How do I read varistor code?
How do I read varistor code?
Touch one meter probe to the free varistor lead and the other probe to the connected lead. Read the resistance on the meter. If it reads nearly infinite resistance, the varistor is still good. If it reads very low resistance, the varistor is blown.
How do I choose a .MOV size?
First Step: Determine the application’s surge requirement. Typically, the MOV data sheet will state the Imax (Maximum Current). For example, a 10 mm MOV disc is rated about 3 kA based on the 8/20 µs, a 14 mm MOV disc is rated about 6 kA and a 20 mm MOV disc is rated about 10 kA.
What is a varistor and how does it work?
When a voltage surge exceeding a specified voltage (varistor voltage) is applied, the varistor suppresses the voltage to protect the circuit. When the voltage surge does not exceed the varistor voltage, the varistor works as a capacitor. If the peak pulse current rating is insufficient,then the varistor may be damaged.
What are varistors made of?
Varistors are voltage dependent, nonlinear devices which have electrical characteristics similar to back-to- back Zener diodes. They are composed primarily of ZNO with small additions of other metal oxides such as Bismuth, Cobalt, Magnese and others.
How do you identify a varistor?
While it may look similar to a capacitor, you can identify the device by its color, markings and location. The MOV will always be close to the equipment’s power supply and wired to a fuse. Many MOVs have a bright, solid color and are usually coin-sized. Unplug the equipment from the electrical outlet.
How do you calculate a varistor?
The simplest ways of determining the current duration are simulation or measurement (τ = t*r). The time constant can also be calculated to an approximation with equation 13. Here the varistor resistance of voltage class K20 is calculated for 1 A.
How do I know if my varistor is bad?
How do you test for a bad varistor?
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 test a MOV varistor?
Touch the meter probe tips to the MOV’s leads and measure its resistance. If it has a resistance much under 100 ohms, it has blown. Desolder and remove the remaining lead and remove the MOV from the equipment. If the part has resistance over one million ohms, it is still good.
Is there a way to identify a varistor?
The problem I am having is the markings, other than the voltage don’t seem to corrolate with anything. So I’m not sure if it is a varistor or if it just has obscure markings. The markings are : 05 K385 1146 I know the k385 is the voltage from what I can find, but have no idea what the current is or what part number it matches up with.
How to tell if a varistor is an electric fence?
So I’m not sure if it is a varistor or if it just has obscure markings. The markings are : 05 K385 1146 I know the k385 is the voltage from what I can find, but have no idea what the current is or what part number it matches up with. It’s currently part of the 12v input on an electric fence energiser.
What is the maximum RMS voltage of a varistor?
not present PARAMETER VALUE Maximum RMS voltage 60 V Maximum DC working voltage 2 x 60 V = 85 V Varistor voltage 100 V ± 10 %