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Onan 7.5DKDFL - A good fit for me?


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  #11  
Old 02-21-2016, 09:07:20 PM
Isaac-1 Isaac-1 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Those questions are a little bit confusing, it would help if you could tell us what you have and what you want to do.

Ike
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Old 02-21-2016, 10:23:27 PM
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by DieselBound View Post
Four blade?

Would this 50amp work? (only three blade?)

https://seattle.craigslist.org/sno/rvs/5438136465.html
My TWIST LOCK end looks like that. It has three prongs and that metal strip on the side is a ground. The PUSH IN plug end of my cord has 4 prongs like that used on an RV. I have the twist lock end hooked to a power inlet on my home. I needed the 4 prong with a right angle to fit inside a closed door cabinet.
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  #13  
Old 02-21-2016, 10:37:21 PM
Isaac-1 Isaac-1 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

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
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  #14  
Old 02-21-2016, 10:39:10 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by Motorhead View Post
My TWIST LOCK end looks like that. It has three prongs and that metal strip on the side is a ground. The PUSH IN plug end of my cord has 4 prongs like that used on an RV. I have the twist lock end hooked to a power inlet on my home. I needed the 4 prong with a right angle to fit inside a closed door cabinet.
Great! Looks like if this is only $90 then it's a steal!

NOTE: The reason why I'm delving into this issue is because I'm wanting to make sure that before I pull the trigger on spending $2,800 (plus a cord, plus an electrician's time, plus, likely, a new service box [mine looks like there's no interlock out there]) that it's all going to work. I've never done anything like this before.

NOTE II: Got the fuel tank that I was after. Though I won't be hooking directly to it it'll provide me with plenty to refill from to last me many days.
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Old 02-22-2016, 12:11:46 AM
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Default Re: Onan 7.5DKDFL - A good fit for me?

You can have any type of plug that you require installed on the generator or your cord, as long as it has the correct configuration and number and guage of wires to handle the load. Your DKD will put out 31A at 240V or 63A at 120V depending on how you want to configure it. See the chart below for plug types and ratings. Cheers Dan
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Old 02-22-2016, 12:58:38 AM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

OK, at roughly 30 amps that's full output at 240V. A 30 amp breaker, as Issac-1 states, is all that I'd require there.

Looking up the plugs for the 240V the chart (thanks!) seems to show that that's set up for 20 amps (see pictures above), it's a 6-20R. Is this correct?

Am I safe to assume/think that I could change the breaker on the generator (if it's not already 30 amp) to 30 amp and, if needed, change the wiring to the 240V outlet (along with with a 6-30R receptacle)?

If it's 30 amps then I need only obtain a cord rated for 30 amps? (how many wires?)

Regarding the generator...

I've gotten in touch with the seller (of the generator) and have arranged to take a look at it tomorrow: it's a 2hr drive each way. The unit was originally used in what sounds like a work truck (government) and was obtained by a school district which promptly removed it from the truck, after which it sat for several years (under cover) before the seller picked it up. Seller says that he had an electrician look at it and verified that it worked as should, though they didn't have anything to hook up to the 240V outlet- this doesn't matter, does it? It only matters that it can output at or near full output capacity? Any concern here? I don't have anything 204V that I can take to plug in. The seller says that electrician confirmed that the outlet had 240V on it. If the engine runs fine (esp with a load) and I'm not seeing any leaks (stuff gone bad/brittle from sitting- esp IP issues) can I feel pretty certain that it's all fine?

The seller was going to use it for backup but decided that he couldn't justify it based on the value of it. Apparently it's overkill for him. Might end up being that way for me, but looking at things now I feel comfortable with all of it (if I don't use it that much then fine- it's insurance, insurance that I figure I'll never have to shell out for again).
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Old 02-22-2016, 01:52:21 AM
nothingbutdarts nothingbutdarts is online now
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Default Re: Onan 7.5DKDFL - A good fit for me?

Not knowing but, guessing what's under the outlet covers of the main box in your post #5 above it looks like you have two 120V outlets to the right of the electrical panel and a 240v. outlet to the left side of the panel.

You will need a ganged pair of 30 amp. breakers, meaning two 30 amp. breakers that are connected at the trip switch of the breakers, so when running 240v. it will trip both breakers. This will be connected just coming out of the generator before the outlets. It already most likely is set up that way in the big box above the outlets.

Take with you a few hair blow dryers and a plug in space heater or two if you have some or can borrow some. Most blow dryers are about 1,500w so with two of them you have a 3,000 watt load already. Space heaters are usually between 1,000 and 1,500 watts each. It would be pretty easy to then come up with a 6,000w. load with all those. All of course would be plugged into the 120v. outlets. You don't need anything that runs on 240v. to see it put out close to rated output, just enough 120v. loads to make up something close to 6,000w. should give you a good idea if it's working OK.

If I were looking at it, I would like it to be completely cold when I got there to make sure it starts OK cold. It should have glow plugs that you preheat with before you actually crank the engine. My DKD does and you manually have to preheat them before trying to crank the engine over. Your's being newer, might do that process automatically. Not sure on that fact.
Most likely it will smoke for a few minutes after start up till it gets some heat built in the cylinders. Let it warm up for 5 minutes and then load it!
If you have a volt meter you might check battery voltage before even trying to start it and then battery voltage again after it has run for 10-15 minutes to make sure the battery charging circuit is working properly. It won't be a fast type charge like a car would be but a slower charge, it should climb maybe half to a full volt above what you measured before starting it.
See if the coolant in the radiator looks clean and clear and general condition of the unit, the belt and hoses.
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Old 02-22-2016, 02:23:09 AM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

nothingbutdarts, many thanks for the input!

Yes, two two outlet 120v outlets to the right and one 240v on the left.

I've got a several small electric heaters (came with my wife!). Might also look to take the wife's hairdryer.

Yes, cold starting. I recently went to look at a 4wd utility vehicle -diesel- and when I got there the guy had had it running for a while: he was honest in stating that he had a hard time starting it- battery dead and the glow plugs were questionable (I showed him how to test them); I had a compression tester with me and I discovered that one cylinder, of three, was down significantly- I didn't buy it. So, again, yes, and, thanks for the reminder! The seller says that it also comes with a block heater: someone jokingly asked him how he was going to use a bock heater when the power was out! (the joke was that he'd plug it in before the power went out) I know that my Kubota tractor is kind of pig-ish to start when it's cold, it does it, but it rattles, clanks and smokes quite a bit at first but then settles down and just runs sweetly.

And also, thanks for the note about checking the battery voltage before starting and to check the coolant.
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Old 02-22-2016, 03:05:47 AM
Isaac-1 Isaac-1 is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

That chart that BBC posted only shows the straight blade NEMA outlet option, it does not show their twist-lock cousins which usually have the same name with the letter L before it and curved blades. There are also some non NEMA outlets that are code legal in the US, such as the above mentioned 50 amp California twist lock connector. (which also has several similar looking cousins for other voltages, and 3 phase power) as well as the various pin and sleeve industrial connectors some of which are water tight. ( these at one point had a number of proprietary designs, but have now settlded around a color coded international standard)

As to your mention of the 6-20R this is a rather unusual outlet as it is 20 amp 240V only 3 wire (2 hots and a ground, no neutral, so therefore not 120/240V) and most likely is not something you would want to use for your application. About the only applicaiton that comes to mind where I have ever seen these were old Xerox photocopiers from the 1970's, and maybe some 240V window air conditioners.


As to the output breaker there is a good chance one is already included on the generator as they have been required by NEC code for a number of years, it may be the wrong size though if this generator had been connected with one of the 3 phase output options. Also most factory commercial / industrial generator output breakers will be of the industrial molded case variety and may be 2, or 3 pole breakers, not a pair of residential / light commercial style breakers with the the levers pinned together as nothingbutdarts describes.


Overall don't worry about type of cord you need, or other details like that we can get you sorted on those later. Also if you do try to run it with heaters connected and it is wired for 120/240V make sure you put a balanced load on it, not over 3.75 KW per L-N leg, we don't want you burning out the generator stator before you even buy it with too big of unbalanced load.


Ike
p.s. Ooops I just went back and looked at the photos that Square D brand box most likely does contain residential style breakers like nothingbutdarts described as it certainly is not factory
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Old 02-22-2016, 11:22:21 AM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Yes, thanks again. I believe that I've sorted out what cords and connectors (L14-30), but will wait until later to verify (look in the box- it was likely added/wired by the DOT).

Will report back on whether I get the generator or not.
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