Electromechanical relays

Electromechanical relays

RELOG switch relays

RELOG stands for a system of state-of-the-art electromechnical switch relays that meets the requirements of modern industrial control systems to a large extent in terms of its electric and structural parameters. The RELOG relay is used in industrial plants that require a reliable relay designed for long-term use. The wide variety of available models makes it possible to adapt to the majority of applications. This includes the available control voltage as well as contact designs and signalling options. The switching relays for the RELOG system are supplied in housings with a plug connection.


  • Complete with plug-in socket, adapter for top hat rail mounting or adapter for screw mounting
  • Slotted or solid plastic cap, metal cap
  • 4 or 8 changeover contacts with single or twin contacts
  • Special models for rail vehicles with extended voltage range (UIC model)
  • Degree of protection: IP 40


  • Drop indicator or flag indicator
  • Gold-plated contacts for switching the smallest loads
  • Silver-palladium contacts for switching in adverse environmental conditions (such as sulphurous atmospheres)
  • Retrofittable special cover for all 2RH models with closed cap to increase the degree of protection to IP 50

Type overview

  • 12 V to 220 V DC
  • 12 V to 400 V AC

Special models

  • RELOG 2RH01s with forcibly guided contacts
  • RELOG 2RH01i with increased ampacity (up to 10 A)
  • RELOG 2RH01f with reduced response time <15 ms
  • RELOG 4RH50 with dual coil

Switching relay

The relays in the RH series (RH04, RH32, RH33, RH34) can be used in plant engineering and control technology as switching relays based on a direct or alternating current. Thanks to the design type (closed housing construction), the RH32 is intended for use in challenging industrial applications (contaminant level 3). This design is to prevent the ambient air from reaching the cadmium-free contacts.

RH 04 (24 V to 220 V DC)
RH 33 (24 V DC/AC to 220/230 V DC/AC)
RH 34 (24 V to 230 V AC)

  • 17.5 mm installation housing
  • Currents up to 16 A, also suitable for lamp loads
  • Integrated free-wheeling diode
  • Manual operation
  • Suitable for snapping onto 35 mm top hat rails

RH 4      - Switching relay operated by a direct current
RH 33    - Switching relay operated by alternating and direct current

The RH 33 is suitable for switching from smaller to bigger loads with appropriate prior knowledge of preloading.

RH 32 (12 V to 230 V DC/AC [250 V DC])

  • 22.5 mm top hat rail housing
  • Control with direct or alternating current, which also permits 16 2/3 Hz
  • Two powerful changeovers with currents up to 8 A
  • Direct current with up to 300 V
  • Housing: flame retardant, self-extinguishing polycarbonate according to UL94 VO
  • Temperature range from 40°C to 70°C
  • Five models for rated current range from 12 V to 230 V AC and 250 V DC
  • Varistors and free-wheeling diodes protect the relay on the input side and the connected devices on the input side protect the relay and connected devices

Signal relay

The RA70 is used for signalling and monitoring operating conditions, interruptions and faults in energy creation, distribution and almost all other industrial plants.
Examples include:

  • Operating conditions in plants or plant sections
  • Exceeding limits, for example temperatures or pressure
  • Faults caused by triggering protection devices for transformers, motors, and generators in generation and distribution plants
  • Voltage failures when monitoring control current circuits

The signal information (including faults, interruptions, and power outages) is saved until it has been acknowledged (manual operation of drop indicator) and the cause of the signal is rectified. The contacts activated by the signal relay for signal information can be used for visual and/or acoustic alarms or to control additional relays – for example, to switch off faulty devices. If required, a wiping contact can facilitate the control of an acknowledged switching current for the central signalling of faults or other signal information.

Contact variants

  • 2 changeover contacts
  • 1 changeover / 1 wiping contact
  • 1 changeover / 1 direct changeover
  • 1 changeover / 1 normally-open contact in middle position
  • 1 wiping contact / 1 normally-open contact in middle position


  • Closed current
  • Operating current


  • Without acknowledgement

Suppressor circuit

  • Diode suppressor circuit
    (only approx. 0.7 V DC)
  • Varistor suppressor circuit
  • RC protective circuit

Special design

  • RA70 with dual coil