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  • #1

    6.5 kw generator question

    Not an emergency. Still have power. But today was the day to exercise the generator, and I decided to test the upper limits of the generator.

    It is rated at 6.5 kw. It has 2 duplex 120V receptacles, and a four prong 220V outlet. It also has a set of 8 amp 12v posts, which I have never used.

    It appears that no matter how I plug in the electric heaters, when I plug the third one in, the breakers trip.

    I have tried it through the duplex receptacles, and I have tried it through the 4 prong 220V outlet/cord.

    No dice, when I plug the 3rd heater in, it trips the breaker. I'll try to post a picture of the power panel:



    This is an air cooled diesel generator. Like so:

    Error Page | eBay
    http://www.ebay.com/itm/Aurora-6500DE-Diesel-Generator-Nothing-Else-Compares-/150578530533?pt=BI_Generators&hash=item230f2e08e5



    The engine does not appear to strain when I plug in the third heater, just the breakers trip.


    each heater used 11-12 amps at 120 v or ~ 1300 watts.


    thanks in advance,

    doug
    Tags: None
  • #2
    trips what breaker ? the main? how many are there and what are they rated ?

    is your Rotella mineral or synthetic (just kidding)

    Comment

    • #3
      Ok lets look at the thundering-ly obvious first:

      1) Are the heaters themselves good? Is it one particular one that causes the trip?

      2) Likewise, are all the outlets good?

      3) What is the condition of your connecting cable?

      4) Is the breaker itself ok?

      5) Maybe stage the heater startups. First do one... let it come up to full. Then the next. Let that one come up to full. Finally patch in the third. Could be your initial draw is causing the breaker to object.

      6) Check the venting on your gas-cap -- *runs like hell*

      Comment

      • #4
        Start with the fact that it is NOT a 6500W generator.

        It is a 5000 W generator, read the specs..... 5000W is the continuous output rating. 6500W is a "peak" rating.

        The 5000W is 20.8A at 240VAC....if you put two 12A heaters on the unit, that is 1440W per each, or 2880W. The third one then adds another 1440W, to only 4320W.... seems fine, right?

        But since the 120V breakers are set for 20A, and one of them is going to get 24A, it is no surprise they will open.

        If you want to put 12A heater #3 on it, you are going to have to run it from 240V with a 240V : 120V transformer, something like a standard "4-way" transformer.
        Last edited by J Tiers; 01-05-2014, 06:51 PM.
        CNC machines only go through the motions.

        Ideas expressed may be mine, or from anyone else in the universe.
        Not responsible for clerical errors. Or those made by lay people either.
        Number formats and units may be chosen at random depending on what day it is.
        I reserve the right to use a number system with any integer base without prior notice.
        Generalizations are understood to be "often" true, but not true in every case.

        Comment

        • #5
          Originally posted by J Tiers View Post
          Start with the fact that it is NOT a 6500W generator.

          It is a 5000 W generator, read the specs..... 5000W is the continuous output rating. 6500W is a "peak" rating.

          The 5000W is 20.8A at 240VAC....if you put two 12A heaters on the unit, that is 1440W per each, or 2880W. The third one then adds another 1440W, to only 4320W.... seems fine, right?

          But since the 120V breakers are set for 20A, and one of them is going to get 24A, it is no surprise they will open.

          If you want to put 12A heater #3 on it, you are going to have to run it from 240V with a 240V : 120V transformer, something like a standard "4-way" transformer.

          No you're WRONG -- it's the GAS CAP.

          Ok ok ok moving along now.

          Comment

          • #6
            The picture only a shows a single double pole breaker. With the genset rated at 6.5kva that should be a 30a breaker. Three 110vac heaters of 10-11a each would draw 30-33a, which would be at or above the breaker's rating for either side of the 220 output of the generator. You should be able to run two heaters on either leg (~4kw) of the 220 output with no problem.

            Comment

            • #7
              Like a fuse in a car just put a bigger breaker in!
              Andy

              Comment

              • #8
                Originally posted by jlevie View Post
                The picture only a shows a single double pole breaker.
                Good for you if you can make that out, is it upper right hand corner?


                no Andy - never the time to just "pop a penny in" or in the case of a car use a gum wrapper lol

                Comment

                • #9
                  The breaker on the generator power panel. That's what trips.

                  The heaters all check out fine on grid power. A clamp amp confirms that they draw 11-12 amps once started up. Their initial starting amps can be 15+ amps.

                  I plug them in one at a time.

                  All connecting cables are virtually new and known good and proper gauge for the amps.

                  Yes, the 6.5 kw rating of the generator is the peak watts, not the run watts.


                  The breaker (on the generator power panel) does not trip immediately, but after a minute or so.

                  This may very well be a problem of a few too many amps on one leg.

                  I'll have to hunt around for a few smaller loads, so I can get closer to the 20 amps per leg to test the top output.


                  thanks for the comments.


                  doug
                  Last edited by michigan doug; 01-05-2014, 07:23 PM.

                  Comment

                  • #10
                    Eh....

                    240V x 30 = 7200W..... nowhere do they claim that.

                    If in fact they are UL, as they state all over the linked advert, then they will NOT have a 30A breaker on a 15A 120V outlet..... yeah, I know, they are re-rated 20A if they have the extra option slot on the outlet..... but the max for them is still 20A...

                    120 x 2 x 20 = 4800W add a hundred watts for the 12V outlet (8.3 x 12 = 99.6) and you are about there.

                    The problem is that while you are below the WATTAGE rating, you are ABOVE THE CURRENT RATING....

                    Thank you, pull ahead please......
                    CNC machines only go through the motions.

                    Ideas expressed may be mine, or from anyone else in the universe.
                    Not responsible for clerical errors. Or those made by lay people either.
                    Number formats and units may be chosen at random depending on what day it is.
                    I reserve the right to use a number system with any integer base without prior notice.
                    Generalizations are understood to be "often" true, but not true in every case.

                    Comment

                    • #11
                      Originally posted by J Tiers View Post

                      Thank you, pull ahead please......

                      Why don't you just shout out --- NEXT! like the soup Nazi... ?

                      Comment

                      • #12
                        Originally posted by michigan doug View Post
                        Yes, the 6.5 kw rating of the generator is the peak watts, not the run watts.
                        In that case the genset is no more than 5kva (quite possibly 4.5kva continuous) and the rating is what it can momentarily supply for motor starting. Which in turn means that it will probably have a 20a breaker.

                        Comment

                        • #13
                          Yep, and the 20A breakers are rated LESS than the draw of the two heaters. How fast they open will depend on their operating time-current curve, and on how MUCH over 20A the two heaters are.

                          Originally posted by A.K. Boomer View Post
                          Why don't you just shout out --- NEXT! like the soup Nazi... ?
                          Because I am not in any way knowing what is this "soup Nazi" you mention.
                          CNC machines only go through the motions.

                          Ideas expressed may be mine, or from anyone else in the universe.
                          Not responsible for clerical errors. Or those made by lay people either.
                          Number formats and units may be chosen at random depending on what day it is.
                          I reserve the right to use a number system with any integer base without prior notice.
                          Generalizations are understood to be "often" true, but not true in every case.

                          Comment

                          • #14
                            each leg can carry 20 amps right?

                            And each electric heater only draws 10-11 amps. So the gennie will run two heaters all day long, but a third one slightly exceeds the 20 breaker on that leg and off she goes.

                            doug

                            Comment

                            • #15

                              Because I am not in any way knowing what is this "soup Nazi" you mention.
                              you might be sorry you asked - then again...

                              Seinfeld SOUP NAZI best bits.
                              http://www.youtube.com/watch?v=uVqBzP0xdKk
                              I want some soup!!!

                              Comment

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