What is MOV in surge protection?
A Metal Oxide Varistor (MOV) is a voltage dependent resistor. In other words, it’s an electrical component whose resistance varies with voltage. They are used to protect vulnerable circuit components from short surges of electrical energy.
What is MOV clamping voltage?
Clamping voltage: It is the voltage at which the MOV starts to conduct and dissipate the surge current. Energy Absorption: The maximum amount of energy that the MOV can dissipate for a specified peak pulse time of a specific waveform during a surge.
How do I choose a MOV voltage?
Application Guidelines
- Step 1: To find the voltage rating of the MOV, allow for 20% headroom to account for voltage swell and power-supply tolerances: 24 V dc × 1.2 = 28.8 V dc.
- Step 2: To determine which MOV disc size to use, first identify the MOV series that minimally meet the 1000-A surge requirement.
How are pluggable MOVs used for surge suppression?
For Pluggable Type A equipment, the most common solution for preventing the MOV leakage current from becoming an electric shock hazard is to place GDT in series with the MOV. A GDT has almost no leakage current until the applied voltage gets close to the GDT turn-on voltage.
How are surge currents affected by a MOV?
Rather, the conducted current increases exponentially as the applied voltage increases, and decreases as the applied voltage is reduced. Figure 1 shows some representative MOVs. Another common surge suppression component that can survive very high surge currents is the gas discharge tube (GDT).
What should MOV value be for surge arrester?
To stop the arrester from responding during normal operation, a permissible tolerance of the line voltage of +10% and a possible derating of the arrester of –20% were taken into account. Your MOV value is VC1/2. and can connect line side (Load side got a fuzzy voltage level (on-start/on-stop)).
How does surge suppression work with gas discharge tube?
Another common surge suppression component that can survive very high surge currents is the gas discharge tube (GDT). GDTs achieve their impressive current handling ability by having an abrupt trigger voltage at which they switch into a conducting state that is almost a short circuit. This is sometimes referred to as a “crowbar” characteristic.