The sizing of Transformers is based on an accumulation of all of the loads that will be connected to it. Add up all of your loads and possible loads in the future and then tell your installer the figures and they will use these to calculate the size of the transformer that is needed.
You need a step up transformer unfortunately. Buy an Ugly's book electrical reference book. They're great and there is a transformer chart in there that will list the proper size or Kva that you will need according to your amperage need.
There must be a 'return' connection if the load is to work. So, you cannot simply connect the load to the line conductor and expect it to work. It must also be connected to the neutral. In some circumstances (e.g. with no ground-fault interrupter installed), it will also work if you connect it to earth (ground) instead of the neutral, but this will contravene most electrical regulations and should NEVER be done.
First off, I'm going to have to quore Robert here: (LIFE SAFETY WARNING! [disclaimer] Electricity is dangerous! You can be injured or killed! Improper installations can cause fire, injury and death! Should you be doing this yourself?) This is one of those questions - if you know this little, you shouldn't be doing what you are planning... No disrespect intended, but this is SO basic that it suggests you have not studied the subject at all! There are many good reference books and course books to study from. Unless you have 208V 3 phase power, you cannot make this work. You cannot power a 208V motor off a 120V supply. Since it is 208V, it is likely that it is a 3 phase motor. That means it has 3 hots. Check the specification plate on the motor, it should say how to wire it. With 208V 3 phase you should be able to get 120 from 1 hot phase to neutral. This means you need 5 feed wires (3 hots, a neutral, and ground) from your panel to your little light/motor contraption. Please buy a book and read up on this. It sounds like you don't know much about your system and ignorance is fatal (and not necessairly fatal to you) with electricity.
A single phase 600 to 240 Volt transformer using two phases of the three phase primary.
By design are you going to wind the transformer yourself? In your design you need a 5:1 ratio. On the output side of the transformer any two legs of a three phase transformer is considered single phase voltage. Good luck on your project.
Not directly, you would need to transform 480v circuit to 120v with a transformer first.
If the 240V 3-phase service is 240V phase-to-phase, then you can get 240V single-phase by simply picking two phases (poles, as used in the question) and connecting the load across them. This is simply one third of a standard delta connection. If you need 120V/240V split phase, i.e. with a neutral, as used in residential services, you will need a transformer. If the service is actually a four wire "quadraplex" service, however, you will probably already have that 120V/240V with neutral connection phase available. In this case, you will need to pick the two phases correctly in order to get the proper 120V service half.
You need a step up transformer unfortunately. Buy an Ugly's book electrical reference book. They're great and there is a transformer chart in there that will list the proper size or Kva that you will need according to your amperage need.
There must be a 'return' connection if the load is to work. So, you cannot simply connect the load to the line conductor and expect it to work. It must also be connected to the neutral. In some circumstances (e.g. with no ground-fault interrupter installed), it will also work if you connect it to earth (ground) instead of the neutral, but this will contravene most electrical regulations and should NEVER be done.
I think I understand what you are asking. 3-phase motors usually are equipped with a starter or contactor, since all 3 hot wires need to be switched. The control voltage that runs the starters is 120V, because it's safer and also 120V switches and relays are cheaper. You would have a 480-120V transformer (called a control transformer) in the starter box to provide the 120V "control voltage". So the arrangement you describe would have two contactors, with two phases reversed between them. Energize one, and the motor runs forward. Energize the other, and it runs reverse. The switch sends 120V to each of the contactors, which are equipped with 120V coils.
Harmonics are really not needed in single phase transformers.
A single phase 600 to 240 Volt transformer using two phases of the three phase primary.
First off, I'm going to have to quore Robert here: (LIFE SAFETY WARNING! [disclaimer] Electricity is dangerous! You can be injured or killed! Improper installations can cause fire, injury and death! Should you be doing this yourself?) This is one of those questions - if you know this little, you shouldn't be doing what you are planning... No disrespect intended, but this is SO basic that it suggests you have not studied the subject at all! There are many good reference books and course books to study from. Unless you have 208V 3 phase power, you cannot make this work. You cannot power a 208V motor off a 120V supply. Since it is 208V, it is likely that it is a 3 phase motor. That means it has 3 hots. Check the specification plate on the motor, it should say how to wire it. With 208V 3 phase you should be able to get 120 from 1 hot phase to neutral. This means you need 5 feed wires (3 hots, a neutral, and ground) from your panel to your little light/motor contraption. Please buy a book and read up on this. It sounds like you don't know much about your system and ignorance is fatal (and not necessairly fatal to you) with electricity.
Because they are "in-phase". In order to get 240v, you need two 120v Alternating Current lines that are 180° out of phase, that is, opposite phases. Only when one line is +120v and the other -120v will you see 240v between the wires.
By design are you going to wind the transformer yourself? In your design you need a 5:1 ratio. On the output side of the transformer any two legs of a three phase transformer is considered single phase voltage. Good luck on your project.
The basic difference is the secondary voltages. On a distribution transformer the secondary voltage is very high. This is to overcome line loss for transmission of electricity over long distances. A three phase power transformer is used at the consumers three phase services end to manipulate voltages that consumers need to operate their equipment. The transformer that feeds your house is considered to be a single phase power transformer.
In 120/208V 3 phase system you have 5 wires: three hots, one neutral, and one ground. You have 208V between any two hots and 120V between any hot and neutral. The neutral is the same as in a single phase system. Clarification: Only 4 wires maximum come from the pole - 3 phases and a neutral, and then only if the transformers are on the pole. The ground is always locally derived from a ground rod(s) and/or cold water pipe ground. Most of the time, only 3 wires come in from the pole - the 3 phases in a Delta configuration (Delta has no neutral). The neutral is then derived from a local transformer connected in a Delta-Wye setup. The neutral is the center connection in the Wye. So, from the utility feeder to the transformer - 3 wires. From the transformer (wherever it is located) to the building service entrance panel - 4 wires. The ground is connected at the service entrance panel, and from there to the rest of the building you would have all 5 wires. Clear? In the US, 208/120 is a standardized mains voltage, but in some parts of the world, the phase-to-phase voltage is 220. In that case, the phase-to-neutral potential (in a 3-phase system) would be 127 Volts, not 120.