Author Topic: Freq. and voltage  (Read 19449 times)

wagspe208

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Freq. and voltage
« on: October 21, 2010, 05:56:49 AM »
I am planning on (planning... investigating) using a cs10-2 or 12-2 as a source to drive a generator.
My questions are:
1) How good of a job does the governor do on these pieces? (meaning my fridge compressor turns on, does the rpm drop 100 rpm? or just keep going)
2) As/ if rpm's decrease/ increase the voltage output and frequency output (HZ) must change. How does this affect being tied into the grid?
3) How sensitive are my electronics to those changes? Meaning, will it kill my big screen TV, computer, etc??

The GF has a gen. she uses as a backup and the gov rpm's must be off as her clocks change a few minutes a day if she runs it continuous. (regular commercial gen bought for emergency use)

Thanks
Wags
Novo Type "S" 4hp
Lister 8/1
Engine machinist for 20+ years. Glad to help anyone out.

LowGear

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Re: Freq. and voltage
« Reply #1 on: October 21, 2010, 06:00:01 PM »
Hi Wags,

I've been trying to find out how to sync an AC generator to the grid for years.  I don't have a staff of even two.  My bent at this time is to rectify it to DC and plug that into an approved grid tie inverter.

The local power company has absolutely no sense of humor or adventure!!!

Casey
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bschwartz

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Re: Freq. and voltage
« Reply #2 on: October 21, 2010, 07:04:57 PM »
Wags,

Unless your engine is running at EXACTLY the correct speed to keep your gen head turning at EXACTLY the right speed (typically 1800 RPM, or 3600 RPM) then your frequency will be off the magic number of 60 Hz (our grid here is actually 59.9).  Voltage can swing quite a bit and most electronics wont mind too much as long as it is between 108v and 125v.  But if the frequency is off, clocks will run fast or slow (yes even electric digital) and things like microwaves REALLY hate being far away from 60 Hz.  As for the question of RPM drop, these big flywheeled slow speed engines grunt momentarily, and keep on chugging when a load such as a fridge turns on.  RPMs shouldn't change enough to cause a problem.  Big screen TVs and computers have their own power supplies built in that change the input voltage anyway, and I've NEVER heard a complaint from either in my house.

Now grid tie is another thread entirely!!!!
-Brett

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

wagspe208

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Re: Freq. and voltage
« Reply #3 on: October 21, 2010, 09:14:40 PM »
So, it sounds like if I have a transfer switch and am truly off grid, I will be ok. But if I tie in, I better go the dc gen and inverter way.
I wonder how much a windmill gen and inverter costs. They do everything at the top (bigger systems) and clean power comes down at the bottom.
Wags
Novo Type "S" 4hp
Lister 8/1
Engine machinist for 20+ years. Glad to help anyone out.

LowGear

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Re: Freq. and voltage
« Reply #4 on: October 21, 2010, 11:00:20 PM »
Hi Wags,

My understanding is that the SMA Sunny Boy and Windy Boy are the same hardware only different selections made on the inside software that they all carry from the factory.  You might do a search on this site for "Sunny Boy Windy Boy".  Please don't take any of my posts as more than dangerous neophyte dribble.

If you find a better way please share it with the couple of us that are chasing that fantasy on this website.

Casey
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ronmar

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Re: Freq. and voltage
« Reply #5 on: October 22, 2010, 12:13:17 AM »
If you keep the load within the rated HP spec of the engine, you should have no problem maintaining +/- 2HZ.  That of course is also provided the governor linkage is properly maintained and adjusted.   If you ask your utility what their advertised spec for freq, they will probably advertise +/- 5%, which is 3HZ...
PS 6/1 - ST-5.

LowGear

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Re: Freq. and voltage
« Reply #6 on: October 22, 2010, 01:12:52 AM »
And that local utility would be a good place to augment your search for syncing your AC generator to their grid.

Casey
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wagspe208

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Re: Freq. and voltage
« Reply #7 on: October 22, 2010, 04:52:30 AM »
OMG! Those big watt inverters are high $$!
A buddy of mine sells and install windmills. Ok, an acquaintenance. I got him started in bio diesel.
I will check with him and see if he can do us any good.
He may only get complete stuff, not parts, but I will see him next month. I can try and call him, also.
Wags
Novo Type "S" 4hp
Lister 8/1
Engine machinist for 20+ years. Glad to help anyone out.

mike90045

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Re: Freq. and voltage
« Reply #8 on: October 22, 2010, 08:37:34 PM »
I wonder how much a windmill gen and inverter costs.

Unless your hat is blown off your head every time, you are not in a good site for a wind generator.

If you still insist - please check Hugh Piggott's Homepage http://www.scoraigwind.com/  and OtherPwer http://www.otherpower.com/ and at least learn the lingo before spending money

buickanddeere

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Re: Freq. and voltage
« Reply #9 on: October 22, 2010, 10:26:21 PM »
  Unless the engine is equipped with a governor capable of both proportional and integer control.  A plain proportional control does well to keep rpms within a 10% band.

LowGear

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Re: Freq. and voltage
« Reply #10 on: October 22, 2010, 11:49:10 PM »
Wow, I wish I knew what buickanddeere just wrote?

How come we just can't mount a windmill wind turbine generator onto our units and go waste oil wind technology?

Casey

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dpollo

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Re: Freq. and voltage
« Reply #11 on: November 11, 2010, 01:34:32 AM »
Buickanddeere is correct. 

 If you truly do not understand the implications of tying a small unit into a major system where frequency matching is imperative, then KEEP your system independent.  My 2 cylinder Lister governor keeps the frequency (speed) bang on for all practical purposes.  Clocks may gain or lose time depending on where the frequency is for the bulk of the time.  No Problem. BUT I AM NOT TRYING TO TIE IT INTO THE LOCAL GRID.

 When I was a boy in the  1950s, I would watch my Uncle, who was superintendent at Jordan River compare the Telechron electric clock with a Chronometer and adjust the speed of the generators if needs be.  This plant lit up the city of Victoria BC.  Bringing another unit on line required experience and skill since it was best to close the switch just as the frequency (speed) of the unit to be engaged was approaching 60 cycles.  If it was allowed to go past, then you slowed it down and started again.   This is not something an amateur should attempt, especially with a home unit being tied into a utility.

 

wagspe208

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Re: Freq. and voltage
« Reply #12 on: November 11, 2010, 03:47:08 AM »
Fair enough. So just get a high amp transfer switch and be happy with the savings as opposed to trying to sell power back?
I could transfer to gen power most of the time and go to grid when high loads were necessary.
Wags
Novo Type "S" 4hp
Lister 8/1
Engine machinist for 20+ years. Glad to help anyone out.

listerdiesel

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Re: Freq. and voltage
« Reply #13 on: November 16, 2010, 07:39:43 PM »
I have no need for this setup at home, we have fairly reliable mains power in the UK, and a couple of small gennies if we need short-term power for anything. The noise of a small genny running during the day isn't a problem, but I wouldn't like to have one running in the evening or at night, even if there was a power loss.

We have had two breaks in 24 years at this address.

As far as putting power into the grid goes, I have been involved with larger systems, over 100kW, that did supply power back into the local grid, but it was never economical at the rate that you were paid for the power, it was a consistent loser.

At the low power end of the scale, the economics are even worse, and I'd never recommend doing it or buying the kit to do it unless you have a cast-iron costing of the scheme that shows you coming out at break-even or better, costs for wear and tear and equipment replacement included.

For generation away from the grid it is a good option, especially if used with power storage and other means of generation such as solar and wind, but you'll never make money out of selling to a utility.

Peter

toydiesel01

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Re: Freq. and voltage
« Reply #14 on: November 17, 2010, 01:12:48 AM »
I started doing some reserch on sell power back to the grid.  You need state licienced electricians for everything
very expensive special grid tie boxes, with the grid feeding the box so you can feed the grid.  What you pay for electricy will not be what the electrical company pays you per kwt.  Example you pay .39 cents per kwt they now pay you .02 per kwt.  You won't break even for a hundred years, providing no break downs or upgrades required.

By modifying the goveror I get a better power than what my electric co sends to me.  Even under some heavy loads my gen runs very stable- maybe drops 3 volts and 2 hertz but not much more than that.  Those big flywheels asorb a lot of surges, unlike the fast turning machines the engin needs to absorb the serge and the governor need to react quickly.

my 2 cents worth