INTERNATIONAL SESSION ON ELECTRO-MECHANICAL DEVICES 2003 (IS-EMD 2003)
(Record and Abstract)
November 20-21, 2003
Shinkobe Oriental Hotel,
Sponsorship: Technical
group of Electro-Mechanical Devices in the Electronics Society of the
Co-sponsored: The Research
and Engineering Meeting of Electromechanical Components and Contact Technology,
with cooperation from IEEE CPMT
Technical
program
Thursday, November 20, 2003
[Session 1]
--Contact phenomena (1)—
Chairs: J.W.McBride (
1.EMD2003-60
Surge
current strength of electric power contacts
Achim Brenner, Horst F. Nowacki (HARTING KGaA)
Heavy Duty connectors for electrical equipment must be designed for the worst electrical and mechanical conditions. Generally electrical power contacts should absorb high current surges up to 100 times of nominal rated current for milliseconds without sustaining any damage.
In this presentation the authors consider in detail the problems relating to parameters like contact normal force, the effective contact areas and the surface plating, which have significant influence onto the surge current strength of electrical power contacts.
Obtaining the behaviour of machine turned pin and socket contacts with different pin diameters the parameters of the active contact area radius, the constriction resistance and the constriction temperature are calculated by using FEM for elastic / plastic surface deformation. With the knowledge of the constriction radius the temperature curve of the contact area was determined by coupled electrical / thermal FE calculation.
Laboratory tests were carried out in order to verify the FE- calculation.
2. EMD2003-61
The effect of environmental contamination on gold plated contacts in
portable lectronic devices
Zhou
Yilin, He Zhanping, Zhang Jigao (Beijing Univ. Post & Telecommunications)
Serious environmental contamination influenced the reliability of gold
plated connectors in some portable electronic devices. Gold plated contacts disassembled
from failed devices were tarnished and worn, contact resistance increased over
design limitation. The element compositions of contaminants on gold plated
contacts were complex, including C, O, Si, Al, S, Cl, K, Ca, Na, Mg and so on,
which might be inorganic and organic compounds. Small part of them come from
manufacturing and assembling process, others were mainly formed and deposited
during customers’ using periods.
3. EMD2003-62
Observation of bridge size in micro-gap by using cantilever used gap
control system
Yoshitomo Watanabe, Hiroyuki Ishida, Masanari Taniguchi, Tasuku
Takagi (Tohoku
According to our former experiments, the cyclic
convex waveforms of the bridge-voltage were observed at the instant of the
contacts separation with a micro-steps of 0.5μm each and holding the constant contact gap with
step by step. In order to investigates this phenomenon more precisely, the
authors have developed a new micro-gap separating system using the cantilever.
The observed results are shown in this paper for Pd contacts. A cylindrical
bridge was observed. An interesting phenomenon was observed that the contact
gap shrank as the current increases and it expanded as the current decreases.
This gap variations can be assumed due to temperature variation of the contact
bridge. In this paper, the images of the bridges and the measured data of the
bridge length and the diameter of the cylindrical bridge are shown.
4.
EMD2003-63
A consideration for oscillating increase of contact
resistance between gold and copper in the process of oxidizing
Isao Minowa, Takahito Tanaka, Masahiko Gotoh (
Contact resistances between gold wire
and copper block white surface was oxidized from clean state to 200nm
thickness were measured Those contact resistances showed oscillating increase
and finally reached to very high value at 200nm.
In
this paper ,a consideration that diffusing process of oxygen molecules toward
inside the copper block is not simple, but bonding between copper and oxygen
cause insulating layers and semi-conducting layers, is presented.
5. EMD2003-64
Impact of lead free soldering processes on the reliability of
electromechanical switching devices
Werner
Johler (Tyco Electronics AXICOM)
Various effective and draft legislations and
rules in Europe (WEEE – Waste
Electrical and Electronic Equipment ROHS – Restrictions on the use of certain
substances and ELV – End of life of vehicles) and Japan (Recycling Law for Home
Electric Appliances) have either targeted restrictions or a full ban on the use
of lead, to be enforced from 2001, 2003 and 2006 onwards.
Up to now, mainly tin-lead alloys have been used in
electronics. The process temperatures usually applied have been in the range of
230°C. All currently discussed lead-free alternatives for professional
electronics need process temperatures which are at least 20° higher. In
addition, the process duration is significantly longer. The combination of
higher process temperatures and longer duration, results in a significant
thermal stress on electromechanical devices. Especially the precision mechanics
of electromechanical relays must withstand the solder process with maximum
process temperatures of 255° C without dimensional changes.
During the transition from tin-lead to
lead-free soldering processes all
combinations of component surfaces and solder must be possible. The selection
of pure Sn100 or SnCu0.7 as terminal surface allows mixed assemblies with
tin-lead as well as lead-free solders. All tested combinations of terminal
surface, PCB surface and solder showed good results. From these results it can
be concluded that mixed assemblies are possible during the transition time
without any negative impact on the reliability of the electronic devices.
[Session 2]
--Measurements and evaluation--
Chairs:
Ben Jemaa (Univesity of
6. EMD2003-65
The 3D measurement and analysis of high precision surfaces
John W. McBride (
The paper reviews methods for the measurement and analysis of high precision surfaces. A number of measurement techniques are discussed with the emphasis on the application of con-focal methods. The various techniques are compared in terms of measurement times, data density, and the ability to detect near vertical surfaces, and steps. The two sensing methods discussed are the auto-focus laser method and the white light methods. Particular applications considered are in the measurement of eroded electrical contact surfaces, spherical and near spherical surface, and MEMS. The particular emphasis here is on the metrology of such surfaces and devices and methods for the assessment of complex micro-machined surfaces. The paper points to a number of directions for improved metrology and discusses these in the context of the application given.
7. EMD2003-66
Theoretical investigation on the current measurement with sensor
arrays taking into account the interface
Yao Jianjun, Wang Jing, Wang Jianhua, Geng Yingsan (Xi'an Jiaotong University)
A single solid-state magnetic sensor can be used to measure a current by sensing the field near the conductor in a non-contact way. In order to improve the accuracy of the measuring system, magnetic sensor arrays have been introduced in the current measurement around the conductor. An analytical algorithm based on Discrete Fourier Transform (DFT) is presented in this paper, which can separate the effects of the field generated by the current under measurement from the interference fields. A general mathematical model of the interference analysis is set up, which can be used for both DC and AC current measurement and has no restriction on the shape and number of the current conductors. Numerical simulations associated with preliminary experimental results confirm the validity of the approach.
8. EMD2003-67
On-line temperature measurements with sensor technology on
switchgear
Rong Mingzhe, Wang Xiaohua, Jia Shenli (Xi'an Jiaotong University)
Based on the principle of infrared radiation, a non-contacted sensor that can be used on-line to monitor the temperature in switchgear is developed. Some factors such as temperature detection range, ambient thermal source, object’s surface condition and thermopile detector’s temperature, which will affect the reliability and precision of the sensor are studied. Some measurements that can improve the sensor’s performance are given. The measurements include deciding suitable temperature detection range, eliminating the disturbance of the ambient thermal source by a special shell, eliminating the effect of the varied surface hence different radiation rate by painting special dope, especially eliminating the influence of thermopile detector’s temperature which varies following the ambient temperature by using compensation technique through software.
9. EMD2003-68
Identifying the frequency response of common-mode current on a
semi-rigid cable attached to a PCB
Yoshiki Kayano, Motoshi Tanaka, Hiroshi Inoue (
Frequency response of common-mode (CM) current on a feed cable attached to a printed circuit board (PCB) is studied experimentally and with finite-difference time-domain (FDTD) modeling. Several different configurations are prepared to demonstrate effect of PCB dimension on resonance frequencies of CM current. From the results, EMI antenna in the frequency band around the first resonance was comprised of the ground plane and cable. However, the second resonance resulted from a trace of the ground plane. Resonance frequencies of CM current are independent of termination condition. This study can be a basic consideration to realize a technique which is effective on the suppression of the CM current on the PCB with a connected feed cable.
10. EMD2003-69
A study on transmission characteristics and EM field distributions
on the transmission lines with difference of structure
Ken-ichi
Takahashi, Takashi Kasuga, Hiroshi Inoue (
In the next generation, hard disk drive (HDD) with the large storage
capacity and the high density will require speed-up of the signal transmission
and miniaturization of the size for the transmission lines. Hence, as the
signal transmission line (STL) led from the magnetic head in HDD at high
frequency should be investigated not only for signal integrity but for EMC. So,
various structure of STL in the head part, which has appropriate characteristics,
should be proposed. In this paper, the enlarged models, which have different
structures on cross-section, are simulated as the transmission line in the
magnetic head. To estimate the effect on transmission characteristics and
Electromagnetic (EM) field distributions, four kinds of structures of STLs, (a)surface
micro-strip, (b)embedded strip, (c)strip with conductive plate and (d)shielded
strip, are compared by experiment and calculation. From the results of
experiment and calculation, the difference of structure between (c)strip and
(d)shield is inconsiderable for the transmission characteristics. The dips of
the resonance frequency are small for (b)embedded at 1 GHz to 2 GHz. It is
cleared that (c)strip and (d)shield are efficient for suppression of EMI by the
measurement results of magnetic near field distributions.
11. EMD2003-70
On the measurement of contact resistance by the non-linear method
John W. McBride (
Standard
methods of measuring contact resistance do not distinguish between constriction
resistance' bulk
resistance and
film resistance. The non-linear techniques are able to separate the constriction
resistance from other resistances.
This paper
looks at the implementation, limitations and applications of the non-linear
method. A test rig has been built for investigation of the behaviour of the
sinusoidal technique with reference to current, force and bulk resistance.
The work
presented here extends the limited measurement current of existing methodology
to a maximum or 24 Amps. The effectiveness of the technique in eliminating
linear (i.e.bulk) resistances from measurements is shown.
The results
are compared to contact theory to justify the effectiveness of the non-linear
technique and its underlying assumptions. Practical refinements of the method
are suggested. The application of the technique to the study of surface characteristics
is discussed.
[Session 3]
--Sliding contacts and connectors--
Chairs:
Liangjun Xu (
12. EMD2003-71
Mechanical and electrical analysis of connector insertion-extraction
phase
N.
Ben Jemaa, A. El Manfalouti, R. El Abdi (
Inside a connector an interface with low
insertion force and contact resistance is required, utilizing low cost
materials such as copper alloys surrounded by tin coating. Relating to the
application, the operating parameters have a wide range of values of currents,
forces and materials.
In this paper, we present a new experimental
method based on non-intrusive probing of the deflection of the spring terminal
with a laser technique. The main feature is that the reflection of the Laser
beam onto the spring allows the determination of the contact force of the
lamella-spring inside the female part. The technique requires the following
insertion parameters during the insertion stroke: contact deflection d,
which allows contact force Fc, insertion force Fi and contact resistance Rc.
It was found that the insertion
force has a maximum value which decreases to the stable value, and depends on
the size and the material of the pin. However contact resistance decreases
sharply when first inserting, and tends to stable values on completing the
insertion process, which is less sensitive to the pin diameter. Furthermore the
final value which is important for the connector characterization is related
and discussed. Finally, discrepancies were observed between the experimental
and calculated data with simple numerical models. More complex models are in
progress, which should improve the convergence of the theoretical approach to
experimental results and proceed to the optimization of the connector
parameters.
13.
EMD2003-72
Application of shadow image processing technique to 3-D observation
of damaged surface profile in sliding contact
Masanari Taniguchi, Hiroyuki Ishida, Tasuku Takagi (
Relationship between sliding effects and damages on sliding contact
surfaces were studied using the digital image measuring system(DIMS) which was
developed by the authors for quantitative analysis on the surface damage. The
shadow image processing technique(SIPT) was applied. By using both DIMS and
SIPT, the surface damage on the contact could be successfully observed as the
3-D images. In this paper, the measure ring systems and the result examples
will be shown..
14. EMD2003-73
Influence of surface roughness on contact voltage drop of sliding
contacts
Takahiro
Ueno, Noboru Morita (Nippon Institute of Technology)
Usually, sliding contact action is used to supply current to a rotating or a moving object and is operated under various atmospheric conditions such as vacuum, low-temperature, low-oxygen environment and so on. In the present experiment, we examined the relation between sliding contacts phenomena and ambient atmosphere conditions. It is confirmed that the contact voltage drop tends to increase in atmospheric pressure conditions comparison with low-pressure environment. From these results, it is estimated that the physically adsorbed gases on the sliding surface and surface roughness conditions affects the contact voltage drop rise. In this paper, the relation between sliding surface roughness and atmosphere gases variation for sliding contact is examined. As the results, it becomes clear that the contact voltage drop changed for various surface roughness conditions in vacuum and inert gases environment. However, in the including oxygen environment, it is obtained experimentally that the surface roughness is difficult to affect the contact voltage drop. Therefore, the effect of ambient gas on contact voltage drop is discussed.
15. EMD2003-74
Characteristics of flat commutator on dc motors for automotive fuel
pumps
Takashi Shigemori, Koichiro Sawa (
Automotive
fuel pumps are driven by small DC motor. Commutation is carried out in
gasoline, and arc voltage and duration are different from that in air. Our
laboratory have analyzed commutation phenomenon in gasoline quantitatively and we
have considered brush materials. To develop high power motor, we need to
examine materials that are less arc abrasion and good sliding condition, in
this research, we attention to commutator materials and shapes, then we research
characteristics to change cylindrical copper commutator for flat carbon
commututor. As a result, it is
possible to drive longer time than copper commutator in spite of arcing
condition.
[Session 4]
--Arc discharges and related phenomena—
Chairs: Yi-Lin Zhou (
16 EMD2003-75
Investigation of arcing damage on connector during hot unplugging in
new 42V automotive powernet
J.Razafiarivelo,
Y.Kuwada (FCI Corp.), L.Morin (FCI
A.
El.Manfalouti (
The
conversion of the power network system voltage from 14 VDC to 42 VDC is
accompanied by a discontinuous change of arcing energy produced during live
intentional or accidental unplugging. It leads to an adaptation of the
electrical breaking and connecting devices. For the connectors, it results in
adding the capability of withstanding the arcing during live disconnection to
the basic ones of high conduction and low insertion effort. To quantify this
new capability and the correlated level of arc damage, the authors propose a
global result that links the insertion criteria “insertion force” to the global
arc parameter “arc energy”. They put forward three zones of arc damage delimited
by arc energy threshold values. As an extension of this result, the outline of
an evaluation method of arc damage on connector is proposed. As intermediate
results, the influence of the opening speed on the arc energy increasing is
confirmed. Moreover, the influence of the erosion mechanism on the conduction
behavior of the contact is investigated. To conclude, a short review of the
different connector concepts is presented.
17 EMD2003-76
Relationship between transition boundary to gaseous phase and
spectrum intensity in Ag break arc
Kiyoshi Yoshida, Atsuo Takahashi (Nippon Institute of Technology)
Arc voltage waveform, arc current waveform, AgⅡ(243.78nm) spectrum intensity, and AgⅠ(328.07nm) spectrum intensity are measured for Ag break arc, under the condition where source voltage E= 6~48V, load inductance L= 0, 2.3 mH , and closed contact current Io= 0.6~6A. Spectrum intensity of AgⅡ(ion) becomes maximum value near the gaseous phase transition point, and it gradually decreases in the gaseous phase. The spectrum intensity of AgⅠ(excited atom) increases until gaseous phase transition point. After the gaseous phase transition, AgⅠ becomes constant value which does not depend on the circuit condition. Furthermore, in the boundary closed current at which transition ratio to gaseous phase is 50%, it is clarified that the average spectrum intensity of AgⅡ has constant value without depending on the circuit condition. Therefore, transition to gaseous phase is made when the mean number of Ag ion in metallic phase exceeds certain value.
18 EMD2003-77
Arc extinction and reignition at a fixed short gap
Keiichi Suhara (Tokyo National College of Technology)
At electric
contact, before complete extinction of arc discharge, a repetition phenomenon
of arc extinction and re-ignition is observed in many cases, sometimes for a long
time and sometimes for a short time. Occasionally, no repetition is observed. From a viewpoint of arc duration, the
period of this repeating arc is also an important factor if it is very long. For the purpose of investigating why
this phenomenon occurs and how long it lasts, the arc extinction current and
the arc re-ignition voltage have been measured. The circuit is, for simplicity, resistive with a capacitor
source voltage and a fixed short arc gap.
Taking the unstable arc region and the load line of the circuit into
account in addition to the measured results, the process of various types of
arc extinction and re-ignition phenomena has become clear.
19 EMD2003-78
Temperature measurements and behavior observations of breaking arc
between copper contacts
Tetsuya Kitajima, Junya Sekikawa,
Takayoshi Kubono (
The purpose of this paper is to observe what effect the
various opening speeds (10mm/s, 20m/s and 30mm/s). A breaking arc is generated
in a DC 42V - 10.5A circuit. The
arc voltage, the arc current and the arc spectrum intensity are
measured. Spectrum wave length 510.55nm, 515.32nm, and 521.82nm are measured at
all of opening speeds. Judging the arc temperature from Boltzman Plot, the temperature
starts from high temperature, ands falls gradually to 4650 -4750K with time,
then the gap length at the arc temperature is 0.68 - 0.86nm on all of the
opening speeds.
20 EMD2003-79
Daisuke Sakai, Yoshiharu Saito, Junya Sekikawa,
Takayoshi Kubono (
Abstract:
Various researches on an arc electric discharge phenomenon have been made.
Although there is much research on
metal electrode, graphite is chosen as a new material of electrode. The arc
root properties (temperature,
current density, radius of an arc root, fraction of current density carried by electrons, evaporation rate etc.) of
graphite and copper are calculated by computer with the cathode-fall voltage as parameter and compare the arc
root properties of graphite with the arc root properties of copper. Compared
with copper, graphite has the features that the thermal conductivity is low and
the evaporating temperature is high.
21 EMD2003-80
Observation of breaking arcs of Ag or Cu electrical contact pairs
with a high-speed camera
Junya
Sekikawa, Takayoshi Kubono (
Breaking arcs occurring between Ag or Cu electrical contact pairs in DC 56V/7A resistive circuit were observed with a high-speed camera (1000frames/s). As a result, the increase of brightness of the arc-emitted light synchronized with the increase of arc current in the latter half of arc duration. For the case of Ag contacts, the brightness increased in entire region of the breaking arc with sudden increase of the arc current. On the other hand, the increase of the intensity for Cu contacts occurred in not only entire discharge region but also anode spot region significantly.
[Session 5]
--Switching devices--
Chairs: H. Nowacki (HARTING KGaA), K.Yoshida (Nippon Institute of
Technology)
22 EMD2003-81
Analysis and experimental investigation of dynamic behavior of AC contactors
concerning with the contact bounce
Chen
Degui, Li Xingwen, Sun Zhiqiang, Tong Weixiong (Xi'an Jiaotong University)
We proposed a new electric contact device that greatly improves arc electrical discharge characteristics. Electric contact functions are divided into energizing and switching. A capacitor is connected in series to a contact for the switching contact. Using two conventional relay contacts, no arc operation was confirmed for 42V/3A make-break operation. Contact resistances were measured for many times operation, and surface of electrodes were observed. A chip capacitor was arranged at one side of the contact electrodes of a twin relay and the possibility of miniaturization was confirmed.
23. EMD2003-82
Relay contact of multi-electrodes with timely controlled operation
Yu Yonezawa, Noboru Wakatsuki (
We proposed a new electric contact device that greatly improves arc electrical discharge characteristics. Electric contact functions are divided into energizing and switching. A capacitor is connected in series to a contact for the switching contact. Using two conventional relay contacts, no arc operation was confirmed for 42V/3A make-break operation. Contact resistances were measured for many times operation, and surface of electrodes were observed. A chip capacitor was arranged at one side of the contact electrodes of a twin relay and the possibility of miniaturization was confirmed.
24. EMD2003-83
Study on the safety evaluation method of the power reed switch
Kenjiro
Hamada, Yoichi Wakabayashi (YASKAWA Controls Co., Ltd.), Sean Koenig (YASKAWA Electric America, Inc.),
Shigeo Umezaki, Shigenobu Kobayashi (National Institute of
Reliability
characterist3cs ye part of the index for Safety Evaluation For this index, an
object is judged based
on
its oriented failure characteristics. The magnetically actuated power reed
switch can exhibit just such failure
characteristics
when it does fail making it a good candidate on the evaluation index for reliability.
It has become a key element in the most stringent category of safety control
systems due to the switch offering very high non-contact reliability and
fail-safe
operation in even the harshest industrial environments subject to electrical
surge and noise.
The
result of the occurrence probability of failure to danger is 2.0 x 10^-10 (number/hour)
from the initial field data
observed.
In view of these facts, switch redundancy and compatibility checking must be
done in order to achieve the desired value of probability to failure rate and it
is in this vein that the authors make a proposal.
[Session 6]
--Contact phenomena (2)--
Chairs: Chen Degui (
25. EMD2003-84
Computer and lab
simulation of particulate effect on electric contact reliability
Xu Linangjun
(
Environmental pollution especially dust contamination is one of the main
causes in electric contact failure. Whatever in manufacture or electric devices
operation, dust contamination is hardly avoided. So to understand the effect of
dust on electric contact reliability has a great significant for quality
control and failure prediction. In this paper, dust particulate effect in
corrosion and physical aspects are discussed. The method to evaluate the level
of dust corrosion and hazard size of particulate are presented.
26. EMD2003-85
Testing method study of contact resistance behavior on contaminated
contact area
Feng
Cuifeng (
Nowadays electronic connectors are widely used in various telecommunication devices. These connectors are easily contaminated because the devices are usually exposed in air. In this paper, the contact resistance behavior on contaminated connector contacts is discussed. In order to evaluate the contact reliability of the contaminated contact, multiple-point test is required in the contact resistance measurement. The results show that the contaminated contact area is a hazard to the reliability of the connector.
27. EMD2003-86
Contact behaviors of new material for micro relays
Terutaka
Tamai (Hyogo University of Teacher Education)
Ag(40wt%)-Pd(60wt%)
alloy has been widely applied to various electromechanical devices as contact material.
On the contrary, in application to the micro relays, failure due to the contact
resistance is caused easily by both growth of oxide film on the contact surface
and low contact force.. To solve the increase in the contact resistance, an
overlay of the thin Au or thin Au-Ag (8-l0wt %) has been used on the alloy, On
the contrary, cleanliness and low hardness of these overlays cause adhesion at
contact interfaces, namely sticking in the relays. The increase in the contact
resistance and the sticking are contrary to each other. In order to eliminate,
these contrary properties, the author has studied improvement of the Ag-pd
alloy with a dopant. In the previous studies, low level of the contact
resistance for both static and dynamic contacts of Ag-Pd with Mg doping found
even if the contact surface was covered with oxide contaminant film. This paper
presents, in the former part, excellent contact resistance and adhesion
behaviors of the Ag-Pd-Mg alloy and their mechanisms, and also presents in the
later part, surface contamination behaviors for organic gases.