the load to battery negative. The ammeter should show current flow.
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1953 Chris Craft Sportsman 22 foot "Summerwind"

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mbigpops
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Re: Generator not charging

Post by mbigpops » Wed Aug 10, 2016 6:56 pm

The ammeter is working properly. Before I installed the engine I ran my electrical items (blower, lights, etc.) off of a DC Power Supply and through the ammeter. It always displayed correct amperage for each item. It also deflects slightly negative when I first turn the key to on which I understand is normal.
1953 CC Rocket Runabout "Rocket Man"

Denis D
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Re: Generator not charging

Post by Denis D » Wed Aug 10, 2016 9:19 pm

Mark,

Knowing the craftsmanship you put into this project, I suspect you are starting out with a fully charged battery. If that's the case the battery may not draw very much current so the meter probably won't deflect positive very much if at all. At least that's the case with voltage regulator circuits, I don't have a lot of experience with the cutout circuits so I am not positive they act the same.

The best indication would be to put your DMM directly on the battery and check the voltage with the ignition on and engine off which should be over 12 volts. then with the engine idling, it should drop slightly. Keep your meter on it as you run around the lake for a while and see if the battery voltage increases, stays the same or drops which will tell you if the generator is indeed maintaining the battery. You can turn your nav lights on while running to increase the load which should shorten the time it takes to evaluate it. Battery voltage is the best indication which is why newer cars use battery meters instead of amp gauges.

Good luck,

Denis D
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mbigpops
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Re: Generator not charging

Post by mbigpops » Thu Aug 11, 2016 7:47 am

Denis,

Yes I have a brand new battery that is fully charged. It measured 12.5 VDC before running last time out and while running was measuring the 12.4 VDC the whole time. It was last charged about 2 months ago.

I took it out of the boat last night and charged it again as the manufacturer recommends that the voltage not go below 12.6 VDC. I am assuming that if my generator was working properly I should never have to charge the battery during summer usage and the generator should take care of that.

I still am wondering whether I should move the third brush again and in which direction, check the field wire coming out of the generator or what before just assuming that the generator is not working.

Mark
1953 CC Rocket Runabout "Rocket Man"

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drrot
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Re: Generator not charging

Post by drrot » Thu Aug 11, 2016 7:48 am

Mark,
Take a friend boating with you. Leave the motor box on the pier if needed. Loosen one battery cable. Go out and get the engine up to 2000 RPM. remove the battery cable being prepared to put it right back on. If the engine dies the generator is not charging. If it continues to run it is running on generator power.
Jim Staib
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1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

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mbigpops
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Re: Generator not charging

Post by mbigpops » Thu Aug 11, 2016 6:36 pm

So that is it. With all of the technology in the world all I get is the Jim Staib "Whiplash Test" ?

Jim - I don't have an engine cover to leave at the dock but I will be sure to wear an adult brief for the test run in case I leave something else somewhere.

Mark
1953 CC Rocket Runabout "Rocket Man"

Denis D
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Re: Generator not charging

Post by Denis D » Fri Aug 12, 2016 2:00 pm

Mark

From what I have learned researching the 3rd brush generators, they are constant current devices. That means whatever current output you adjust it to it will maintain no matter what the load or battery condition so you should see a positive ammeter deflection when the RPMs are sufficient.

It seems like the only option you have in the boat is to try adjusting the 3rd brush. From what I have read, the closer you move it to the fixed brush, the higher the current output.

Good luck and let us know what you find, I will be dealing with the same generator when I get that far :?

Denis D
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Re: Generator not charging

Post by evansjw44 » Sat Aug 13, 2016 8:34 am

The at rest voltage of a 12 volt lead acid battery is 12.6 volts at 70 deg F. Its fully charged "float" voltage is 13.6. Nominal charging voltage is between 13.8 and 14.4 volts. Above 14.4 and you will overcharge the attery and eventually destroy it.
Jim Evans

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mbigpops
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Re: Generator not charging

Post by mbigpops » Sun Aug 14, 2016 11:18 am

I did a test today that I think found the problem. The old tractor forums are a wealth of information on generator issues.

After reading up on the subject I decided to test the cutoff relay thinking my generator restorer may have tested the generator but not the cutoff relay. I disconnected the wire coming out of the generator from the cutoff relay and also the wire from the cutoff relay to the ammeter (isolate the relay basically). I then hooked up a variable output DC power supply where the generator wire normally goes and a DMM to where the ammeter normally goes. I increased the voltage slowly from 0 VDC all the way up to 19 VDC and all I saw on the DMM was a fraction of the input voltage. At 14 VDC out the power supply I saw only 1.8 VDC at the DMM. The could hear the relay actuating at 10 VDC but the output voltage never went up.

Does this make sense as a internal failure of the cutoff relay ? Should I bring it back to my generator guy or look for a replacement ?

Thanks

Mark
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drrot
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Re: Generator not charging

Post by drrot » Sun Aug 14, 2016 1:07 pm

Mark,
Remove the generator belt. Run a jumper from one side of the cut-out to the other. If the generator spins like a motor it is working.
Jim Staib
www.finewoodboats.com


1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

Denis D
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Re: Generator not charging

Post by Denis D » Sun Aug 14, 2016 2:04 pm

That sure sounds like a bad cutout relay.
You can bypass the cutout with a jumper wire while the engine is running at higher RPMs and the ammeter should show positive current flow. That would pretty much prove a bad cutout.
When all is done, you I'll probably have to re-adjust the 3rd brush for the proper output current.

Denis D
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mbigpops
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Re: Generator not charging

Post by mbigpops » Wed Aug 17, 2016 7:56 pm

Yes it was the cutout relay.

Pretty nasty inside. Generator output is good and the ammeter needle went positive when I jumpered the relay out.

Cleaned up the relay and it actuates good now and the full voltage comes through after the click. Just have to put it back on the generator.

Thanks for the help.

Mark
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Re: Generator not charging

Post by jim g » Wed Aug 17, 2016 8:55 pm

Make sure when you turn the key off that the amp meter pops back to 0. If it pulls to the negative and stays there. Disconnect the battery immediately. If you can't disconnect it quickly then crank the engine back up.

With as crusty as that cut off box is. I would not trust it. If it sticks in the closed position it will turn the generator into a motor and since the belt won't let it turn it will melt the inside of the generator done.

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mbigpops
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Re: Generator not charging

Post by mbigpops » Mon Aug 22, 2016 6:39 am

That crud was mostly where you see it on top of the metal bar that pivots when the magnet engages. The source of the crud was from condensation and rust on the inside of the cover. I cleaned it up and sprayed some corrosion inhibitor inside the cover.

The relay cleaned up nicely and I have tried many cycles and it has never stuck closed and the retention spring is in good condition.

Went for a run yesterday and saw some life on the ammeter for the first time ever. At lower RPMs it read about +10 Amps and then went up to +20 Amps around 1500 RPMs and higher. Never went up to the "Charge" level (battery was fully charged).

Mark
1953 CC Rocket Runabout "Rocket Man"

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