What do you mean by legs on the pillars of the shaker?

L line, e grounding, g shielding.

There are three pins on the shaking table terminal, namely: L to the conductor part of the tested equipment or line, E to the shell or ground of the tested equipment or line, and G to the shielding ring of the tested object or the part that does not need to be measured.

The shaking table is a measuring instrument commonly used by electricians. It is mainly used to check the insulation resistance of electrical equipment, household appliances or electrical lines to the ground and between phases, so as to ensure that these equipment, appliances and lines work in a normal state and avoid accidents such as electric shock casualties and equipment damage.