You set a current threshold - it can be different for each of the 2 AC inputs.
Imagine a generator starting a compressor or some motor load. Before the load is applied, the generator is running fine at 120 volts. A huge load is suddenly applied (ac compressor, gas dryer motor, etc.) For a short time 30A is required, but the gen can only supply a max of 22 amps. The gen will bog down trying to service this load and the voltage will drop. Without help, it may or may not recover. The inverter supplies current, but it does not raise the voltage. The generator no longer has to service the large current draw, so the generator voltage will rise and the inverter will see the voltage back over some threshold and stop providing input current.
I think
this is from a Magnum employee:
GBaxter wrote:
All the MS and MSH model sync with the incoming ac waveform before they transfer to make sure the loads stay on the same phase during transfer and will stay synced until they hit the low voltage dropout setting.
The way all the MSH models load support is by monitoring ac input current. When the shore (or grid input) amp setting is reached the inverter will automatically start to pull current from the batteries and add to the input current. In some cases it may help hold up the voltage depending on the source. If the source is grid then there is no way a 4kw inverter and some batteries are going to raise the voltage on the whole grid, if it could we wouldn't need substations on the grid.
If the source is a small generator then it may help stabilize the voltage but remember the inverter is always synced to the incoming waveform and it will try to follow that waveform as long as it stays connected. The way it can help a generator and the way the Trace SW series helped (it could not raise the voltage either) was it will load support and try to take some load off the generator in hopes the generator can pick up its voltage running less load.
The MSH will continue to Load Support until it reaches .5 VDC above the inverter Low Battery Cutout setting. It will then return to charge mode to bring the batteries up to charge.
I hope this helps,
Gary
