Coronet Herald Power Lead

[Bunsen]

I have a Coronet Herald Lathe and have a question about the power supply. The lathe was supplied with a normal "kettle" lead that will plug the lathe directly into the wall socket. There is also a heavy black plastic box with the connections that allow the box to be fitted between the mains lead and the lathe. I unscrewed the top of the box and it is full of wires and some sort of electrical components wrapped in silver foil. I quickly put the lid back on!.
I can't find any information from Record Power about this box.
Does anyone know what it is for and does it have to be fitted :?:

Thanks

 

[Bunsen]

Problem solved.
Apparently the black box is an EMC filter. Record Power recommend that it is fitted but do say that its existence is not mentioned anywhere in the lathe manuals .

 

[ajcr27]

I have a Coronet Herald Lathe and always wondered what the black box was, so thanks for sharing update.