Help Me Design It

[BruceM]

Ron, Please tell us more about your HE washer.  How do you capture the heat and return it back to supply, when supply and waste are happening at different times?

Or does HE mean high efficiency, not heat exchange?

[Sodbust]

The first ice storm we had right after I got my 6/1 ST 5kw set up for back up power. I got it running and had to go feed the livestock.. I gave the wife a simple command to run just one item at a time until I got back to expand on the concept later.

Well I had allot of problems, and time got away from me.. By the time I got home it was dark 30 and as I came into view of our house the lights were all but flashing on and off..  Not only did she have about every light in the house on but the elect oven, water pump and dishwasher.  I raced to the Listeroid that was just able to run at 250 rpms with the 10kw load asked from it. 
So,, a real deep breath later we started all over with the explanation of what 1 item on at a time meant.

No harm done,, and goes to show the over load limits this type of set up can endure.
Sodbust

[vdubnut62]

Could someone explain (simply!) why and how a transformer to load balance is used? What sort of transformer, how is one sized?
Is it a special type? If this has been covered elsewhere I apologize, kindly point me in that direction.
Ron

[mobile_bob]

i believe what is referenced is a step down transformer to take the total voltage (240) from the st head
which is comprised of both legs, which effectively balances the load between both legs, to 120 volts for those loads that
need 120.

this way your 120 loads are provided evenly across both legs of the st head, and it allows you to have 240 as well straight off
the st head.

otherwise to get a balanced output from the st head for 120 one would need to connect the two legs in parallel, this gets you the
120 that is needed but you don't have ready access to 240volts without reconnection.

so you would need a step down 240 to 120 transformer that is rated at a bit more than what your engine can drive, basically
a 4kva transformer should handle a 6/1 driven st 5 generator, probably easier to find a 5kva though as it seems like that is a popular
size in my travels.

that being said there is no reason to go with even a 4kva transformer if your intended loads are lower for the 120volt loads
although i would probably oversize it a bit, for instance if your loads are anticipated to be 1kwatt, i might go ahead and spec out
at least a 1.5kva and better a 2kva unit. this would provide some extra capacity for future growth or power factor issues.

hope that is helpful

bob g

[BruceM]

I use the setup Bob describes on my ST-3 head.  My ST-3 is set up as 240VAC (two 6 gauge wires for the 100 ft to pump/battery bank house and  then 350 ft to the shop).  I have 3200watts of toroidal step down transformer (4 surplus, tested, matched, 800 watt units in parallel) for 120V loads at the distant shop building.

[WGB]

OK Bruce, what is a toroidal transformer,circular core?
How can you tell from a standard transformer by looking at one?

[BruceM]

Yes, Toroidal transformers are donut shaped. I like them because they are higher efficiency, and have much lower stray magnetic fields. That's important  to me because 60Hz magnetic fields aggravate my epilepsy and give me whopping headaches.  Using toroids, I don't have to have so much distance.

A good conventional E-I type transformer is 85% efficient, toroids 92%.  The difference in stray magnetic field is huge.

Conventional transformers are much cheaper. 

Bruce

[Ronmar]

Bruce, HE stands for high efficiency.  It only uses about 12 gallons of water per load, compared to the 30+ gallons the traditional top load washer consumed.

My small microwave consumes about 1.5KW and is the largest single 120V load I have.  Since it is half my rated output, it really loads down one 120V leg when in use.  The transformer I am using is a conventional transformer, commonly available to adapt US appliances(120V) to european power(240V).  I sized a 3KW continous transformer and attached a electric dryer plug to it's input.  The laundry room is right next to the kitchen, so the microwave gets relocated to the top of the dryer when cooking on generator power... 

[BruceM]

Thanks Ron,  Knowing your ingenuity with heat exchangers,  I was imagining some sort of washer waste water heat exchanger/storage.  Reducing the water use by 2/3 is far more practical!

[Tug]

My 12/2 is belted to a ST 12kw....
It will run a standard washer,dryer and shallow well pump....just a little puff of black smoke when the pump kicks on...
But thats it...no more load...
I remove heat from the cooling system to help heat the water for the washer..
Hope this helps
Cheers
Tug

http://www.youtube.com/watch?v=77wiB_lKtog

[oiler]

Bruce, HE stands for high efficiency.  It only uses about 12 gallons of water per load, compared to the 30+ gallons the traditional top load washer consumed.

12 GALLONS!!!!!!!!!! Must be a huge washer. Our Siemens uses from 12 to 20 litres and 1.05 to 1.3 kwh of power depending on program........

Interesting idea to heat a dryer from your pellet stove. Please let us know how it goes.

[Dail R H]

    Help me make sure I understand this right. If I want to use 120v from my generator, I should do it with a transformer,not split the legs so to speak? That will keep voltage the same on both legs,n make life easier for the gen?
   House will probably be located somewhere in central / southern WV. Most likely 24 x 24ish. I have a sawmill,and will do most of the work myself,'cause I ain't got money to pay anybody,and 'cause I'm so onery noone will stay around me for very long ha ha.

[Ronmar]

    Help me make sure I understand this right. If I want to use 120v from my generator, I should do it with a transformer,not split the legs so to speak? That will keep voltage the same on both legs,n make life easier for the gen?
   House will probably be located somewhere in central / southern WV. Most likely 24 x 24ish. I have a sawmill,and will do most of the work myself,'cause I ain't got money to pay anybody,and 'cause I'm so onery noone will stay around me for very long ha ha.

No, you don't have to use a transformer to use 120.  But, when you are working with as little power as I am(3KW), each load in the house can be significant.  The electrician who sets up a home power panel, does their best to balance the loads between the two 120V feeds into the typical US domestic panel.  This is even more critical on a generator, as imbalances are innefficient and cost you fuel.  I chose to use a transformer to feed one specific load, a small microwave oven.  It uses about 1.4KW with a mediocre power factor, so it's use applied to 1 leg of a 3KW generator has a significant impact on that leg, and all the other devices running on that leg at that time.  By plugging it into a 240-120 step down transformer, that single load no longer has the impact it does on a single 120V leg, and you have no hint it is really in use...

[vdubnut62]

Ok now It is the time we ask really really stupid questions and we promise not to make fun of each other.
Can I rewind a really big (heavy)arc welder transformer to accomplish the 240 to 120 conversion?
Please, throw no rocks, rotten fruit is ok..
Ron.

[Ronmar]

Ok now It is the time we ask really really stupid questions and we promise not to make fun of each other.
Can I rewind a really big (heavy)arc welder transformer to accomplish the 240 to 120 conversion?
Please, throw no rocks, rotten fruit is ok..
Ron.

Yes, but why would you want to...  2:1 transformers are pretty common items.