Capacitor

https://electrical-engineering-portal.com/few-things-that-capacitors-do-perfectly

https://www.qualtecheng.com/docs/harmonics/QT-614.pdf

What you have to do is ask yourself, why is this capacitor here, what is its function? ...and have things changed regarding this reason...like a change in load characteristics?...or a capacitor bank added? ...or some other modification...Has the new capacitor been recommended by an engineer or industry professional?...surely this isn't some random part you just had lying around, it was ordered for a reason, or did you receive the wrong part? What will happen depends on these facts...

More information will yield more and better results.

A circuit diagram,perhaps,frequency,application?

All these acronyms have got to stop!---- ASAP!

Looking at the capacitor supplied you would need 2 in parallel to provide 150nF. Another parameter is the tolerance % of the capacitor. Ie +-5%, +-10% +-20%.

You could measure the capacitance of the replacement capacitor to see its actual capacitance and then determine a parallel replacement to give 120nF.

thank you very much for your reply

How did the telephone call between the original equipment manufacturer and the <...we...> go?

What you don't know CAN hurt you in some cases.

It certainly has the capacity to do so...

Very good,2 dogs.

Is '2 dogs' his spirit name?

No,it is the name of a spirit:Two Dogs Lemon Brew,a lemon based alcoholic beverage originating in Australia.A very sharp drink,like the answer.

In cases of deciding whether a replacement part will work, you need to consider what the original part was used for.

In electronic circuits, if the capacitor is used for timing, you absolutely need to used the exact same spec. If you use a different spec, you need to have something to adjust the timing or you'll need to change some other parts to get the exact, same timing.

If it's used for power rail filtering, you might get away with a slight difference in spec if the circuit is a low frequency circuit (say for audio). In high frequency applications, it might have an effect, particularly with noise or interference.

Having said all that, I would have to say that the difference in capacitance of your replacement part is too large no matter what the application is.

In short, no, I don't think you can use it.

regards,

Vulcan

Ah: Generator circuit breaker?

Do you have a circuit diagram; or can you take a picture so that we can reverse engineer the circuit.

What sort of circuit is it in?

<...can we use it...>

CR4 is not a permission-giving entity.

He didn't say "May we use it?" he said "Can we use it?": which opens up a totally different kettle of red herrings .

Ah! That explains things, because the two verbs are interchanged without due care in modern parlance.

<... kettle of red herrings...> Burpy pardloes.

No ...Effect will be expected consequences,but not good.

Assuming your GCB you mean Generator circuit braker, the capacitor is there to absorb some of the system inductance stored energy in order to avoid contact arcing damage. Well, those components are chosen with high safety margins and since it failed some underlying problems can be hiding like bad contacts, chattering etc. I'd start from there, and choose a same or higher voltage rated cap if possible. Choises change whether we are talking for DC or AC gen. S.M.

The surge arrestor acts like a dead short when the voltage exceeds a certain threshold.

The capacitor acts like a resistor to limit the amount of current through the surge arrestor.The resistance increases as the frequency of the surge increases,so a very fast surge(which is normal) will pass less current through the surge arrestor.It is a sacrificial device intended to fail to prevent a catastrophic failure of the surge arrestor.If the capacitor failed,the surge arrestor probably also failed.

It should be replaced with the same type and rating to preserve the design integrity of the surge arrestor circuit.

Chances are pretty high that the surge arrestor is also damaged.

I suggest replacing both to prevent compromising protection of downstream components.