joeyww12000
Senior Member
- Location
- Chatsworth GA
Can someone give me a website where I can see and understand 3 phase motors and how a 240v receptacle works?
3 phase motors and 240v receptacles
- Thread starter joeyww12000
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Start here at Wikkipedia and see if that doesn't confuse you some more.
3 phase power.
Not sure what you mean by 'how a 240v receptacle works.' Receptacles don't do work. They simply provide a connection between the building wiring and a cord plug.
Not sure what you mean by 'how a 240v receptacle works.' Receptacles don't do work. They simply provide a connection between the building wiring and a cord plug.
joeyww12000
Senior Member
- Location
- Chatsworth GA
what i meant is how two different phases provide current to operate a piece of equipment without a neutral?
winnie
Senior Member
- Location
- Springfield, MA, USA
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- Electric motor research
For the moment, forget about the term 'neutral'.
To deliver power to a load, you need wires connected to a minimum of _two_ transformer terminals from a single transformer or set of connected transformer. The alternating current flows back and forth between these terminals, over the wires, to the load.
In conventional single phase 120/240V service, it turns out that you have a transformer with three terminals. The voltage between the two end terminals and the 'center tap' is 120V; the voltage between the two end terminals is 240V. Pick any two terminals, run your wires to a load, and you have a closed circuit with current passing through the load.
You can add more transformer coils, more terminals, and run more than the minimum of two conductors; thus you could run three conductors to a 120/240V load, or build a three phase system. But the minimum remains two conductors between any of the two terminals.
'Neutral' is simply a name that gets applied to one of these terminals. When selecting your pair of terminals to supply the load, it is not necessary.
-Jon
To deliver power to a load, you need wires connected to a minimum of _two_ transformer terminals from a single transformer or set of connected transformer. The alternating current flows back and forth between these terminals, over the wires, to the load.
In conventional single phase 120/240V service, it turns out that you have a transformer with three terminals. The voltage between the two end terminals and the 'center tap' is 120V; the voltage between the two end terminals is 240V. Pick any two terminals, run your wires to a load, and you have a closed circuit with current passing through the load.
You can add more transformer coils, more terminals, and run more than the minimum of two conductors; thus you could run three conductors to a 120/240V load, or build a three phase system. But the minimum remains two conductors between any of the two terminals.
'Neutral' is simply a name that gets applied to one of these terminals. When selecting your pair of terminals to supply the load, it is not necessary.
-Jon
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
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- Electrical Contractor
Joey, see if this helps: http://forums.mikeholt.com/showpost.php?p=708650&postcount=4joeyww12000 said:
K8MHZ
Senior Member
- Occupation
- Electrician
joeyww12000 said:
If you are referring to 120/240 residential services, you only have one phase. The difference in voltages comes from the single phase transformer being tapped in three separate places. Kind of like putting 2 flashlight batteries (cells) in series. From one end to the other you will have 3 volts. From either end to the center you will have 1.5 volts.
If you connected identical 1.5 volt light bulbs in series across the ends, the volts would be distributed equally and 1.5 volts would drop across each bulb and no connection to the center would be needed. If you remove one bulb in order to get 1.5 volts to the bulb you would need a connection to the center. If you place bulbs of different resistance in series with no center connection, one would get more than 1.5 volts and the other would get less. That's because in a series circuit, the amperage stays the same and the voltage drop changes. If you were to then make a connection from the center of the pair of cells to the center of the pair of bulbs, you would now have a parallel connection and the voltage would be the same across both bulbs and the current would vary.
The same is true with an AC transformer. The best way to visualize the phenomena is to actually do the battery / bulb experiment outlined above. Sometimes the written word, no matter how articulate, does not suffice as an adequate explanation.
Especially when it comes to electricity.
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