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what is the range of using dol starter & star delta
starter.
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Answer Posted / pawan
Till 5HP motors we use DOL starters . If we use beyond it,there will be a drip in the mains power supply.. Beyond 5HP, star delta is use as firstly motor operate in delta and thus its starting voltage is less(which is req. as in starting no back emf is there) after an instant it start operating in star as now motor has developed sufficient back emf to counter the voltage. Now the current is less(I/root3) as less current is beneficial reducing losses.. Now the ques. arises why only 5HP?Why not 5.2 or 5.5? The answer is its just a standard value.When it is tested beyond 5HP, drip is showing.. Thus the value 5HP.. Also motor are not available as 5.2 or 5.3 HP..So the standard value taken is 5HP...
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