1. HAN, Chang-Kyu, YANG, Seon-Woong, LEE, Kyung-Ho, JUNG,
Hun, “A study on thermal behaviour prediction for automotive
electric relay based on CFD”, 24th International Workshop on
Thermal Investigation of ICs and Systems,2018
• Electronization for car such as HEV and EV tend to control and
manage high current demands the automotive relay
• Accurate thermal analysis based on CFD was made in order to
optimize the inner structure of relay
• CFD model are analyzed with changing the contact size’s, busbar
thickness and connection method (series or parallel)
• No temperature effect on diameter change of electric contact
• change in electric busbar thickness effectively decrease busbar
and relay assembly’s temperature distribution
• parallel connection method is effective (reduced busbar & relay
temperature distribution).
• But, there is a chance of over heating for busbar parallel
connection
2. Y Zheng, X Fan, Weijie Zhang, Xin Zhang,“Steady-state thermal
analysis simulation of magnetic holding relay contact based on
Finite element analysis”, 12th International Symposium on
Computational Intelligence and Design (ISCID),2019
• Thermal analysis of relay based of FEA was performed using
ANSYS software.
• Three heat dissipation methods of conduction, convection and
radiation in the heat transfer process are considered
• Moving contact surface is the main heat source of causing the arc
spark.
• As the input current level increases, the accumulation of heat
between the contact surfaces, between the contacts will cause the
temperature to rise
• The movement of free electrons between the contact metal contact
faces increases the number of corresponding carriers, thus causing
the contact resistance to decrease
3. Min Tian, Feng Ding, “ Thermal-electrical Coupled Simulation
Analysis of Sealed Electromagnetic Relays”, Atlantis Highlights in
Engineering, Inter Conference on Precision Machining, Non-
Traditional Machining & Intelligent Manufacturing (PNTIM
2019)
• The effects of ambient temperature and voltage intensity on the steady state and
transient temperature field of the relay were analyzed
• Ambient Temperature on Steady-State
– The temperature of the relay rises as the ambient temperature increases. The
highest temperature point is at the coil. The temperature distribution of relay is
uniform.
• Current Intensity on Steady-State
– The position of the highest temperature point changes with the change of
current
– The heat generated by the contact resistance is the main heat source when the
load current is greater. Hence, the contact resistance should be strictly
controlled for large load current to ensure the reliability of the relay.
• Analysis of Transient-state Temperature Field
– The maximum temperature point of the relay will shift (coil element to contact
element) with the increase of the current grade and the distribution of
temperature is not uniform.
4. Xu Zhang, Wanbin Ren,“Experimental Investigation of
Contact Welding Characteristics of Electromechanical
Relays”, IEEE Transactions on Industrial Electronics,2020
• The contact dynamic welding characteristics of relays are investigated
in the MO, BO and M&B with the resistive load.
• Contact force, contact voltage and contctcurrent are described along
with the analysis of welding force and bounce energy, contact
resistance, molten bridge energy and break arc energy.
• Changes in bounce energy determine the welding force, which is
inversely proportion to the contact resistance.
• The welding force is affected by the variation in molten bridge energy,
which is inversely proportion to the initial contact area.
• It results that the strongest welding occurs in M&B operation mode,
while the weakest welding occurs in BO operation mode.
• The consecutive bounce arc and break arc largely varies the contact
area and welding area, also it is the root cause of contact welding force.
5. Seulki Hwang,Daesup Hwang,Hani Baek,Chansun Shin,
” Effect of Copper Based Spring Alloy Selection on Arc
‑
Erosion of Electrical Contacts in a Miniature Electrical
Switch”, Metals and Materials International - 2019
• The effects of spring beam materials on the contact erosion was
analyzed in spring beams made of BeCu,(TiCu) and CuNiSi alloy
• The spring beam are tested over 30,000 operations under the
voltage of 12 VDC and 9 A
• BeCu and TiCu - material transfer from anode to cathode
• CuNiSi - material transfer from cathode to anode
• TiCu and BeCu alloys have good stress relaxation performance,
whereas Cu-Ni alloys exhibit inferior stress relaxation
performance
• Stress relaxation represents the loss of stress, hence, the spring
beam loses its ability to hold contact force, and small vibration
occurs at the beginning of releasing the external switch button
6. Fabian Schipperges, Felix Jialei Luo, Jozsef Gabor,
Dr.Ing. Bernard Bäker,“Reliability Assessment of a
Redundant 12V On-board Power Supply Using Solid-
state Safety Relays”, Automotive meets Electronics-2019
