Premium Membership ♕

Save 50% on all Video Courses with Enterprise Membership Plan and study specialized LV/MV/HV technical articles and guides.

Relay cycles

Due to the self induction of the coil and the inertia of the parts to be moved, on activating a relay the operations do not take place suddenly. The function diagram below shows the different cycles for the most important relay configurations of undelayed power relays.

Unless otherwise stated the indicated times are maximum values, the cycles specified apply to DC-coils energized with rated voltage (without any components in series or parallel to the coil) and at the reference temperature.

  • operate time
  • release time/reset time
  • bounce time
  • minimum energization duration

Relay Technology Categories

The ‘Relay Technology Categories’ describe the degree of sealing of the relay case or its contact unit. See ‘Category of environmental protection’.

Relays with forcibly guided contacts

The compliance with regulations for the safety of persons and material is imperative in our technical world. National and international regulations take various risks into account. These safety standards also make demands on components which share with their function the safety level of a plant, machine or the equipment. For safety relays the demand for forcibly guided contact system according ZH1/457, issued by the professional association applies; the contacts have to be linked mechanically in a way, that NO and NC contacts may not be closed at the same time.

It has to be ensured that over the entire life and even in case of malfunction (e.g. contact welding) the open contact gap will be at least 0.5 mm. If specified they also comply with the wider requirements according to EN 50205 “relays with forcibly guided contacts”


Process in which a monostable relay shifts from the operate state
back to the rest state.

Title:Relay definitions
Download:Right here | Video Courses | Membership | Download Updates

Premium Membership

Get access to premium HV/MV/LV technical articles, advanced electrical engineering guides, papers, and much more! It will help you to shape up your technical skills in your everyday life as an electrical engineer.
50% Discount 💥 - Save 50% on all 90+ video courses with Enterprise Membership plan.

More Information

One Comment

  1. djelaili noureddine
    Jun 26, 2020

    i need courses in electronic and controle

Leave a Comment

Tell us what you're thinking. We care about your opinion! Please keep in mind that comments are moderated and rel="nofollow" is in use. So, please do not use a spammy keyword or a domain as your name, or it will be deleted. Let's have a professional and meaningful conversation instead. Thanks for dropping by!

  ×  two  =  six

Learn How to Design Power Systems

Learn to design LV/MV/HV power systems through professional video courses. Lifetime access. Enjoy learning!

Subscribe to Weekly Newsletter

Subscribe to our Weekly Digest newsletter and receive free updates on new technical articles, video courses and guides (PDF).
EEP Academy Courses - A hand crafted cutting-edge electrical engineering knowledge