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Author Topic: Freq. and voltage  (Read 19446 times)

LowGear

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Re: Freq. and voltage
« Reply #15 on: November 17, 2010, 04:34:46 AM »
Holy Moly toydiesel01,

Where do you pay 39 cents a KWH?  Our record is 44 cents two years ago but we're currently on the rise and flirting with 35.

Remember that until you break even on that meter you're actually getting whatever they're charging you per KWH.  So we can make up to $550 a month in electricity and just break even with the power company.  We're miles from that dream but we need to start somewhere.  Besides, this is an economic war and ROI may not be the most important consideration on this first assault.  We need to let them know that we're seeking alternatives to their domination of our lives.

Casey
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toydiesel01

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Re: Freq. and voltage
« Reply #16 on: November 19, 2010, 12:38:35 AM »
N H

wagspe208

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Re: Freq. and voltage
« Reply #17 on: November 19, 2010, 02:26:53 AM »
Is NH state motto Live free or die? If so, it ought to be changed. LOL

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Fairmountvewe

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Re: Freq. and voltage
« Reply #18 on: December 06, 2010, 03:00:09 AM »
Just for fun, and make sure no-one is looking, try this  http://yarchive.net/car/rv/generator_synchronization.html.  We had a board at one of our power plants that still had the light-bulbs in it for synching.  I personally have never done this, but the theory works, and what the heck....
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DRDEATH

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Re: Freq. and voltage
« Reply #19 on: December 14, 2010, 01:16:35 PM »
OK I am sure this has been discussed in the past but I need to bring it up again.  50 HZ vs  60 HZ. I am one of the people getting a SOM from the UK and in the past I have heard all of the problems that this will have in US homes. Well I was told this is not the problem that is use to be because quite a bit of what we use in the US will work. So I started looking at some of our toys we have in our house and I was surprised to find our computer states it right on the black cube that runs it. 50 to 60 HZ. 110 to 240 volts. Now I have not pulled out our 2 new flat screens but we got them last year and I am pretty sure China had something to do with them. I know this because I got them from Wal Mart. THE DEVIL  I haven't looked at the refrigerators and freezers yet but the fridge and one freezer is less than 3 years old. I am in contact with someone who has owned a SOM for several years and I sent him an email to see how he has dealt with this problem. He just happened to contact me to get an engine included in on the container we are working on over there. So is there anyone else who is using a 50 HZ unit or has more information on just what will and wont work. I know newer air conditioner units will work because as usual China is making them also. Thanks, Mike DD
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mike90045

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Re: Freq. and voltage
« Reply #20 on: December 15, 2010, 01:03:51 AM »
You can either increase RPM a little bit till the alternator hits 60 hz, or you could change a pulley size.


Generally, electronics don't care, but motors would run at a different speed.  60hz generally, is more efficient for the same motor, load and other things being equal. (you ought to see what 400hz military gear can do in a small package)

Doug

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Re: Freq. and voltage
« Reply #21 on: December 15, 2010, 02:31:12 AM »
Thats over simplified.

Efficiency has as much to do with frequency as design and era.....

I could write a book about core densities and air gaps and still not cover all the details.

In this case a 20% increase in speed is probably not an issue and might increase the rating of a SOM 10%.

What about a common point? Are English SOMs built for Eddison 3 wire?
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DRDEATH

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Re: Freq. and voltage
« Reply #22 on: December 15, 2010, 04:03:30 AM »
Doug I am told increasing speed should be the last resort since they also run 24 volt charging system. As for the 3 wire it is my understanding they are straight 240 volt 2 wire. I am told that is not such a big issue with a transformer for 110/240. It is just the 50 Hz that might be a little harder to cope with. If nothing else I will use converters and run 110 off battery bank. There seems to be wealth of knowledge and it seems it is all gray area. Not much black and white.
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Doug

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Re: Freq. and voltage
« Reply #23 on: December 15, 2010, 07:19:34 PM »
II looked at a SOM print a few years back.

As I recall there was a way to adjust the charging voltage.

And so what if there isn't?
5 - 6 volt batteroes wopuld crank the old girl over just as easily as 4.....
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vtmetro

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Re: Freq. and voltage
« Reply #24 on: December 15, 2010, 07:41:30 PM »

listeroil

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Re: Freq. and voltage
« Reply #25 on: January 30, 2011, 11:21:34 PM »
DD  &  List

On a SOM it should be possible to increase the generator revs to get 60hz. (maybe by having the generator pulley machined down rather than increase engine revs)
Then adjust the field voltage down via the big fat resistor to 220 volts AC
Then also adjust the big fat charge resistor down to produce 26 ish volts DC to charge the batteries.
It should be quite easy to do. That how they work and no problem with the higher revs from 1500 to 1800.
Oh yes SOMs are defiantly 2 wire.

Mick

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Re: Freq. and voltage
« Reply #26 on: January 31, 2011, 01:10:46 AM »
DD,

Don't run your house in the US at 50hz.  It can cause you a lot of trouble.  Most small AC - DC power supplies can handle 50hz, but your appliances or HVAC won't like it.  I would take Listeroil's advice and get another pulley to run your alternator up to 1800RPM.

Regarding the 120 - 240v issue, you could install a 240V - 120V/240V transformer or a 240V - 120V transformer (not center-tapped) to derive 120V.  Your best bet IMHO(if you want to use the existing generator head) is to use a transformer with a center-tapped secondary to derive the 120 legs.  Ground the neutral (center tap) at the transformer or the subpanel, but not at both.  As with the generator, make sure you don't back feed the transformer from the utility.  If you could get a small transformer with taps, you could also adjust the secondary voltage if needed, usually up to 5% in 2.5% increments.

Also, be aware that the generator head may be grounded to the chassis on one leg. 

Hope this helps,

Sparkie 

listeroil

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Re: Freq. and voltage
« Reply #27 on: January 31, 2011, 02:00:46 AM »
Good point about one of the AC  terminals  connected to earth it is.
The AC neutral is connected to earth.
Also the DC negative is also connected to earth.

Mick

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Re: Freq. and voltage
« Reply #28 on: January 31, 2011, 03:32:26 AM »
I have seen one engine here in the Bahamas equiped with the switchgear to be a SoM, but was long since outta service as such. Most of the systems I have seen here were brought in the 60s-70s and were "semi-SoM". Most were VAs on cast or fabbed frames, with a push button on the doghouse that would allow hands free starting, except for the decompress and fuel lever. They are also 240v with 3 wires for 2 legs of 120v, at 60hz.

Rom

listeroil

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Re: Freq. and voltage
« Reply #29 on: January 31, 2011, 04:30:29 AM »
Rom

I was refering to the SOM that DRDEATH has bought from the UK. All the UK SOMs that I have come across have only got 2 AC brushes for the output and they are designed to produce 230 volts AC at 50hz.
I think you are talking about export models and I am sure your correct about dual voltage and 3 wire but I am talking about the UK spec generator that he has bought in the UK.

All the best Mick