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Author Topic: Powertech gen set - no go - Clifford was right  (Read 1270 times)
chuckd
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« on: July 08, 2013, 02:17:52 PM »

Two years ago, I had a gen set fire, replaced the Perkins/Kohler 12.5 with a 8kw Powertech gen set.  Neat install etc, now I do not use the bus air going down the road, as I live in Mn, and normally stay north not stray south.  But this year, in a couple of weeks was going to venture down to Santa Fe, to take in the sites, see the Opera (not my idea) etc.  So need the cruise airs.  They (it will not start) with the powertech, loads down and sparks fl  .  Now two years ago Cliffiord said:  "8kw powertechs will not start a cruise air".  Why I did not ask before the install is a question I am still pondering.  We have tried, various voltage regulators etc, no go.

So I called Dick at Wrico LLC and he said the same thing that Clifford did.  So may be popping for a Wrico 13kw genset, not sure yet, need to get some play money together first.

So the moral of the story, before doing something - ask Clifford - Clifford, maybe I should talk to you about my living arrangements?  Maybe not.

Chuckd
Stillwater Mn
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Cary and Don
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« Reply #1 on: July 08, 2013, 02:54:21 PM »

Is this just the Powertech or are all the smaller generators the same.  We had thought of pulling that big 15K generator out of our Eagle and replacing it with something smaller.  Our 7.5 Onan always had more than enough power to run the whole coach with two roof airs,  but the GM doesn't have Cruise Airs,  the Eagle has three.

Don and Cary
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belfert
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« Reply #2 on: July 08, 2013, 03:59:20 PM »

Interesting.  Will the 8KW not start even one, or it is just an issue of starting more than one?  I'm hoping my Powertech 8KW can do three roof airs as long as they don't all start at the same time.  The load should be between 5000 and 6000 watts with all of them running
« Last Edit: July 08, 2013, 04:31:58 PM by belfert » Logged

Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #3 on: July 08, 2013, 04:15:38 PM »

This is interesting.  I would think that it is all in the numbers.  What does a Cruisair take to start up?  We have a 7.5kw and almost never run them at capacity (only two roof airs).  Of course, the rooftops are only 13500 BTU.  How big are the Cruisaires, what is their running and startup draw?  An 8 kw generator should be able to handle a good 60 amps!  I do not know your setup but find it hard to believe you installed AC's that would require such a circuit.

So there are several possibilities.  First, one could question whether the generator is truly 8kw, but even a 6kw should have no trouble running 40 amps.  Second, there could be some generator malfunction.  Third, would be to look at problems with the AC units themselves including faulty capacitor, loose or burned connections both internally or in the circuit, some compressor issues, etc.  I do not know much about these units, but do remember reading that they can develop startup problems.

Just guessing, but I would assume that you tried everything out when you first installed the generator.  If it worked then, it should work now.  Now, it is quite possible that a bigger generator would have started the AC's even though they were pulling more startup amperage than they should. However, that would not be a solution to the problem, merely a cover up that could invite other problems later.
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Geoff
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« Reply #4 on: July 08, 2013, 05:37:26 PM »

I don't know what the power draw on start up is for Cruise-airs, but I can tell you my 8kW genset with a Trace SW2500 will run the three 1500 BTU rooftop airs, even without the Trace power supplement power kicking in.

Outdated??

--Geoff
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Geoff
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TomC
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« Reply #5 on: July 08, 2013, 09:35:28 PM »

If the 4cylinder 13kw Wrico is to long, I had Dick make me a 12kw with a 3cylinder that's only 36" long-radiator not included since it is remote mounted. It is the most compact 12kw I've ever seen. Good Luck, TomC
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« Reply #6 on: July 09, 2013, 03:34:19 AM »

 You better check for proper wire size.( I bet its to small)
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busguy01
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« Reply #7 on: July 09, 2013, 04:13:03 AM »

My eagle had an Onan 7.5 quiet diesel and 2 crusieairs. Started and ran both with no issues.
JimH
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« Reply #8 on: July 09, 2013, 05:27:12 AM »

There is definitely something wrong.  Did you mean literally that "sparks fly"?
Does the engine slow or do breakers trip?
A generator shop should have a load bank to test with.  That is the first thing I would do is to be sure you are getting the full 8000 watts, and I think it should handle a surge to about 10,000.
If you can't get a load bank, then make one up with 5 or 6 1500 watt electric heaters.

Many of those generators use the same 10Kw generator head with the engine size determining the power output.
I'm guessing it may be a governor problem where the engine can't fuel up fast enough to handle the start surge.

I wouldn't give up on it without further testing.
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chuckd
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« Reply #9 on: July 09, 2013, 07:09:05 AM »

First things first, I cannot make any judgement about whether a gen set of my size will work with other ac configurations.  Haven't tried anything but my cruiseairs.

This is what the symptoms are:  The gen set works with my microwave, refrigerator and 4 1000 watts plus bus heaters - not sure whether they are 1000 or 1500 watts. 

When I try to start the cruiseairs, I go to the first switch position which is fan, and the fans come on - they draw about 3 amps.  The next position is run and when I try that position the motor decreases in speed and the voltage rises.  It reaches about 157 volts or so, then I shut it down.  The amp draw is 14 amps or so, but I do not know what the start up inductive load might be.  So perhaps it is the governor not providing enough fuel, but then why would the voltage rise.

We have cancelled our trip, or rather we are flying instead of driving.  Kathleen has to still w----, and was only going to be able to make two weeks, but I was going to take another couple of weeks or so and visit folks on the way home.  Oh well still this fall.

Clifford made the comment right away after he saw what I had purchased.  Dick or Wrico said that the powertechs do not have enough copper in them - not sure what the details .

this is what I know, what I don't know is vast.

Chuckd
Stillwater Mn
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Len Silva
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« Reply #10 on: July 09, 2013, 07:25:26 AM »

That sounds like a regulator problem.
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luvrbus
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« Reply #11 on: July 09, 2013, 07:43:59 AM »

It's a Powertech problem they used a 5.5 kw head on it for 8kw and not enough engine Bob Tiffin had to replace all the 8KW of a certain time frame in the S&S he sold they won't not run 2 roof airs my son in-law had one in his Allegro they replaced
« Last Edit: July 09, 2013, 08:25:55 AM by luvrbus » Logged

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« Reply #12 on: July 09, 2013, 09:44:56 AM »

First things first, I cannot make any judgement about whether a gen set of my size will work with other ac configurations.  Haven't tried anything but my cruiseairs.

What specific Powertech model are you running?  I'm hoping I don't have the same issues as Clifford mentioned with mine.  I will need every bit of my 8,000 watts next week.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #13 on: July 09, 2013, 10:18:33 AM »

You should be fine Brian remember the wattage is based on 80 degrees F the wattage will increase around 500 w per every 15 degrees over 80 F this from Coleman not me, plus a generator will lose some output power when outside it's operating range here in the valley the parks are full because of the 117 degree weather a 8000 will not run 3 Colemans here today they are struggling with 2

good luck
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« Reply #14 on: July 09, 2013, 10:22:56 AM »

My 10kw Powertech, which I bought in 1994, has a large end Marathon alternator head. Even when I max it out (I've had over 11,000 watts on it) the alternator head doesn't get very warm-which means it is very efficient. I looked at an Apollo genset (marine) that used a 3,600rpm belt drive, and with only a 20am load had hot air coming out of the alternator that was almost to hot to stand. See if you're alternator is putting out alot of heat or not-it is one way to tell if it is built right, or not. Good Luck, TomC
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