How can you tell if a capacitor is a MOV?
How can you tell if a capacitor is a MOV?
A MOV part number usually doesn’t ‘look’ like it corresponds to a capacitance value. They will have some safety marks on them as well. It will often have a ‘smooth’ case like a Y-capacitor. An NTC can best be checked by measuring for resistance – a good Y-cap and a good MOV will appear open-circuit to a multimeter.
How do you select a metal oxide varistor?
The first step of choosing a MOV is determining the continuous working voltage that will be provided across the varistor, you have to choose the varistor with maximum AC or DC voltage that matches or slightly higher than the applied voltage.
How is varistor connected?
Varistors are connected in circuits across a mains supply either phase-to-neutral, phase-to-phase for AC operation, or positive-to-negative for DC operation and have a voltage rating to suit their application.
Is varistor same as a capacitor?
You may confuse them with capacitors. However Varistors and capacitors have nothing more in common than their size and design. A Varistor is used to suppress voltage, whereas a capacitor cannot perform such functions.
How do I select varistor value?
Therefore, in general, when we select a varistor, the flow capacity should be calculated by pressing the 10 to 100 impacts in the rating curve of the varistor surge lifetime. The actual surge current passed is about 30% of the maximum impact current. (Ie 0.3I).
How do I select a MOV value?
MOV Selection Guide | Power Supply Peripheral Design Series
- (1) Wide working voltage range (mainstream 18-1800V, divided into several grades).
- (3) Strong impulse current resistance (up to 100-15000A).
- (1) Step 1: VARISTOR VOLTAGE calculation.
- (2) Step 2: Calculation of MAXIMUM ALLOWABLE VOLTAGE.
What do the numbers on a varistor mean?
I = current through the device. k = a constant for the component. V = applied voltage. n = value for the device style. Typically for silicon carbide the value of n is between about 3 – 7, but for zinc oxide device the value can be in the region of 20 – 50 making the characteristic much sharper.