generator questions

your thread turned into an electronics class !!!

I agree with the post about the the transfer switch... I just installed a 30kw generac with auto transfer... sweet... auto exercise, auto switch over... I love it..

Before I had a surplus military 7kw unit with a 100 amp double pole manual transfer switch... (the brand is a RONK)It"s sitting on my workbench in the way . If you"re interested drop me an email and let"s talk... I"m in Birmingham, Al.. It"s about a 200 dollar switch and has been thrown about 3 times... I"ll make you a good deal on it if you"re interested...

later
John
[email protected]

Link href="http://www.schneider-electric.ca/www/en/press/html/fpse.htm">Link
Link

Use one of these or your/your estate/family/friends will risk being sued, injured or killed. >Link
Link href="http://www.schneider-electric.ca/www/en/press/html/fpse.htm">Link
Link

The electrical inspectors, emergency response personal, prosecutor have all heard these words. "It was only temporary, I knew what I was doing, I don't know how that happened, I wish I had done it right, etc." Nobody is too smart or too careful and is always able to avoid making mistakes. I just about got blown away with 4160V about 4 o'clock one Sunday morning night shift. Besides a transfer switch is just a few bucks, so what.

While I've seen plenty of 'peak' reading meters.. and a few less peak to peak scop type meters, the vast overwhelming majority of consumer grade vom's just read RMS..( root mean square ). can't say that I've seen any consumer grade equipment that read average... though it wouldn't be hard to calculate, if you know RMS, peak, pr Peak to Peak value... etc..

Soundguy

The conversion from peak to RMS by the .707 factor times peak only works for a pure sin wave. A complex or dirty sin wave that comes out of some generators gives erroneous readings.

Average voltage is not really used for much although there are some meters that �read� the voltage as average voltage but are usually calibrated to show RMS.

The old moving vane type voltmeter actually �reads� average voltage and the scale is of course usually calibrated in RMS.

Regards
Gary

I also think you are not giving credit to more modern generator output cleanliness.

I've scope'd quite a few gennies, ranging from small honda 1000w units to 10kw hobart welder /gennies.and my and my stepfathers 12 and 24 kw pto gennies. All had good sine waves, and actually had better voltage stabilization that the utility, as long as you kept the load within the range supplied by the genny.

I did side by side tests on utility vs my pto gen, and utility vs a gas powered 10kw gen on various motor loads, including a well pump. I must say.. the voltage stabilization was far superior with the genny's. Didn't capture any distorted wave forms, and couldn't find any 'noise' on them either.

If you are looking for noise..look at UPS and Inverter based systems. Even the high dollar ones tend to kick some noise and funny approximated sine waves, and many other sinusidal waves. Most devices are fairly tolerant of some wave form variation these days.. but I can remember when ferro-ressonant power supplies were in use.. they did not like approximated or otherwise stepped sine wave outputs.. including cheap square and triangle -ish type wave forms..

My previous post exactly spelle dout what I had issue with. You were refering to 'average' reading vom's. As has been hashed out, most vom's display in rms. And as has been said.. you don't see too many consumer grade vom's that will display in 'average'. My issue was that mentioning the 'average' may confuse the issue with electrical newby's. ( regaurdless of the fact that a meter element may measure average voltage.... the display calibration is the issue.. )

(Neither a five dollar multimeter or a $100 root-mean-square voltmeter will provide the answer)

I never said it would. I use a quite expensive waveform reading o-scope style vom... not a 5$ unit.. or a 100$ unit.. more on line with lab grade equipment. It's the only way to get a good feeling for your power output. That way you can see peak / peaktopeak, and frequency, look at the sine wave, and looke dfor dropped or distorted waves, and look for noise harmonics.

If you are having problems with cheapy battery chargers.. look for triac based units. They can compensate fo undervoltage peaks by just leaving the 'on-time' a little longer. Triac based power supplies, for dc power generation are way tolerant of cruddy utility. Most good computer supplies can maintain 5v and 12v power rails ( at full current) with as little as 90v on the incoming ac line due to the way the triacs 'sample' the incoming wave.

(I was trying to avoid a lengthy technical and esoteric discussion. I was making a general statement considering this is not a forum for electrical engineers.)

You may be surprised to find out how many engineers are on ytmag.

Soundguy

For sine wave voltage relationships:

E max = Peak

.707 E max = RMS ( called Effective voltage )
1.414 E rms = E max

1.57 E average = Emax
.637 E max = E average

That's where my issue was. You were intermixing electrical and non electrical terms together.. specifically, the word "average" which as you can see, is actually .637 Peak...

Soundguy

Here it is again...:

(If an AC line is jumping back and forth with 170 volts at its peaks and
valleys, and your hand-held voltmeter is displaying 120 VAC, then it is providing an
average or composite reading)

Maybee something changed from when you took electronics till I took electronics.

If you have 170v peak.. then the RMS reading is 120.. That's not an average reading.. average is another figure.. .414 peak I believe..

My point was.. By you intermixing very specific technical terms like Peak, RMS and AVERAGE, and then mix them in with 'common' language as you say.. then the term "AVERAGE" is going to be confused.. just like it is now... with you using the term to mean 'composite' reading.. .. when in reality.. 'AVERAGE" is another power calculation, just like RMS is, pased on PEAK votlage... that's where the issue is. You are using a common term in a technical discussion that has the 'term'.. but has a different (specific) meaning tied to it. That's where the confision comes in.

Soundguy

As I read your post, and since you are alive to talk about it, I can imagine you doing pullups, and I can chuckle.

As a phone guy, I go into generating stations plenty. One time turns out my splice was under a 34KV vault that ran... out in a 138KV yard, behind a 34KV cable tray a foot above 3" of flowing water. The water table was higher than the bottom of that vault, and any given day of the year, there's 3" of flowing water in that vault, 24/7. I didn't care for that, so got a plant operator to take a look. He trudges through the water with a hand probe and starts...probing those cables. I didn't care for that either since an arc would've gotten us both, or I might've had to watch him explode. Man I wanted to climb out and run, but wasn't going to leave him down there by himself. He said "they're safe", and I didn't care for that either since I had to crawl over the tray to get to the splice, so we went back to the electrical maint shop and he grabbed several 17K rated mats, figuring that if he stacked them (17K + 17K +...), we'd be ok. Mmm, I still didin't care for that, but he stacked them and crawled over them himself. He was part of a pool that hit on the lottery and was getting $50K for the next 20 years on top of his scale for working. I thought about it a few and figured that under those conditions, no way he'd chance that, so I reluctantly climbed over too, and fixed my splice. Never tried that again, never will. A year or two later while leaving the plant, I saw a sign on the fence "In loving memory of our brother..." (wasn't him), and turned around and went back to ask about... He was up high in the plant working on... and the buss wasn't tagged or pulled and locked out several levels down below, and I don't need to tell you what happened. Mmm. Was a well experienced sparky with 20 or 25 years in that fossil, and friend and neighbor of mine. Accidents happen. No matter how safe one is or isn't, they sure do.

Mark

george

george

If you get the erge , come visit .

george

Dusty