Author Topic: 115 or 220  (Read 12358 times)

jzeeff

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Re: 115 or 220
« Reply #15 on: December 12, 2007, 03:58:44 AM »

So a secondary flywheel would help smooth things out?

Doug

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Re: 115 or 220
« Reply #16 on: December 12, 2007, 04:08:11 AM »
Yes, adding mass will store energy so that between power strokes the alternator won;t so downas much and durringht epower strocke won't accelerate as hard.

Anything you do to keep the shaft speed will reduce voltage and frequency changes and Flicker.
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Stan

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Re: 115 or 220
« Reply #17 on: December 12, 2007, 05:15:35 AM »
Jzeeff...that's why the SOM's which were primary producers of electricity have flywheels that weigh 275 lbs each as compared with regular Lister 6/1 flywheels that weigh only 143 lbs each.  As well, the generator on the SOM's had a large pulley that added even more weight.

I just moved the base, crank and flywheel assembly of my SOM type 6/1 90 feet from it's "parking spot" into my garage by hand.  I figure flywheels 550lbs, crank 90 lbs plus base 200 (?) lbs equals 840 lbs.  Its a good thing my species had people like Archimedes and his lever and some nameless Mesapotamian who invented the wheel etc. etc.  It's sitting on a frame which is sitting on 4 casters now (don't even ask how I got it up 8 " in the air to put it on the frame) that are rated at 200 lbs each.  The solid rubber wheels are starting to flatten on the bottom  ???  (must be chinese casters)
Stan

Quinnf

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Re: 115 or 220
« Reply #18 on: December 12, 2007, 08:05:46 PM »
Zack,

That's an interesting question, and one that the Wiki articles don't address.  Wonder if it could it be that there is more persistence in the phosphors in the CF bulb.  I notice when you turn off a CF light in a dark room, there is some persistence, whereas a standard cool-white fluorescent tube shuts off, like, right now. 

Quinn
« Last Edit: December 12, 2007, 08:07:43 PM by Quinnf »
Ashwamegh 6/1, PowerSolutions 6/1 "Kit" engine, and a Changfa R175a that looks like a Yanmar I once knew

Doug

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Re: 115 or 220
« Reply #19 on: December 12, 2007, 08:42:56 PM »
Electronic ballast Quin:

The high switching speed is not dependent on the line frequency so as long there is enough power to charge the caps inside and do what ever else all the bits in there are doing it will more or less behave as it would on grid power.

I don't know why the coating continues to glow after the power is off on some, its a very interesting question. I have noticed the pink tint to bulbs that are past their prime, now I know its because the Mercury inside is exhausted....

Wiki articles are getting better, used to be easy to spot errors now its too the point you can start to trust it as fairly reliable.

Doug
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Quinnf

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Re: 115 or 220
« Reply #20 on: December 13, 2007, 12:56:00 AM »
Right.  There is both a frequency fluctuation and a corresponding voltage fluctuation.  The voltage fluctuation is responsible for the flicker.  But that voltage fluctuates periodically at the frequency I mentioned.  Mebbe I didn't state that very clearly.

A lot of people used to complain of fatigue when reading under fluorescent lights (the traditional type).  It might be that some persistence in the phosphors was part of the design of CF lights.  In shop class I was taught that it was bad practice to light a shop with fluorescent light because the strobe effect can, under just the right conditions, make piece of rotating machinery appear to stop.   

Oh here it is in Wikipedia: 

Flicker problems

Fluorescent fittings using a magnetic mains frequency ballast do not give out a steady light; instead, they flicker (fluctuate in intensity) at twice the supply frequency. While this is not easily discernible by the human eye, it can cause a strobe effect posing a safety hazard in a workshop for example, where something spinning at just the right speed may appear stationary if illuminated solely by a fluorescent lamp. It also causes problems for video recording as there can be a 'beat effect' between the periodic reading of a camera's sensor and the fluctuations in intensity of the fluorescent lamp.

Incandescent lamps, due to the thermal inertia of their element, fluctuate to a lesser extent. This is also less of a problem with compact fluorescents, since they multiply the line frequency to levels that are not visible. Installations can reduce the stroboscope effect by using lead-lag ballasts, by operating the lamps on different phases of a polyphase power supply, or by use of electronic ballasts.

Electronic ballasts do not produce light flicker, since the phosphor persistence is longer than a half cycle of the higher operation frequency.

The non-visible 100–120 Hz flicker from fluorescent tubes powered by magnetic ballasts is associated with headaches and eyestrain. Individuals with high flicker fusion threshold are particularly affected by magnetic ballasts: their EEG alpha waves are markedly attenuated and they perform office tasks with greater speed and decreased accuracy. The problems are not observed with electronic ballasts.[3] Ordinary people have better reading performance using high-frequency (20–60 kHz) electronic ballasts than magnetic ballasts.[4]

The flicker of fluorescent lamps, even with magnetic ballasts, is so rapid that it is unlikely to present a hazard to individuals with epilepsy.[5] Early studies suspected a relationship between the flickering of fluorescent lamps with magnetic ballasts and repetitive movement in autistic children.[6] However, these studies had interpretive problems[7] and have not been replicated.


http://en.wikipedia.org/wiki/Fluorescent_lamp

Ok, so the operating frequency of CFs is higher than regular fluorescents.

Learn something new every day.

Quinn

« Last Edit: December 13, 2007, 01:24:07 AM by Quinnf »
Ashwamegh 6/1, PowerSolutions 6/1 "Kit" engine, and a Changfa R175a that looks like a Yanmar I once knew

Doug

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Re: 115 or 220
« Reply #21 on: December 13, 2007, 01:36:31 AM »
Not all of them have an electronic ballast.
I have a few boxes of ballasts and bulbs that are old inductive core not electronic and they have the same 120 hz flicker that any other common light like an F40 has.

These days you walk into an big shop with high bay lights and you find its lit with HID lights any way no one realy notices. One way around this strobe effect is to lay your bay lighting out so you have all three phases running lenght wise in the shop.

Doug
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dno

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Re: 115 or 220
« Reply #22 on: December 20, 2007, 01:03:42 AM »
Hi all, my first post here. Back to 115 or 220?, or on my st, 120/240. I too would like to wire it parallel for 120v only
so all current is available for loads without balancing problems. However, if I understand correctly how these heads work,
wired this way you will have two hot leads at half or 60v RMS, each 180 deg out of phase, giving 120v total. Same as
when wired in series two ends of windings are hot but voltage adds and you get 240v total.
Am I correct so far?
If so, then is set up would not be useful if using a transfer switch/to load center, but only as a stand alone power source
with direct wiring (extension cord) to loads right?
I've never seen this point about the output explained and I want to be sure I understand it.
dno

trigzy

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Re: 115 or 220
« Reply #23 on: December 21, 2007, 04:12:55 AM »
dno,
     In a word; no.   

Right now, the windings in your ST head are in series;

[ --- --- ----- ---- 240V ---- ---- --- ---]
120                NEUT               120
(-Winding 1 +)-------(-Winding 2 +)

You need to cut that connection, and wire them in parallel


|(-Winding 1+)|
|                   |
|                   |
|(-Winding 2+)|
120              NEUT

(Note the +/- just indicate the polarity, it's not meant to imply that they are DC.

George has some article at utterpower on how to do this if it isn't already the wires needed in the junction box.

Steve

Power Anand 24/2, Brushless 20kW, some other antique iron.
Vendor of AVR's, Small Clones of Yanmar Diesel and Honda Gasoline Engines

dno

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Re: 115 or 220
« Reply #24 on: December 22, 2007, 01:48:21 PM »
Steve,Thanks. I know how to wire it, but I'm looking at the connection to the house distribution center.
I thought I had a decent grasp on AC and DC but now I'm not sure. Back to the books!
I always treated neutral as 0v or potential at the panel since it is bonded to ground, and the hot! leads as
alternating +/-v sine wave. Volts push current so current direction alternates (AC). I'm not sure I've got this relationship
correct. I may also be mistaken about voltage/current induced in a coil/winding. I may have misunderstood
the +/- convention that is used to show current direction at a point in time, and thought voltage induced
in a coil went positive at one end and negative at the other then reversed respective to the n/s poles they were passing.
I also thought (?) the midpoint or center tap on a winding was neutral and steady 0v because the opposing voltages +/- at
the ends canceled (neutralized) each other at that mid point.
I'm self educated in this and many things, and the only thing I'm sure of is that I may be wrong in my understanding
at times and thats when I learn.
When Jonny started this tread he mentioned that his power tool sounded like it was getting real power!
I did wire my test set up for 120v parallel  and thought my saw also started and ran differently (better).
This led me to believe the power was different some how, from the ends of the winding, than the series
set up with power from one end and the center tap neutral.
I'll have to do some testing and reading but for now I'm off to weld up a heat exchanger.
later,
dan (dno)   

johnny williams

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Re: 115 or 220
« Reply #25 on: December 22, 2007, 02:14:04 PM »
If I understand correctly(?). Just for example your gen head is putting out 20 amps @120  VAC when upu woire the head to put out 220 VAC you have doubled you voltage (potential) but halved your amperage (pressure), sorry it's the plumber coming out in me, to 10 amps per leg. Therefore you only have the 10 amps available for starting a 120V load instead of 20amps. Am I correct or just over simplyfing it for my simple mind.

oliver90owner

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Re: 115 or 220
« Reply #26 on: December 22, 2007, 03:18:02 PM »
If that is plumbing, you had better watch the flow.  Current equates to flow in the analogy, pressure is the potential.

The load will be in Watts, Joules per Second.  Watts is the product of current in Amps and potential in Volts.

You are correct in your thinking that you only have half the output current available except that now you have half the current at twice the voltage so same power.  120 volt load might not like that?
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Regards, RAB

trigzy

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Re: 115 or 220
« Reply #27 on: December 22, 2007, 04:33:44 PM »
DNO,
      Your power tool might run better because it has twice the starting current available.  Other than that, the power is the same.

If you are only running 120V loads on a standard house panel, you can wire the coils in the generator in parallel, and then attach one end of the coils to the netural bar, and the other to both hot bars.  Any 240V loads will not work.  I have a seen a 240V load (a stove) that had a center tapped transformer in it for the controls (ie. it was hooked up to both 120 legs, and the netural), and acutally popped the fuse on this, so maybe best to open any 240V breakers.  Also, any split receptacles (120V outlet on a 2240V breaker) could have thier neutral lines overloaded, so just best to shut off all double pole breakers.

As for the conventions we use, they do represent the coil at one point in time, simply so we dont wire the coils in a dead short configuration.  The best way to play with this, I think, is to get two D- cell batteries, and experiment with them in series in and parallel.  Cover up the +/- symbols on your meter, and the result on the meter will look just like the AC readings would.  One thing you can learn from this, is that neutral or ground is only where YOU choose it to be, you can place the - lead anywhere, and that BECOMES your ground, and you can reverse your +/- leads, and you still get the same reading.  If you put one meter lead in the middle of the batteries in series, you will get two legs of 1.5V each, if you measure across the two legs, you get 3.0V, just like our edison wiring system.  And you can turn both batteries around, and is still works the same.

Steve
Power Anand 24/2, Brushless 20kW, some other antique iron.
Vendor of AVR's, Small Clones of Yanmar Diesel and Honda Gasoline Engines