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Onan 7.5DKDFL - A good fit for me?


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  #21  
Old 02-22-2016, 11:36:07 AM
Viking66 Viking66 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

I use the L14-30 on all of my Gensets.

Look on ebay and you will find them for great prices.
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  #22  
Old 02-22-2016, 01:14:24 PM
Radarman Radarman is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by Isaac-1 View Post
That is commonly called a 50 amp 120/240V Twistlock California connector (they are used on construction site power distribution boxes, I added one to my 10KW MEP-003) it would work but is probably overkill for what you need given the generator will only output just over 30 amps at 120/240V, You might be better off, putting a 30 amp output breaker on the generator and potentially lossing that 1 amp of output, and using a more common L14-30 connector commonly used on a 30 amp 120/240V generator inlet box, this is the same 4 prong plug found on 6KW 3600 rpm portable generators, smaller generators use the 20 amp L-14-20, or 120V only models often have the 3 prong L15-30 connector.

The common 30 amp RV connector is a 120V only 3 prog non twist lock, although there is a movement to go to L-15-30's for twist lock on 30 amp RV and the above mentioned California connector for 120/240V RV 50 amp cords.

Ike

ps that is a good price on the 50 amp RVcord if it is in good shape (retail is about $275 online), the other white one is a marine 30 amps 120V only 3 wire
Yep, this is what I have configured as well. I run a 30A breaker with L14-30 plug.

about that cable, you can also just replace the plug ends. the copper wire part of the cable is what you are paying for, not the plugs.
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  #23  
Old 02-22-2016, 01:58:52 PM
Isaac-1 Isaac-1 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

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Originally Posted by Radarman View Post
Yep, this is what I have configured as well. I run a 30A breaker with L14-30 plug.

about that cable, you can also just replace the plug ends. the copper wire part of the cable is what you are paying for, not the plugs.
I don't know about that, those 50 amp California connectors are not cheap ($35-$40 per end on amazon) vs about $12 for L-14-30's
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  #24  
Old 02-22-2016, 03:06:22 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

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Originally Posted by Isaac-1 View Post
I don't know about that, those 50 amp California connectors are not cheap ($35-$40 per end on amazon) vs about $12 for L-14-30's
Yes, that is what I was seeing too. And then there's the cost of the receptacles too: I'd be looking to rewire on the generator side as well as the receptacle feeding the main panel.

Consulting here with everyone has likely saved be a couple hundred bucks!
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  #25  
Old 02-23-2016, 11:58:52 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

OK, I picked the unit up. Everything seemed to pan out. I loaded it up and the Hz was 60 to 61. It was barely noticeable when running 2 1500 watt heaters, a 1875 watt hair dryer and as orbital sander (power draw unknown- didn't have it loaded against anything, but it was instructive to at least have a draw from the start up of an electrical motor).

The oil and coolant look like it was just changed, but the seller did not change them: the oil is still honey colored! (there's a note on it to use 15-40w). Oil filter is dated 2008, it was likely taken out of service not long after this. I need to test the coolant. There's two fuel filters.

The unit has a 35 amp main breaker. In the additional box it's got 4 slim 20 amp breakers with the middle two breakers tied. Haven't tried switching these breakers to see which controls which.

Here's a picture of the auxiliary breaker panel:
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  #26  
Old 02-24-2016, 12:17:49 AM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Here's a video of it starting and running. It was just above freezing this morning.

https://www.dropbox.com/s/dzdjsh3mnismb0x/Startup.MOV

When I saw it start up at the seller's (also cooler there) it basically did the same thing: seemed to fire up right away and then stop, with a second crank taking hold.
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  #27  
Old 02-24-2016, 09:02:09 AM
PopsGarage PopsGarage is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Nice !!!!!
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  #28  
Old 02-24-2016, 09:07:48 AM
Isaac-1 Isaac-1 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Looks good, but something is off with the way those breakers are tied together we may need more details and see what is going on under the panel covers. What do the outlets look like?
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  #29  
Old 02-24-2016, 11:20:53 AM
Radarman Radarman is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by DieselBound View Post
When I saw it start up at the seller's (also cooler there) it basically did the same thing: seemed to fire up right away and then stop, with a second crank taking hold.
In my experience, this is due to the oil pressure not having time to build up sufficiently so the oil pressure sensor shuts the engine down. At least this is what I believe it to be on my JC and JB as they both do the same thing. If I hold the start button down just a bit after the engine starts, it stays running.
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  #30  
Old 02-24-2016, 11:41:04 AM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by Isaac-1 View Post
Looks good, but something is off with the way those breakers are tied together we may need more details and see what is going on under the panel covers. What do the outlets look like?
Yeah, seems odd to me too. I'll look to pop off the cover on that panel and see how it's wired. I don't think that it's likely to be a screw-up , as this wasn't done by a backyard hack (like me).

Does that 35 amp main breaker seem right, is it stock?

Quote:
Originally Posted by Radarman View Post
In my experience, this is due to the oil pressure not having time to build up sufficiently so the oil pressure sensor shuts the engine down. At least this is what I believe it to be on my JC and JB as they both do the same thing. If I hold the start button down just a bit after the engine starts, it stays running.
Yes, that sounds exactly like what's happening. On the second crank I held down the starter a bit longer; I might look to do this on the first crank the next time I fire it off to see if it'll catch and stay. NOTE: it's a new battery (seller purchased it); he'd had it connected on another pieces of equipment; I read it as 12.4v before hooking it back on this unit; as can be seen in the video the alternator is putting out fine.

One other interesting thing with this unit is that we'd had it running for some time and the temperature barely came up. I'm wondering whether the thermostat is stuck open, the gauge isn't functioning correctly or whether this is just how the engine is.
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  #31  
Old 02-24-2016, 12:17:34 PM
Radarman Radarman is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

There was a recent discussion regarding temperature around here. In general, temp is pretty important and should get hot enough that the moisture in the oil has a chance to evaporate which means an oil temp of 212 or so degrees. Since oil usually runs ~30-40 degrees hotter than the coolant, I would say you should make sure the engine coolant heats to at least 180 or 190.
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  #32  
Old 02-24-2016, 12:24:31 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by Radarman View Post
There was a recent discussion regarding temperature around here. In general, temp is pretty important and should get hot enough that the moisture in the oil has a chance to evaporate which means an oil temp of 212 or so degrees. Since oil usually runs ~30-40 degrees hotter than the coolant, I would say you should make sure the engine coolant heats to at least 180 or 190.
Yes, I'm going to measure the temp to rule in/out the thermostat.
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  #33  
Old 02-24-2016, 12:57:10 PM
Radarman Radarman is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Yep.. I am still a bit shaken when I discovered that my boat thermostat destroyed itself and was running full open last season. I just thought the temp gauge was bad and reading low. I was running the engine pretty hard the last time I was out. Had it wrapped up to 4500-5000 rpm and I bet the engine was only 140-150 max.



Dont be me.
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  #34  
Old 02-24-2016, 01:21:25 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

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Originally Posted by Radarman View Post
Yep.. I am still a bit shaken when I discovered that my boat thermostat destroyed itself and was running full open last season. I just thought the temp gauge was bad and reading low. I was running the engine pretty hard the last time I was out. Had it wrapped up to 4500-5000 rpm and I bet the engine was only 140-150 max.



Dont be me.
I've never had a problem with my Kubota tractor; actually, it's usually the opposite because I have to keep cleaning the radiator screen. And speaking of radiator blockages, the seller of my generator had this 2-cylinder Kubota from a refrigerator truck that he hooked up to a water pump that would run all day long. His wife was out checking their cattle and discovered that the fan belt on the engine was melting down (or some other ugly sight). The radiator neck and cap got blown off. Apparently one of his kids did some mowing and kicked a bunch of crap into the radiator. Anyway, he checked things over and found that the engine hadn't seized. He ended up firing it back up and it's been working fine since. Kubota engines are hard to kill!

Running at only 1800 rpm (and flowing a pretty good amount of air) it's a bit trickier to get these things warmed up. Not good to have a cold diesel (any engine really). I'm pondering whether I want to make some side panels, mainly for protection from the elements, but wonder whether how this will affect the running temp. Cooler part of the year is when this thing is most likely to see action: may get down into the mid to higher teens, though that's infrequent (mid twenties is more common).
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  #35  
Old 02-25-2016, 04:22:25 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

I'm going to go ahead and order up some stuff to connect the generator up to my main breaker panel (via interlock- http://www.ebay.com/itm/221368654965). Not sure if I'll need to rewire the 240v outlet on the generator or not, but I know that I'll need a locking receptacle; so... will this one be good to go with?

http://www.ebay.com/itm/131589664804

On my main house panel side I'll be going with this:

http://www.ebay.com/itm/371435705555

I'll use this cord to connect with:

http://www.ebay.com/itm/261237252632

Not promoting or endorsing any of these items, they're just what I figured would work for me.
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  #36  
Old 02-25-2016, 05:05:26 PM
Isaac-1 Isaac-1 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Looks like a good plan
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  #37  
Old 02-25-2016, 10:58:34 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Attaching a picture of what I found when opening up the add-on breaker panel. The tied middle 20 amp breaker supplies the 240v outlet.

I'd like to have a full 30 amp available to the 240v outlet and still have a 120v outlet. Not really sure yet. Likely have to change that panel to achieve that. The wires to the outlets seem to be 12 ga. Would that still support a 30 amp 240v outlet? (12 ga = 16 amps; times 2 wires = 32 amps for 240v?)
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  #38  
Old 02-26-2016, 01:36:19 AM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Yikes! Never mind on the question about wiring the 240v for 30 amp, that should be 10 ga minimum!
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  #39  
Old 02-26-2016, 02:43:37 AM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

You need to post a few pictures of the output wires coming off the generator end. they should be bigger than #12. Run new wires connected to the gen. output wires to the aftermarket breaker box you have a picture of.

My 7.5 DKD has a ganged pair of 35 Amp. breakers mounted in the control box that I believe are factory installed. You can see the breaker on the left side of the control box under the voltage regulaton transformer on post # 29


http://www.smokstak.com/forum/showth...=140411&page=2
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  #40  
Old 02-26-2016, 11:53:45 AM
Radarman Radarman is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

I would think 35A breakers are just fine. that means you will throw the breaker at 8400 watts which is probably just fine. I have seen a few 7500 watt generators with 35A breakers. 30A breakers will allow 7200 watts which is a bit under your max. Since these generators are so overbuilt, pulling a few extra amps will likely not hurt a thing. I am thinking of upgrading my 30's to 35's on my 7500JB.

Here is how I wired my set providing single phase 120 and 240. I ran a dual throw 30A breaker as the main with both hots running through this. I then ran from the 30A main breaker directly to the L14-30 plug providing 30A 240v. I also went from the 30A main breaker to another small box with two additional 20A breakers and two 120v plugs. This way, ALL power runs through the 30A main breakers, and I also run 20A breaker for the 120v. I can use either 120 OR 240, and will not overload the generator.
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