Solid state relay blows the fuses in my speakers

[Circlotron]

Interesting that with a perfect inductor with no resistance and no core losses, when switched on at the zero crossing the current will always remain one side of zero. It will continually rise to a peak value and fall to zero but never reverse even though the AC supply does.
-----
It suddenly occurred to me, provided you could find a perfect inductor you could make a DC power supply from an AC source without needing a rectifier diode! LOL

Eidt -> seems that would only work if you needed a supply that would supply current only, at zero volts output...

[Zero999]

I've just realised, I wasn't very clear when I said ideal inductor, I was talking about the core, not in terms of zero winding resistance. Anyway, I think it's settled that turning on an inductive load, at the point of zero crossing is worse, than at the peak voltage.

[David_AVD]

Interesting stuff about the zero cross and the transformer current.

It would seem easy enough to always turn on at the peak of the cycle (90° from zero cross) with a micro and zero cross detection.

When would be the idea time to turn the transformer back off again? Does the relative phase compared to the turn on cycle matter?

[Circlotron]

When would be the idea time to turn the transformer back off again?

If the SSR has a triac or two SCRs it will turn off at (close to) zero current. That means there will be almost no energy left in the transformer primary inductance to cause a voltage spike. A sudden rise in voltage across the SSR but no inductive spike. 

[David_AVD]

So ultimately it doesn't matter which half of the cycle you turn on (at 90°) or off (at 0° / 180°) ?

[Gyro]

Correct. As long as you avoid repeatedly turning it on at a zero crossing, nothing else matters.

[f4eru]

this still points to faulty design principles in the transformer/fuse
If the fuse is not chosen to withstand some phases of switch on, then it will also fail randomly in normal manual switching....
Very bad.
Either the fuse should be selected differently, or an inrush device limiting added, etc....

[Gyro]

True, it is marginal, but switching on a zero crossing every time is a good way of accelerated ageing a fuse.