There is no single 3-phase voltage that answers this question. Just as you have three different phase to neutral readings, you will have three different phase to phase readings.
Voltages used to described a power distribution system are 'nominal' values. For instance, the battery in my auto is a '12 volt' battery, yet fully charged it measures more like 13.6 volts, and that number changes with load and state of charge. We still call it a 12V battery. The nominal system voltage in your question would be the 230/400V 50Hz system used in Europe. We would measure about 230V phase to neutral, and about400V phase to phase. The individual phases could vary according to load conditions and transformer taps, but we would still use the nominal numbers when describing this system.
Since your question is in the singular, the answer would have to be the nominal system voltage of 400. The formula is:
single phase voltage * 1.73 = phase to phase voltage (nominal)
If you really meant the exact voltage on each possible phase pair, then easiest will be to measure it. If you really want to mathematically calculate the phase to phase voltages given three unbalanced phase to neutral values, that is a pretty advanced subject I will leave to the next answerer!
formals to calculate exciation voltage of alternator
To calculate an answer a voltage must be stated.
when reading voltage at the meter base where power comes in the house.
Regulation =(Obtained voltage per phase - rated voltage per phase)/rated voltage per phase *100
Because the meter is connected backwards
If two phase voltages are the same voltage and the same phase angle, the the resultant voltage will be twice the voltage.
The voltages appearing across each branch of a parallel circuit will be equal to the supply voltage.
The unit of resistance is the Ohm, and by applying a small voltage to your wire, and measuring the resultant current, you may calculate the resistance.From the formula I = E/R, where R = resistance in Ohms, E is the voltage in volts, and I is the current in amperes.
you calculate a voltage circuit by taking it apart and findng the circuit and calculate the voltage and then resible it.
formals to calculate exciation voltage of alternator
Voltage drop is resultant of IR ie current and the line resistance, not dependent on impressed emf
Secondary voltage / primary voltage
To calculate an answer a voltage must be stated.
Since the alternators are in parallel, the resultant voltage should be the same as either alternator - exactly as it would be if two batteries are connected in parallel. Voltage remains the same but current capacity is doubled. I would recommend connecting the alternators through a network that will balance the load between them.
How do you calculate voltage drop for starting motor current
no load voltage - full load voltage by full load voltage
V = I x R V = voltage, I = Current, R = Resistance or it can be calculate like this V = P / I V = Voltage, P = Electric Power, I = Current