Re: Voltage
Reply #33 –
This post provides additional information to that provided by J. D. Stevens, who got me started with his post.
Thank you Mr Stevens.
THE POWERTECH MANUAL INDICATES:
The generator may be wired at the terminal board to deliver either:
120/240 volts to a three wire distribution system, or
120 volts to a two wire distribution system.
INFORMATION ON: 120/240 - three wire distribution with two hots (red & black wires) and one neutral (white wire)
If any equipment requires 240-volts, then the 120/240-volt connection must be used.
Although the 120/240-volt connection may also be used when all loads require only 120 volts, this is not recommended.
The Electronic Voltage Regulator (EVR), will hold the voltage very close to 240 volts. When the two hot lines are evenly loaded, they will both be close to 120 volts, however, when the two hots are unevenly loaded, the heavily loaded line will have low voltage (ie 90 volts) while the lightly loaded line will have high voltage (ie 150 volts). The total voltage between the two hots will be regulated to 240 volts, but.....
INFORMATION ON: 120 - two wire distribution system with one hot (red or black) and one neutral (white).
If all equipment requires 120-volts then this is preferred because the two generator hot outputs are shorted together at the generator such that they each provides exactly half of the amperage demanded. This enables the Electronic Voltage Regulator (EVR), to hold the voltage very close to 120 volts on both hots, regardless of the power distribution amoung the different distribution lines.
WYATT'S RAMBLINGS:
The 120 - two wire seems confusing because the wiring on my Foretravel from the generator to the panel is a three wire distribution with two hots and one neutral. In reality, while there are two hot wires, a red and a black, these wires are shunted (shorted together) at the generator, such that the two hots from the generator each provide exactly the same amperage (perfect balance). Note that the "red hot" and "black hot" wires from the generator to the panel will not carry the same amperage, but will have the same voltage.
It seems that Foretravel has provided the three wire distribution from the generator to the panel such that folks needing 240 volts can just simply rewire at the generator. Unfortunately, Foretravel only provided 50 amp neutral wiring from generator to panel, while 100 amp neutral wiring is required. In a previous post, damage caused by overloaded neutral wiring was eluded to. I now understand why the neutral generator contacts in the automatic tranfer switch, which I replaced with 65 amp manual switches, was discoloured from overheating (this is frightening to me).
The solution recommended in a previous post is to not exceed 50 amps, which means I carry around a 700 pound, 10KWatt generator but can only safely use 6 kilowatts.
I believe, for most folks, a good solution is to run another #6 neutral wire from the generator to the transfer switch and on to the panel after installing a 100 amp transfer switch.
Another solution is to convert the generator output to 120/240 and load balance. Install another power watch voltmeter so you can see the voltage on each hot line. Load balancing could include: run both a/C units not just one, use two electric ceramic heaters with one on each hot, assure that the electric hot water heater is not on the same hot as the microwave. Foretravel has done a reasonable job of load balancing between the two hot lines and I believe this could be preferred to an overloaded neutral line. However, I have no idea how much unbalanced load can be tolerated, ie 10 amps or 30 amps! Does anyone know?
Other solutions, would be to put a fuse in the generator neutral wire, or replace the 10K generator with a lighter 6K generator.
FWIW
Topic: Voltage