How to Convert Transorbs Transient Energy from Watts to Joules.

[Venkatlab]

Hi All,

I'm trying to replace MOV(130VAC,21Joule) used in circuit with transorb(rated for 170V,1500W).
So i want to convert Watts to joule & compare the energy of Transorb with MOV

Appreciate your Help.

Regards,
Venkatlab

 

[WimRFP]

Hello,

You may know that E [J, Ws] = P [W] * t .

If P versus time curve is rectangular, you can use the formula directly. So 1500W during 1.7us results in 2.55 mJ

when not rectangular, you need to integrate the P versus time curve the find the surface area under the P versus time curve.

the datasheet of the transorb mostly gives a graph that shows peak power dissipation versus pulse duration. If the pulse is an exponentially decaying pulse, you can just use:
E = (Peak power)*(to 36% decay time).

Besided the power and energy rating, you should also evaluate the nature of the pulse (impedance, peak current), as this may result in different actual clamping voltage for the transorb w.r.t. the MOV.