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What does the metal oxide varistor MOV in the terminal block do?
The varistor is mainly used to perform as a line voltage surge suppressor. The device does not conduct when the voltage across it is below the clamping voltage. But, if a high surge (lighting) that is higher in rate that a varistor can handle is passed through it, the component will not perform.
How does varistor protect circuit?
Varistors are used to protect a circuit from high voltage surges. When a high voltage surge is applied to a circuit, the outcome is usually catastrophic to the circuit. When a voltage surge exceeding a specified voltage (varistor voltage) is applied, the varistor suppresses the voltage to protect the circuit.
How to calculate peak transient current in varistor?
Calculate the peak transient current or the surge current through the varistor. You should select the varistor that has the surge current rating equal or slightly greater than the current rating required by an event that the circuit may produce to make sure it functions properly.
How does a metal oxide varistor ( MOV ) work?
What is a MOV (Metal Oxide Varistor)? MOV is simply a variable resistor, but unlike potentiometers, MOVs can change its resistance based on the applied voltage. If the voltage across it increases the resistance decreases and vice versa.
How is the energy expressed in a varistor?
The Energy is usually expressed in standard transient x/y where x is the transient rise and y is the time to reach its half peak value. Response Time: It is the time at which the varistor starts conducting after the occurrence of the surge, in many instances, there isn’t an exact response time.
What is the maximum working voltage of a MOV?
Maximum Working Voltage: It is the steady-state DC voltage to which the typical leakage current will be less than the specified value. Clamping voltage: It is the voltage at which the MOV starts to conduct and dissipate the surge current.