Singer Sewing Machine Motor?

Hi,
i recently found an old electric singer sewing machine and have been tinkering with it. The motor/light that came with it worked, but i seem to have made it explode.

On the top of the motor it says ac/dc 220/250v, its got 4 connections for a plug (which i dont have). One of the connections is definitely earth, and i THOUGHT that one other was neutral, then 2 live connections for the motor and light.

I just plugged in what i thought was motor live and common neutral today and a small black box wired in parallel with the motor exploded. I realised later that i had plugged neutral into live and vice versa.

The box (what is left of it) says **ilier **pressor (suppressor?) 0.02uf +/- 20% 250vacwkg sc/k. What is it? Why was it there? and why did it explode?

I should say that before this i plugged in live for the light and common neutral and the light worked fine, i also had the motor going briefly but it stopped because i think i got oil in the brushes.

Thanks!