We all know that a Direct on Line (DOL) starter will supply full voltage to the motor at the supply frequency with the current uncontrollable. The motor will use as much current as the load requires normally between 600 to 700% of the full load current of the motor. Before the days of Soft Starters and frequency inverters, our alternative to control the starting current was with Star Delta starters, which reduced the starting current to approximately 200%.
Our next best device today to limit the starting current is to fit a Soft Starter, With Soft Starters we use the Phase Angle principal to control the voltage and therefore reduce the starting current while at the same time producing a smooth controllable start.
There are 3 distinct types of solar energy inverters, each of which serve a different function and are used for a different type of solar energy system, although each inverter still converts DC into AC:
- Stand Alone Inverters
- Grid tie Inverters
- Dual Inverters
Stand-alone inverters: These are used for off-grid solar arrays. In off-grid arrays, the solar panels generate direct current energy which is then stored in rechargeable batteries. When energy is required, the direct current is sent from the battery to the stand alone inverter and then converted into alternating current which can then be used to power a home or for any other electricity needs.
Stand-alone inverters can also charge laptops, cell phones, water pumps, and even to charge car batteries.These inverters are necessary for locations where no local power grid is available, or for anyone who wishes to remain completely independent of energy companies.
With a standalone system, you will be unaffected by power outages because your system will be completely independent from the power grid. You will be free to consume electricity whenever you wish, provided your batteries are charged or your solar array is currently producing electricity.
Grid-Tie Inverter: It is a power inverter that converts direct current (DC) electricityinto alternating current (AC) with an ability to synchronize to interface with a utility line. Its applications are converting DC sources such as solar panels or small wind turbines into AC for tying with the grid.
Dual inverters: Also known as Backup Battery Inverters and are used in a multi-function solar system. In this system, the direct current generated by the solar panels is first sent directly to a battery.
The energy from the batteries is then sent to the inverter and converted to alternating current whenever electricity is required. However, when the batteries are fully charged, any excess direct current electricity that is generated is sent directly to the inverter and is then sent into the local power grid. This system combines the other two systems into one self-reliant and possibly money generating solar unit.