What is a variable speed drive? A variable speed drive is a piece of equipment that regulates the speed and rotational force, or torque output, of an electric motor. The background and technology. There are millions of motors in use in industry and offices around the world.
The specific gravity for Obsidian is 2.35, it's refractive index is 1.48-1.51, and it's double refraction is None. History Obsidian is named after a Roman, Obsius.
What is the unit measure of specific gravity? specific gravity = relative density ( relative to water), water is 1000 kg / cubic metre, say iron is 7800 kg / cubic metre, then relative density is: 7800/1000 = 7.8, or 7.8 â¦ times the density of water