Under Voltage and Over Voltage Effect on Motor Explained


Under Voltage and Over Voltage Effect on Motor Explained



Hey, in this article we are going to discuss the under-voltage and overvoltage effects on motor. We will discuss how a motor reacts during voltage variations or voltage fluctuations or the effect of voltage variation on motor. Electric motors are a major part of electrical engineering and used everywhere. There are different types of motor available. High-capacity motors are so costly, and their breakdown may cause a huge loss of production, operation. So to properly maintain an electric motor we must aware that it getting proper supply voltage and current. At the same time, we have to look at the voltage variation and should take the required precautions, protective devices.


Under Voltage Effect on DC Motor


The working principle of the DC Motor is very straightforward. If the load on the motor is constant then the speed of the motor is directly proportional to the supply voltage. So when the supply voltage falls then the speed of the motor also be low. So during the under-voltage fault, the DC motor does got affect more. Of course, your mechanical load or the system connected to the motor will be affected. When the supply voltage suddenly falls the speed of the motor will suddenly fall down which can cause a big impact on the mechanical load.




Over Voltage Effect on DC Motor


DC Motor is a self-regulating machine due to its Back EMF Phenomenon. During the overvoltage fault, the DC motor does not affect more. When the supply voltage increase, the back emf on the motor also be increase. We know that the back emf on the DC motor always opposite to the supply voltage. So the back emf will oppose the flow of high current during overvoltage fault. Of course, if the supply voltage goes extremely high then the insulation of the motor coil will be damaged because insulation depends on voltage not current. 
Overvoltage causes the speed of the DC Motor high, so it may affect the mechanical load connected to the motor.




Effect of Voltage Variation or Fluctuation on DC Motor


Voltage variation or Voltage Fluctuation implies that the frequently falling and rising in supply voltage. Although DC motor does not get more electrically affected due to voltage fluctuation but it may damage mechanically. That means its brushes, commutator, bearing get damage quickly. Because during the voltage fluctuation, the speed of the DC motor also be fluctuated. Due to voltage fluctuation, the mechanical load connected to the motor will be affected.




Under Voltage Effect On Induction Motor(AC Motor)


An induction motor or AC motor works in a completely different principles than a DC Motor. An induction motor works on the principle of electromagnetic induction or same as a transformer or we can say induction motor is a rotating transformer whose primary winding static and secondary winding rotating part. Also, note that the secondary winding or rotor of the induction motor always closed circuited. So, same as the transformer principle, when voltage low current will be high, and when voltage high current will be low.

So, when the under-voltage fault occurs, the induction motor will draw a very high current, and due to the flow of high current the coils will be overheated and it will be burned.




Over Voltage Effect on Induction Motor(AC Motor)


Now, if over-voltage occurs across an induction motor, then the insulation of the winding will be damaged because we know that the insulation of any conductor or wire can withstand a certain limit of voltage. So when a high voltage applied the insulation will be damaged.

The overvoltage also causes to flow high current in the primary or stator coil of the induction motor which may cause the burning of the winding.




Effect of Voltage Fluctuation or Variation on Induction Motor


Voltage fluctuation does not affect so much the operation of an induction motor but frequently voltage fluctuation can damage any machine. Generally, electrical motors are connected through many protective, switching, and sensing devices so before the motor got affected, the circuit will be tripped.




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Under Voltage and Over Voltage Effect on Motor Explained Under Voltage and Over Voltage Effect on Motor Explained Reviewed by ETechnoG on 3/28/2021 Rating: 5
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