Blender Smells Burning When Used Whenever I Use My Blender, It Smells Like Burnt Copper/metal/or Battery?

Whenever I use my blender, it smells like burnt copper/metal/or battery? - blender smells burning when used

I bought a blender from my old neighbor. Whenever I used to grind vegetables / fruit or ice, a battery strong odor like copper or odor that made by the mixer. I use the blender several times and each time I use it, the smell is still there. This is the cause of the odor has a negative impact on health? I want to be healthy, drink vegetable juice, but I'm paranoid, that smell! Please enlighten me.