There is a task to choose a varistor to protect the AC circuit, controlling several coils of magnetic starters.
- Mains voltage 230-240V AC
- Frequency: 50Hz
- Starting current of coils of magnetic starters: 3A max
For these purposes, I want to use the LA series varistors from LittleFuse.
- Vm (AC): 275V
- Vm (DC): 369V
- Varistor voltage: 387V (min) - 473V (max)
- Clamping voltage: 710V
- Vm (AC) - Is this a normal mains voltage?
- Do I need to find the peak voltage amplitude to select Vm (AC)?
Mains voltage: 230V
I must multiply this value by √2 and add 10% margin. 230 * 1.41 = 324.3V + 10% = 347.3V