Author Topic: some advise please  (Read 20763 times)

stevo42

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some advise please
« on: September 17, 2014, 05:51:19 PM »
Greetings folks, newbe here. I've had a stand by generator for years and used it for long periods during winter power outages, although now that the roadside trees are being more aggressively trimmed, not as much anymore, but I still need to feel I can be independent of the grid if need be as we live on an island.  I have a Lister SL1 that was completely rebuilt just before I got it, so it’s a strong little engine, hand crank, a real sweetie, my wife can start it, no problem.  I have it running one of those 2.9KW "Northern" heads, infect I have a spare, I know, I should have went with the ST head but, didn't know any better at the time.  I'm happy with the power output as we heat with wood and cook with propane, no need for more power in the house (all 120v) and I can run my 240v deep well pump or a tool in my shop if I have to.  This system has worked for several years but an opportunity to upgrade has come my way, the big brother to my SL1 so without going into details about the SL2, except she starts right up, no smoke, I'm trying to figure how to set up my new system as I have just ordered a ST5 gen head from Tom Osborne. I'm no electrician although I did do all my wiring, but if its not in the "Sunset Home wiring" book I may be in trouble. I keep an eye on the wattage gauge on the transfer switch and see that the load stays somewhat balanced, this is still with the 2.9KW gen head so a question I have is, should I wire the new ST5 head for
120v only? I think it would be most handy to go 240/120 then I could run the house and 240v pump with either Lister.  If I dedicated the new SL2 Lister and ST head to 120v it wouldn't be able to run the pump or shop I'm trying to have a system that will be good for a short power outage or a long power outage.  Both Listers will have the same size (7&3/4) pulley so they can run either head which is another reason to have both heads 120/240.  I don’t need 240v much when the grid goes down but I do need it, mostly to run the pump once a day or a power tool in an emergency.  I hope all this makes sense

  Thanks, Steve
« Last Edit: September 17, 2014, 11:42:27 PM by stevo42 »

Tom

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Re: some advise please
« Reply #1 on: September 17, 2014, 05:58:51 PM »
Welcome aboard! Well you can do like I did with an ST5 and run everything through a load balancing transformer. The only downside I've found is that when running a highly unbalanced load the xformer gets warm.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

BruceM

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Re: some advise please
« Reply #2 on: September 17, 2014, 06:45:00 PM »
+1 for Tom's suggestion. The balancing transformer Tom mentioned is a special auto transformer for exactly your situation.  The ST will then see only a balanced load.

I don't remember the cost of that unit, Tom, could you provide some particulars?

Plan B would be to configure for 120V and then use a step up transformer for the well/shop 240V.
« Last Edit: September 17, 2014, 06:52:02 PM by BruceM »

stevo42

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Re: some advise please
« Reply #3 on: September 17, 2014, 11:52:02 PM »
A load balancing transformer or a step up 120V to 240V transformer, Humm,  I know nothing about either, something to look into. Which would be easier for a novice to deal with?  and price?
« Last Edit: September 17, 2014, 11:55:50 PM by stevo42 »

tiger

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Re: some advise please
« Reply #4 on: September 18, 2014, 04:42:38 AM »
A load balance transformer is not a auto transformer exactly, the primary is, in that it is designed to accept many input voltages 120 to 480 volts typical. the secondary winding is designed to produce 120/ 240 with a center tapped neutral. So one takes the 240 volt taps from the generator head , float its neutral and hooks up the secondary center tapped neutral to the load, and the secondary 240 volt legs. the medical xray industry has used these for years, new techniques have made them obsolete . typically they produce 5 kw continuously and 8 kw momentary. I have 2 . check your local docs, hospitals ect. they are selling them for scrap now.
Metro 12/2 ST 10 KW

BruceM

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Re: some advise please
« Reply #5 on: September 18, 2014, 05:50:06 AM »
Here's the one I had vaguely remembered from a post on the microcogeneration forum:

http://www.altestore.com/mmsolar/others/PSX240%28900-0043-1%29.pdf

Note that the configuration used for load balancing is very unusual.  This is being used as an autotransformer, not an isolating transformer with primary and secondary. 

For just a basic step up or down transformer, you can get those on ebay fairly cheap.


ronmar

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Re: some advise please
« Reply #6 on: September 18, 2014, 06:04:02 AM »
Or simply do your best to keep the loads balanced and wire it into the panel as 120/240.  The transformer helps to balance things out, but will cost you fuel to do so(warm xfmr = fuel not powering your house).  Balancing a panel isn't terribly difficult.  An inexpensive clampon amp meter is fastest, but a little nameplate adding of the loads on the circuits will get you close enough.  As long as the loads are reasonably close, this shouldn't be a problem...  I like versatility, never can tell when you have to figure out how to do something you never thought you would have to:)

Welcome Aboard, and Good Luck...
PS 6/1 - ST-5.

stevo42

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Re: some advise please
« Reply #7 on: September 18, 2014, 04:21:36 PM »
Thanks for all the feedback, I'm leaning toward setting the new ST5 up for 120v/240v for now and trying to find some very basic info on these things you good folks speak of.   Its funny, I've been around generators all my working life, having retired from running commercial boats, and know next to nothing about them except how to fire them up or shut them down if the engineers not around. I'm setting up a new 8x8 engine room so that will keep me busy for a while and in the meantime maybe I can learn a little.  Thanks again

xyzer

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Re: some advise please
« Reply #8 on: September 18, 2014, 05:10:56 PM »
steveo,
Do you have a 220volt panel at the house for the pump and house requirements?
Dave
Vidhata 6/1 portable
Power Solutions portable 6/1
Z482 KUBOTA

Hugh Conway

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Re: some advise please
« Reply #9 on: September 18, 2014, 05:14:57 PM »
Welcome Steve
I am all for simplicity. Ronmar's suggestion of balancing via the breaker panel works for me.  Using a 6/1 with PMG. Our 3Kw gen is wired 120/240, we just rearranged the breaker panel to ballpark balance the normal operating loads. Our only 240v loads are a deep well pump and a very small load from the fridge. have not had any problem with the set-up. You might try this option first, as it costs you nothing. Can always try the other options if required.
Cheers,
Hugh
JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

Tom

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Re: some advise please
« Reply #10 on: September 18, 2014, 05:36:10 PM »
In my case balancing the load was not a viable option. With some loads like a 120v water pump, microwave and 120v welder it was not uncommon to see a 15v difference from side to side. Now with the xformer it's rare to see more than a 5v difference. My xformer was a free gift from a pile of used xformers from where I used to work. It's a 2.5 kw rated unit. So it's about perfectly sized to handle a total imbalance on a ST5 and since the Listeroid only has the ability to make 3kw this xformer is not stressed.

My system is wired like this diagram.

Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

bschwartz

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Re: some advise please
« Reply #11 on: September 18, 2014, 09:29:25 PM »
I see a lot of good suggestions, but I'm curious...... What is your goal for load balancing?  Is it to prevent drawing too much current from one leg of the generator and causing damage, or is it to prevent the head from 'growling" ??
-Brett

1982 300SD, 1995 Suburban 6.5, 1994 F250, R170, Metro 6/ sold :( , Witte CD-12 ..... What else can I run on WVO?

Tom

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Re: some advise please
« Reply #12 on: September 18, 2014, 10:22:42 PM »
In my case, running the microwave would drag the voltage down enough to (108v) cause the inverters to switch out the generator input until the generator stabilized and then the cycle would start over again. Adding the xformer helped a lot and fine tuning the governor spring did the rest.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

tiger

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Re: some advise please
« Reply #13 on: September 19, 2014, 02:39:33 AM »
bschwartz: my wife just turns things on, so missed balance is the norm.
Metro 12/2 ST 10 KW

ronmar

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Re: some advise please
« Reply #14 on: September 19, 2014, 07:26:37 PM »
A microwave is a tall order on a 3KW genset.  It is the worst single load I have.  SInce it is an infreguent load, I decided to balance that load all by itself.  I bought a 240-120 transformer and put a dryer plug on it.  I plug it into the dryer outlet and plug the microwave into it's output.  This places this large single load across both 120V legs maintaining balance...  The 240-120 transformers are a fairly common item used to adapt US consumer appliances to the european 240V standard, so they are not terribly expensive...
PS 6/1 - ST-5.