But, that doesnât mean students have to take them all in the same week. Our class structure allows us to provide 5 cycles of classes for every 30-day period. As long as students take the classes in order, (Class 1, Class 2, Class 3, Class 4), they are free to switch between any of the cycles for that 30-day period. The only other requirement is that all 4 classes must be completed within 30 days of the first class.
Re: Advantages of three phase systems over single phase. The big advantage with 3 phase mains is that any electric motor connected to it is more efficient, has smother running and uses less parts so is more reliable. There is also a slight advantage in using 3 phase transformers over single phase ones.
Generally speaking, single phase. is used on electric motors that are less than 1 horsepower. Motors 1 horsepower and larger. should be supplied with three phase power if it is available. Generally available power supply voltages for single phase are 120 volt and 240 volt.