Voltage Drop Case Study

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3. Case 2: Voltage Drop A customer bought a land that contains several houses with an automatic gates each. All of the automatic gates works fine except for one gate that often malfunction due to tripping of the internal overload. Although all the gates are made of the similar parts, circuit and gates, that one gate is the only one that causes problems. That one problematic gate has change almost every component (motor, gears, breaker, etc.) except for the feeder to the motor. The motor is a ½ horse power, 120V with integral overload protection and it is fed by 2 #8 AWG cables with length of 550ft each. (M.Stinnett, 2012) 3.1. Power Quality Disturbance involved A) Mechanical failure during the assembling of automatic gate (M.Stinnett, 2012)…show more content…
New voltage drop with 240v single phase transformer: Vdrop = (2 x Length x Resistance x I)/1000 Vdrop = (2x550ftx0.778x4.9A)/1000 = 4.19V 4.18V/240V = 1.7% voltage drop The result show that the voltage drop of the system is lower than the limit set by NEC, so it will not reach the limit of the voltage loss. Transformer is applicable in reducing the voltage drop for this system and solve the undersize overload circuit problem. 4. Difference between power quality…show more content…
For case 1 shows that it has cause high voltage spikes from the lightning strike onto the power transmission lines and causes failure to the distribution of power which resulted in blackouts throughout the involved cities. For case 2, the mechanical failure during the assembling of the automatic gate has causes a voltage drop to the motor and increased current drawn from the motor which then resulted in the malfunction of the motor. These types of disturbances are the causes of reducing the quality of the power distribution. However, in real-life events, there will never be an ideal case in electrical world. Therefore power quality will always be reduced not only from the common disturbance as listed but also power losses that could be caused by both nature and humans. Therefore, engineers comes up with ideas and solutions to overcome these problems. Based on case 1, engineers come up with TVSS to prevent the high voltage spikes to reach electrical equipment and Portable Motor Generator as temporary source to supply power in case of black out. For case 2, changing the cables to #4AWG or #8AWG cable will lower the chances of voltage drop according to the calculations
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