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Old 17-10-2014, 12:25   #61
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Re: How Do You Use Your Generator?

Quote:
Originally Posted by Cadence View Post
Don't look for problems.
I really like that advice, especially with plenty of boat problems over the years that have come looking for me.

Just to clarify, as appliances are turned on my Hertz meter dips from 60 to progressively lower as the loads are increased, and the meter stays at that lower level so long as the appliances are left on. As they are turned off, the meter works itself back up to 60. I do get that momentary dip when a big start-up load such as an a/c is first turned on, but it's only momentary and I've never worried about that one.
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Old 17-10-2014, 13:29   #62
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Re: How Do You Use Your Generator?

Quote:
Originally Posted by Exile View Post
I really like that advice, especially with plenty of boat problems over the years that have come looking for me.

Just to clarify, as appliances are turned on my Hertz meter dips from 60 to progressively lower as the loads are increased, and the meter stays at that lower level so long as the appliances are left on. As they are turned off, the meter works itself back up to 60. I do get that momentary dip when a big start-up load such as an a/c is first turned on, but it's only momentary and I've never worried about that one.
I still don't think you should be overly concerned about 4 or 5 Hz. Most people have no idea about that. The governor was probably set static. Don't screw with it. You may do more harm than good. I could be full of BS. Don't sweat the little things. Hopefully someone more knowing more than I will chime in.
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Old 17-10-2014, 13:46   #63
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Re: How Do You Use Your Generator?

Quote:
Originally Posted by Cadence View Post
I still don't think you should be overly concerned about 4 or 5 Hz. Most people have no idea about that. The governor was probably set static. Don't screw with it. You may do more harm than good. I could be full of BS. Don't sweat the little things. Hopefully someone more knowing more than I will chime in.
I tend to agree with Cadence.

However, it is true that a permanent dip in frequency is different from a momentary sag.

It means the governor is really not working quite right. However, I agree with Cadence that it's not worth sweating relatively small stuff. This is relevant:

"Portable generators, not connected to a utility system, need not tightly regulate their frequency, because typical loads are insensitive to small frequency deviations."

Utility frequency - Wikipedia, the free encyclopedia


Have you checked your genset's specifications? My genset, a fairly high quality, heavy-duty, continuous-use rated unit, a Kohler 6.5 EFOZ, which produces very clean power, is allowed a 5% frequency deviation. That would be 3hz in your case. So it doesn't look like 3 or 4 herz is too much of a big deal.
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Old 17-10-2014, 13:53   #64
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Re: How Do You Use Your Generator?

When I lived in Germany, we took a lot of appliances with us, or course Germany is 50 Hz, US 60. Only thing that ran flaky was mechanical clocks, they ran slow. If you are worried about it, adjust your genny to run at 62 Hz unloaded, split the difference, that way when it sags 4 Hz, it's only 2 low
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Old 17-10-2014, 21:12   #65
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Re: How Do You Use Your Generator?

OK, if nothing else your advice & comments have motivated me to delve back into the electrical side of my genset's service manual, an area that has thus far had me pretty psyched out.

A few highlights:

1. The Hertz acceptable deviation range is listed from a high (no-load) of 61.5hz to a low of 58.5. So Dockhead, there's your 3hz or 5%. I routinely go below 58.5, but that's only assuming the meter on my elec. panel is accurate. I don't have any indp't. way of measuring Hz.

2. To accurately determine no-load frequency, a partial load must first be applied and then turned off. I've never done this so this is another potential variable that could be throwing things off.

3. There is a corresponding deviation range for voltage (108-128 or thereabouts) which I recall being within but will confirm when I get back to the boat.

4. Adjusting either the frequency or voltage via the governor sounds a bit tricky, involving adding/removing shims to the mechanical governor assembly, and moving wires around on the AC & Hz output panels (the locations for which I have no idea). As far as I can gather, the problem with simply increasing the engine rpm's is that it will do so across the board, i.e. from no-load to full-load & everywhere in b'twn. In my case, I'm pretty sure (but will confirm) that my no-load settings are probably OK, so I would need to increase the rpm's via the governor at various loads to accomplish corresponding increases in frequency and/or voltage.

5. While we all know that a little knowledge can be dangerous, slightly more than a little knowledge on my part could very well be fatal for my generator. I am therefore inclined to follow your sage advice to leave things be, taking comfort in knowing that there will soon be plenty of other boat issues waiting to confront me.

Thanks again for the help, and for a useful & relevant thread.

Dan
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Old 18-10-2014, 01:53   #66
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Re: How Do You Use Your Generator?

After crossing the Comax Bar, the plastic boater tracked down the fish boat he just followed across.

I want to thank you for your local knowledge, and leading me safely across the bar in all that fog!!!

Don't thank me....I figgered because you were following me in, at such close range, that I must be doing something right. I didn't even know there was a bar, this is my first time in Comax

Lloyd


Quote:
Originally Posted by Exile View Post
OK, if nothing else your advice & comments have motivated me to delve back into the electrical side of my genset's service manual, an area that has thus far had me pretty psyched out.

A few highlights:

1. The Hertz acceptable deviation range is listed from a high (no-load) of 61.5hz to a low of 58.5. So Dockhead, there's your 3hz or 5%. I routinely go below 58.5, but that's only assuming the meter on my elec. panel is accurate. I don't have any indp't. way of measuring Hz.

2. To accurately determine no-load frequency, a partial load must first be applied and then turned off. I've never done this so this is another potential variable that could be throwing things off.

3. There is a corresponding deviation range for voltage (108-128 or thereabouts) which I recall being within but will confirm when I get back to the boat.

4. Adjusting either the frequency or voltage via the governor sounds a bit tricky, involving adding/removing shims to the mechanical governor assembly, and moving wires around on the AC & Hz output panels (the locations for which I have no idea). As far as I can gather, the problem with simply increasing the engine rpm's is that it will do so across the board, i.e. from no-load to full-load & everywhere in b'twn. In my case, I'm pretty sure (but will confirm) that my no-load settings are probably OK, so I would need to increase the rpm's via the governor at various loads to accomplish corresponding increases in frequency and/or voltage.

5. While we all know that a little knowledge can be dangerous, slightly more than a little knowledge on my part could very well be fatal for my generator. I am therefore inclined to follow your sage advice to leave things be, taking comfort in knowing that there will soon be plenty of other boat issues waiting to confront me.

Thanks again for the help, and for a useful & relevant thread.

Dan
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Old 18-10-2014, 02:17   #67
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Re: How Do You Use Your Generator?

Today with binoculars is the first time to see the range markers' flashing lights for directing across the bar, and it is the first time we have come this




Quote:
Originally Posted by FlyingCloud1937 View Post
After crossing the Comax Bar, the plastic boater tracked down the fish boat he just followed across.

I want to thank you for your local knowledge, and leading me safely across the bar in all that fog!!!

Don't thank me....I figgered because you were following me in, at such close range, that I must be doing something right. I didn't even know there was a bar, this is my first time in Comax

Lloyd
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Old 21-10-2014, 17:14   #68
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Re: How Do You Use Your Generator?

Quote:
Originally Posted by Exile View Post
As for your question about how to determine the load on your generator, I've always wondered the same thing and just asked in the previous post whether this might be determined (albeit imprecisely) via the Hertz meter.

As for how the batteries get charged, the generator produces 110v (probably 240v on Dockhead's) of AC power which supplies a battery charger which also runs on 110v. This charges the batteries and other AC appliances just like being plugged into shore power. Not sure about others, but my genset also has its own 50A alternator which, via its regulator/rectifier, supplies DC power directly to its own start battery.

As to whether the engine alternator or the battery charger would charge your batteries faster, the simple answer depends on the output of each one. The better question might be which one can do it more efficiently. In my case and I would think for most, the genset will burn much less fuel/hour than a propulsion engine and so is the obvious choice when under sail or at anchor/mooring, especially if there are benefits to running other AC appliances (e.g. refrig, watermaker, a/c, heater, stove/oven) while you are also charging your batteries.

Dan
Thank you Dan and all the others who posted ... now I get it - I now have a much clearer understanding.
Chris
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