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Generator set up ideas wanted
Interesting discussion, however I’m having trouble sorting out the various positions that folks are taking … maybe it doesn’t matter.
However it is a fact that in order for electrons to flow there needs to be a path. And sometimes humans are in the path and bad things happen.
Consider this, birds, squirrels and other little varmints climb power poles and sit on high voltage lines all the time. But as long as the impedance between them and the second conductor is high enough nothing bad happens. The key here is that the total circuit impedance between the animal sitting on the conductor at point A relative to a point B of the second conductor remain relatively high. If the magnitude of this impedance drops low enough such that a few ma’s were to cross the little buggers heart he may be toast.
So Murf, what exactly is your claim?
Are you claiming that there is a circuit path of consequence given the fact that one has disconnected the high side power but left a connection between the gnd/neut system of the house and generator? Or are you merely arguing that a potential exists between the house and the public feed, i.e., service transformer?
It would be helpful if you would provide a schematic to help illustrate your point. Something similar to the one in the link that Ann provided is adequate.
Dave
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Generator set up ideas wanted
It’s clear that there’s a lot of mysticism in the minds of folks when it comes to electricity.
The point to keep in mind is that any source, be it a AC, DC, Pulse, RF or some Arab Gen requires an output port and a return port in order for the electrons to move.
As Ann has pointed out, disconnect the Generator at the high side or low side and it’s out of the circuit. Think of your battery, both the positive lead and the gnd lead have to be connected in order for energy to be delivered.
I’m not a big code guy myself, but there is a subtle but important point that is being made, I think in sch 3 or 4. And that is, if the return for the gen is left connected to the main house circuit while the house is being powered by the public utility, the current path has the potential to be shared by the return path through the generator. In order for this to happen one would have to have the return path of the load connected to the generator while the high side is open. Why a system would be put together to allow this to happen is beyond me, but I guess it’s certainly a possibility. Mind you, the potential problem is localized to the home.
At any rate I view codes as an attempt at protecting the masses from themselves. It’s a shame, but the reality is you need some standardization because of all the unscrupulous vendors trying to take advantage of folks.
For those that are interested here’s a poor mans way of dealing with the alternative power issue, albeit not automatic and definitely not preferred by the wife.
I live in the northwest among big trees where occasional big winds or snow storms knock out the power.
I have a 10K generator that I use to power some essential stuff like the well pump, pellet stove, frig and a few lights. I don't use a transfer switch but have chosen to treat the loads as appliances. For example, the well pump is on a breaker of it’s own --- I simply break the connection between the pump and breaker, mount a 30 amp receptacle on the output side of the breaker and place a plug on the input side to the pump. (My access panel is in the garage … makes it easy to do).
I have separate outlets for the rest of the items. And yes it’s a little work to go out and start the generator, move four or five plugs but it works and is safe.
In my situation installing an automatic transfer switch for this small of a generator is just not worth the effort and cost.
One of these days I’ll get around to putting in a large diesel or propane generator and automatic transfer switch system --- it’ll make the wife happy.
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Generator set up ideas wanted
Carldarnell,
Consider yourself one fortunate soul ---
I tried to look up your serial # on the Smith motor but with no luck --- it's pretty old.
As you stated, in order to change the shaft rotational direction of an AC motor the field connection of the stator windings relative to the armature must be interchanged.
Having said that, I guess it is possible that older motors could have one side of the stator or armature tied to the frame. In that case it still should be possible to maintain the frame as the return while changing the rotational direction provided these operational details were understood.
With modern commercial motors there is no connection to the frame by design, (at least that I’m aware of).
Personally I'd get rid of the motor --- motors are pretty cheap these days. I personally wouldn't want a device with the frame tied to either the "hot" or "return" legs.
Secondly there is no "two" phase system in use in the US, (sin and cos with a phase shift of 90 deg).
Public power is either a 3 phase system, (120 deg) or a single phase transformer driven from one leg of the 3 phase system relative to the system neutral. The output of the transformer is typically 220 with a center tap --- but it is still single phase. Of course the output taps on either side of the center tap are 180 deg out of phase relative to each other --- think of your wall-wart.
I do hope your rethink your plan to use that motor. Just not worth the risk of potential injury in my opinion.
jdcman
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