FIELD: rail transport; electrical equipment. SUBSTANCE: in case of skidding (slipping) of one or several wheelsets and change of voltage across maximum signal separation unit, traction motor currents are reduced due to automatic correction of preset value of current at input of rolling stock automatic control system regulator. Excessive slipping of all wheelsets of electric rolling stock cause change of signal at output of minimum signal separation unit (maximum signal separation unit) proportional to acceleration (deceleration) of wheelsets with minimum (maximum) speed, as a result preset current value is decreased and synchronous skidding of wheelsets is eliminated. Skidding of wheelsets in truck (section) cause change of signal at output of maximum signal separation unit (minimum signal separation unit) which leads to pulsed delivery of sand under skidding (slipping) wheelsets. Increase (decrease) in rotational speed of wheelsets provides reduction of currents of traction motors coupled with skidding wheelsets. Sanders are operated by signal from comparator. Two channels are provided for sanding to increase sensitivity and speed of response of protection in any zone of traction motor characteristic curves. False operation of sanders in service is prevented. EFFECT: enhanced operation reliability. 3 cl, 1 dwg
