Self-starting control unit Щ23М (unit Щ23М) is meant for operation in control circuits for low-voltage asynchronous motors and for effecting the self-starting of asynchronous motors (automatic repair of electric motors operation) after short-term (not exceeding 5 sec.) power interruption or after relay protection devices’ functioning.

  • Unit Щ23М is an electrical product of the general industrial purpose.
  • The application field of unit Щ23М covers enterprises of petro chemical and oil processing industry.
  • Unit Щ23М provides activation of starting control devices of asynchronous motors with control coils on nominal voltage of 220 or 380 V. Self-starting of electric motors is activated through circuit closing, blocking the START key of the starting control device.
  • Unit Щ23М provides the issue of instruction to self-starting with a time delay, defined by external circuits, in the range from  0 up to 10 s.
  • Connection of several units Щ23М allows providing the in-turn-group mode of self-staring of a group of electric motors.
  • Unit Щ23М is stable to the effect of nominal values of climatic factors for УХЛ performance of arrangement category 3.1 according to GOST 15150-69.
  • The level of protection of unit Щ23М from touching the live parts and from ingress of hard foreign bodies and water, provided by enclosures – is IР20 according to GOST 14254-96.
  • Unit Щ23М is fireproof by operation and under  emergency situations.
  • эксплуатации и аварийных ситуациях.


  Electric power supply of unit Щ23М – one-phase alternating current with the following parameters:

– voltage – 220 V with the permissible deviation from minus 15 up to plus 10 %;

– frequency – 50 Hz with the permissible deviation ± 2 %.

  Working position of unit Щ23М by operation:

vertical, permissible deviation from the working position shouldn’t exceed 5° to any side.

  Contact number of the output body (number of electric motors started) ‑ 1.




   Structurally unit Щ23М is made as a single device.

   All elements and constituent parts of unit Щ23М are structurally installed on a plastic base and are covered with a plastic casing.

   The following elements are backed out to the upper cover of the casing:

– tumbler switch of switching operation modes ON-OFF-CONTROL;

– signal lamp CIRCUIT;

– control lamp CONTROL.

      On the side of unit Щ23М there is a terminal block, closed with a cover, which provides the external connection of the unit (including the setup of the time delay of issuing the instruction to self-starting).

Connection scheme of unit Щ23М to the control device of the electric motor by individual self-starting   Connection scheme of unit Щ23М by in-turn-group self-starting with blocking the starting sequence

Technical data

  • Overall dimensions of unit Щ23М do not exceed 220 ´ 140 ´ 150 mm.
  • The weight of unit Щ23М is not more than 2,5 kg.
  • Nominal switched voltage of contacts is up to 380 V.
  • Nominal current of output contacts is 6 A.
  • The total power, consumed by block Щ23М in waiting mode doesn’t exceed 4 V·A.
  • Unit Щ23М provides the issue of instruction to self-starting of an electric motor after power interruptions not exceeding 5 s.
  • Unit Щ23М provides the issue of instruction to self-starting by the minimal value of the recovered line voltage, lying in the range from 190 up to 200 V.
  • Unit Щ23М provides the issue of instruction to self-starting with the time delay, defined by external circuits, equal to 0, 2, 4, 6, 8 & 10 s.
  • Relative error of instruction issue to self-starting with the time delay equal to 2, 4, 6, 8 & 10 s – doesn’t exceed ± 10 %. The error of instruction issue delay to self-starting by the value, set by the external circuits, equal to 0 s – doesn’t exceed 0,5 s.
  • Unit Щ23М doesn’t issue the instruction to self-starting of an electric motor, switched off by the external circuits.
  • Unit Щ23М provides the control of readiness to self-starting actuation in the waiting mode of power interruption.


Example of record by ordering self-starting control unit Щ23М  –

                   Self-starting control unit Щ23М  НМЕК.403455.001 ТУ.