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Onan 7.5DKDFL - A good fit for me?


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  #1  
Old 02-19-2016, 01:21:18 PM
DieselBound DieselBound is offline
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Default Onan 7.5DKDFL - A good fit for me?

Hi, folks!

First post. I've spent a little time researching on this unit and, thanks to the wealth of information here, I believe that I've got an opportunity to pick up a nice generator for my use/needs. I'd like to, however, get some feedback as well as ask a couple of questions. Please keep in mind that I'm not electrically literate.

So, here's the nameplate off the generator that I'm looking to pick up:



I've got a great appreciation for Kubota engines, having one in a tractor. I have several diesels, and am currently setting up to have some bulk diesel on the premises, in which case having a diesel generator fits well.

The generator has 659 hours on it and was government owned (no idea how the seller got a hold of it). Fairly confident that I could assess the functionality of the diesel engine: I have a compression tester, but am not sure I would be allowed to test the compression- generally if the thing starts well cold and runs smoothly the compression should be good; I can check oil and coolant for health there.

A generator would be for backup for home power, though if there's a way that I can leverage it for other uses then that would be a plus. Home power is pretty much a 1/2hp 240v well pump and several freezers (all chest, with a couple in and out of use and one serving as a chiller). Added in would be some power for electric fences and a couple of laptops (on UPSes, so power is stabilized there). Water heater is electric and would have to be switched off in the main breaker. My current electricity bill is estimated to be about 15KWH per day: we're not exactly scrimping, in which case we could readily cut back during the loss of main power. Heat is via wood. Propane stove: I'd contemplated a propane generator but diesel is cheaper.

I am planning on connecting to the home panel via an interlock. So...

I've read various comments about the power output for these units and it's not quite clear to me what amperage the wiring hook-up would need to support (and the required breaker sizing). I see that it lists 1ph and 3ph. I'd be wanting 1ph, which, if I'm reading the nameplate correctly, appears to show 31 per 120v leg: no idea how this translates to needed wiring for connection. I believe that I'd be looking to pull all power as 2 120v conductors? And, of course, there's the grounding issue- would I be confident that a good electrician would be able to deal with this properly? (I will only do wiring on outbuildings, not on anything connected to the house.) The generator is currently outfitted thusly:



If I were to make this more utilitarian I could see a need to retain that configuration, perhaps doing so via a cut-over switch (between it and the output to the main house panel)? I wouldn't want this to cause conflicts with the main purpose of providing backup power to the house and such, so it's not an essential function: just always look to leverage things as much as is sanely possible. Thoughts on just having this skid/pallet mounted and plucking it up with forks if I have to take it to use elsewhere? (I've got a few acres with various buildings and having some power to use like that would be nice for project work.)

Does it sounds like this unit would deliver the needed power? Does it seem like it would fit my "bill?"

Now, this all ASSUMES that the generator that I'm eying is actually what it's claimed to be. It's several hours away from me; if I go there I'm pretty much committing to buying it: OK, I don't HAVE to, but I intend to- make sure I get honest answers from the seller before I go there. As I understand it I should be able to take my electrical meter (Fluke 29) and check voltages and HZ with the generator under a full load. I've got a cheapo clamp meter, perhaps it has utility here? Not sure if the seller has a way to put a good load on the generator; would I look to haul a bunch of electrical stuff like the wife's hairdryer to plug in, or is there an easier/simpler way?

The asking price is likely on the high side (everyone would like a great deal!), but it's easily 1/2 what a new unit would be. I'm always prepared to pay fair price for something that I need (given it meets my expectations).

The unit appears to be pretty darn clean, considering that it's 25 years old.

Here is one side view of the whole unit:



Well, so much for getting pictures to pull in! (I may be electrically illiterate, but I'm not computer illiterate!)

So, here are some words that the pictures should have communicated:

[link: https://www.dropbox.com/s/zr2hg6egjm...nameplate.jpg]
Nameplate
Model number - 7.5DKDFL
Serial number - K910433098
Spec - 29418C

[link: https://www.dropbox.com/s/jpbh7zf5t5...eroutlets.jpg]
Power outlets (split in to two banks)
One 240v plug
Four 120v plugs

[link: https://www.dropbox.com/s/8j7921olo1...FLoneside.jpg]
Image of side of unit
Picture of the genset shows a clean engine, no visible oil stains, enclosed in a compartment (but open on the sides- not sure if there are sides with it; they're just not on in the pictures); there appears to be minimal rust toward the lower curved part of the generator head's casing
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Old 02-19-2016, 02:37:20 PM
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BigBlockChev BigBlockChev is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Hi and welcome to the forum. The DKD is my favorite Onan they are great generators reliable and versatile. 659 Hrs is quite low. In my market I would expect to get $3500 CDN for that gen. Your pics do not come through , try the "manage attachments" button below the reply box , be sure to keep the size down to below about 1MB so they will upload properly. Cheers Dan
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Old 02-19-2016, 02:44:12 PM
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Billy J Shafer Billy J Shafer is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

The DKD is an ok unit. I had one that we had to put a water pump on at 8000 hours so beware.

The DKD is a very good unit. Had 7 in a movie company. 24/7 for days with no problems. Just the normal stuff. Oil and filter change keep them clean.Had one that quit at twenty thousand hours. 659 is not even broken in yet.
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Old 02-19-2016, 02:44:54 PM
Radarman Radarman is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Welcome to the site!

looking at the tag, I can see it is an extended stack unit with option code B150 which means it puts full output in either single of 3 phase. that is a definite plus. looking at the unit, i believe you have a very nice, clean unit so the odds are looking better that it has been well maintained.

regarding load testing, gather up all the small electric heaters you can to test this. They usually have HI/LO settings that pull 1500/900 watts respectively. just plug in 4 and that will provide a 6K load which is plenty to see if this is producing sufficiently. To test the Hz, make sure you have a meter that can measure that, as most multi meters will NOT. Many folks around here suggest a KillaWatt meter which will definitely measure frequency, and they sell them at Lowes/HomeDepot.

http://www.homedepot.com/p/Kill-A-Wa...4400/202196386

In my opinion, something is only worth what someone is willing to pay. If this unit meets your needs, and you are comfortable with the price, then you have a good deal on your hands. Seems to me, a trip to see it in person would be the only way to confirm if this is what you are looking for.

Good luck!
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Old 02-19-2016, 05:29:20 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by BigBlockChev View Post
In my market I would expect to get $3500 CDN for that gen. Your pics do not come through , try the "manage attachments" button below the reply box , be sure to keep the size down to below about 1MB so they will upload properly. Cheers Dan
Dan, that's about right on with what the price is (adjusted for USD of course). Pretty much figure that it's a fair price; not a steal, but then again I don't expect to get a steal every time I open up my wallet

And everyone else, thanks for the input/validation.

Going back to one of my key questions, though, can I perhaps have a cut-over switch to output full power on two 120v legs to feed my main panel (while still allowing me to switch back for some other 120/240 uses as it's currently outfitted)?

And, can I get by with an 8ga line to connect to the main panel? I'm something like 25' (max) to the panel from where the genset is going to reside. Would 30amp breakers on each leg, at the generator and at the panel (for the interlock), be sufficient? (I seem to read that the genset is able to burst a bit beyond 60 amps)

Here's another shot to attach the actual pics (much easier than trying to use links!):
Attached Thumbnails
Click image for larger version

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ID:	246934   Click image for larger version

Name:	7.5DKDFLpoweroutlets.jpg
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ID:	246936   Click image for larger version

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Old 02-19-2016, 06:30:26 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Yup, have a meter that can read Hz. Also have a Kill-a-Watt around somewhere (quick and easy).

Will arm myself with hairdryers and stuff! (of course, if you saw me running around with a hairdryer I'd certainly look like a fish out of water!)
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Old 02-19-2016, 07:20:42 PM
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by DieselBound View Post
Going back to one of my key questions, though, can I perhaps have a cut-over switch to output full power on two 120v legs to feed my main panel (while still allowing me to switch back for some other 120/240 uses as it's currently outfitted)?
My 7.5 is wired with 110/240 output. The generator basically puts out two 110v legs going through two 30A breakers (2 x 3500w, 7000w total). I then wired each leg to a pair of 110v plugs AND in parallel, a single 220v twistlock plug. Since the breakers are before any loads, if I pull too much on either the 110 or 220, or any combination therof, it will throw the breaker. This way you can run both a 220 and 110 load and remain fully protected. So no, you should not need any sort of cutover switch UNLESS you need full output on a SINGLE 120 circuit (~65A).
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Old 02-19-2016, 08:04:23 PM
DieselBound DieselBound is offline
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Default Re: Onan 7.5DKDFL - A good fit for me?

Are you saying that you can pull full load through the 240v twistlock?

Based on the unit I'm showing here does it look like that 240v outlet can also provide full power, or will I be needing to alter something there? (I'd look to change it over to a twistlock).

I think that I'll better understand things when I can actually see it (sometimes I do better with visuals).

BTW - I'm hanging out waiting for a call from a seller of a 150 gallon fuel tank. This is all part of the Big Plan
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Old 02-19-2016, 08:52:35 PM
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Default Re: Onan 7.5DKDFL - A good fit for me?

Quote:
Originally Posted by DieselBound View Post
Are you saying that you can pull full load through the 240v twistlock?

Based on the unit I'm showing here does it look like that 240v outlet can also provide full power, or will I be needing to alter something there? (I'd look to change it over to a twistlock).

I think that I'll better understand things when I can actually see it (sometimes I do better with visuals).

BTW - I'm hanging out waiting for a call from a seller of a 150 gallon fuel tank. This is all part of the Big Plan
Welcome to the Stak. Can't beat a Kubota diesel on my opinion. Very thrifty fuel wise. Keep GOOD anti freeze in it.
I am running a 4 blade, 50 amp twist lock on my 7.5JB.
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Old 02-21-2016, 08:32:02 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
I am running a 4 blade, 50 amp twist lock on my 7.5JB.
Four blade?

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

https://seattle.craigslist.org/sno/rvs/5438136465.html
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