In article mathematical modelling of process of formation and deduction of polluting particles layer of dielectric liquids on electrodes is considered at electroclearing. As a result of modelling,the electric forces keeping particles at an electrode and gravitational forces were compared, the parity of the sizes of particles and pressure on electrodes at which gravitational forces can be considered is shown. The estimation of influence of Brown (thermal) movement for a thickness of a layer of particles kept at an electrode is spent at electroclearing.