Who Glyptal's their generator head?

[sailawayrb]

Sail and Doug, I think you are both right.

Your diplomacy is appreciated, but I am 100% right.
 
If you wire your ST for 240V and you don't balance the electrical loads, you can expect your ST to groan.

If you wire your ST for 240V, you can only get half the rated power out of it.

If you can't figure this out from the schematic, than try it out and prove it for yourself.

[apogee_man]

"...but I am 100% right."

"If you wire your ST for 240V, you can only get half the rated power out of it."

I'd for one would be VERY interested in your explanation of why this is??

Steve

[Tom]

Sailawayrb,

Sorry, but if you place a 240 volt load on the system you can indeed get full rated power out of it. Or a balanced 120 volt load on each leg like I do when charging batteries. Or if you using a balancing transformer.

[sailawayrb]

Sorry, but if you place a 240 volt load on the system you can indeed get full rated power out of it. Or a balanced 120 volt load on each leg like I do when charging batteries. Or if you using a balancing transformer.

Tom, sorry but your statement is only 50% correct...   If you wire your ST for 240V and you are ONLY using it to feed 240V circuit(s), YES you can use the full rated ST power output for your 240V circuit(s).

However, if you wire for your ST for 240V and you have 120V circuit(s) that you need to feed, you can only use half the rated ST output power for any given 120V circuit.  Likewise, you can also only use half the rated ST power output for each side of your transfer switch panel.
 
So if you have a single 120V circuit that requires high power, or if you have several circuits on one side of your transfer switch panel that in combination require high power,  you may not be able to get there when your ST is wired for 240V.

If you wire your ST for 120V, you can feed BOTH sides of your transfer switch the full ST power rating and you can therefore also feed ANY single 120V circuit in your panel the full ST power rating too.

Furthermore, and more to the point of this thread, if you wire your ST for 120V, your ST is ALWAYS electrically load balanced and you will NEVER experience the so called ST groaning caused by electrical load unbalance.  This is NOT the case when you wire your ST for 240V...you would have to manually accomplish the 120V circuit load balancing in order to avoid the groaning.

For these reasons, I would only recommend wiring your ST for 240V if you have 240V circuits that you absolutely must feed.   If you also have 120V circuits that you must feed, than the transformer approach makes very good sense.

[Tom]

Sailawayrb,

Please reread my previous post and take notice of the mention of a balancing transformer. Then do a search on the subject on this forum to find out what they are used for. You might be surprised.

[Doug]

I know it would work Tom but I am not sure its cost effective to use. You have to bond the common at generator and tye the common in at the transformer. In the end if the genrator has one leg running a few volts lower than the other the net effect is wasted power again because of the circulation and extra excitation currents. I'm not saying its totaly impractical but its something that has to be considered.

You need to be ballanced and pulling at least 75% load for an extended period to get the engine warm in winter and running efficiently. It makes more sence to wire it up for convensional eddison three wire and load the thing down. Even if it means running things you don't need. The fuel penalty is low for that and it will prevent glazing the cylinder liner as well as running the engine and gen in an area where it starts to develop its efficiencies.

However if he can't figuere out to wire things and run so his load is ballanced not much advice from anyone here can do

[sailawayrb]

Sailawayrb,
Please reread my previous post and take notice of the mention of a balancing transformer. Then do a search on the subject on this forum to find out what they are used for. You might be surprised.

Tom,
I am fully aware of how a balancing transformer operates.  In fact, I stated in my previous response to you that it is good approach IF you have 240V circuits that you absolutely must feed and IF you also have 120V circuits that you must feed.  If you only have 120V circuits to feed, a balancing transformer is not needed at all since a ST that is wired for 120V is always balanced and you won't hear any related groaning either. 

I suspect that there are folks who wire their ST for 240V when they are only feeding 120V circuits (based on miss-information prorogated by clueless Hero members) and then wonder why they hear groaning.  And when they question why they can't seem to get the full ST rating to one of their 120V circuits, they get told that STs are pieces of junk.

You transformer side track to obfuscate the debate is interesting, but I am still 100% correct, you are still only 50% correct, and Doug is still 100% wrong.

[Doug]

So be it.

There are plenty of different ways to skin a cat. The question is what is right for the person putting a system in and how they feel it will best fit their needs.

Sailawayrb there are many good books on the subject of home power and excellent college text books that explain the forces and physics at play in electric machines. Life should be a constant study in adapting technology to meet our own needs or one can simpy sit back and do what others tell us and hope we are listening to the right advice.

But in the end its up to you or me or the next guy to decide what he wants. I hope others reading this thread make informed descisions and carefuly research things before we commit themselves to plan.

Under different conditions, if the STs were a little better made and designed I would probably a pure 120v system if I had no 240 loads. But we live in a world wired for Eddsion 3 wire ( North American style residential systems that is ) and most people have mixed loads. 

[mike90045]

It is also well known that you can only use half the effective power of your ST if it is wired for 240V.  You should only wire for 240V if you have circuits that require 240V.

Well Damm !   I'm not sure how this works.   I've ordered a 240V charger/inverter, because I knew of 120V  un-balance problems with the ST, but now wired for 240V, I can only get half power? I'm going to have to run this sucker for hours and hours to charge batteries then.  And tomorrow is listeroid delivery day (D day) if the freight company can be trusted.

[Tijean]

Na, dont worry, if it is a 240 V unit you can unload the whole rated output into it.

 I think it was not entirelyl clear, but the only circumstance where you can utilize only half the rated output is when the gen is connected in series for 240 and the total load in question consists of 120 volt item or items  applied to only one leg of the gen. output. The other leg will not load share so its potential output cannot be accessed.

I am in the same 120 / 240 combination of needs part of the time but dont like to listen to the growl whenever the 120 loads are even slightly unbalanced. Wish there was some simple switch gear to change back and forth.

[bschwartz]

The easiest way to stop the growling (and keep 240) is a transformer.  It doesn't get hooked up to change the voltages, just to balance them.
http://www.weirdstuffwemake.com/sweetwatergems/geek/images/balance_xformer2.jpg

Just attach three wires, and you're done.  I picked up a 3K buck/boost unit on ebay for under
$75

[Doug]

You can use any industrial transformer to do the same thing just be sure if it has a 600v primary ( or 480 in the USA ) that you cap the leads and tape them. You don't want to energize the shell of the transformer.....

This does add one more parasite load and circulating current to your power system though and you need to decide if this is realy going help. You may find you are buring watts for nothing with this where you could have been using watts for some other purpose while ballancing the load.

[bschwartz]

More importantly than just reducing groan, it helped level out voltages between the two legs when an unbalanced load was put on them.  I had voltages on a loaded leg fall to 108v while the unloaded leg jumped to over 132v before using the transformer.   It may have cost a little in efficiency, but may have saved some of my electronics from over-voltage situations.

[Doug]

That us true but the point missed here seems to be you need to ballance your load. A transformer will do that for you but you are throwing away power to achieve it....

If unloaded you have 123 volts on one leg and 130 on the other that transformer will pull the two together and waste 7 volts times the amount of current required to do it PLUS the copper losses iron losses in the transformer. This is something you all need to be aware of if one leg sags more than the other under an equal load because of differences in the winding and flux gaps at the poles again moire power will be consumed by the transformer to correct this., However if you ballance the load and didn't try and correct for this you may well have ended up saving fuel....

The fuel saving may be more than the bennifits of regualtion are worth at 108 on one leg and 132 on the other, that and a better AVR.... 

[Tom]

Point well taken Doug, however can you explain to my wife that when she runs the microwave she needs to run the vacuum and toaster at the same time.