52nd IEEE Holm Conference on Electrical Contacts steel 22 CC&CE AXICOM Relays Contacts Galvanically...

Communications, Computer & Consumer Electronics Business Unit

AXICOMAXICOM

The Design Challenges Involved in Miniaturization of Electromechanical

Relays

Dr. Werner Johler

Tyco Electronics AXICOM

Switzerland

52nd IEEE Holm Conference on Electrical Contacts

2CC&CE

AXICOM RelaysAXICOM Relays

Characteristics Telecom / Signal Relays

•Low contact resistance [m ]

and high insulation

resistance [M ]

•High insulation > 2500V

– Between open contacts

– Between load and control

circuit

•Switching range from µV to

250V and nA to 5A

•Resistant against

electromagn. interference

•Robust against

– over-current

– over-voltage

– over-temperature

•Reliable even in harsh

environment

•Linear characteristic

•Good RF characteristics

•Easy to use

•Cost effective

3CC&CE


Overview

I Introduction

II Miniaturization

III Relay Protection

IV Contact Reliability in Miniaturized Relays

V Isolation, Dielectric and Surge Characteristics

VI Thermal Limitations

VII Alternatives to Electromechanical Relays

VIII Conclusions

4CC&CE


Challenges to Relays in Electronic Circuits

•extremely low loads with

– voltages - µV, but also 1500 Vrms

– currents – nA, but also 500 A

• load and monitoring circuits in parallel in the same

switching devices

• load and monitoring circuits in sequence during the

lifetime of the relay

•high and low temperature exposure

•higher reliability and increased safety requirements

•zero defect expectation

5CC&CE


Relay - Requirements

control unit / magnet system contact side / contact system

relay

mechanical resistance(shock, vibration,..) processing

(solderbilityt, terminal planarity, ..)

contact load(current/voltage)

life time(electrical/machanical)

enviroment(climate,gas,detergent..)

temperatureisolation system(dielectric strength,isolation resistance)

Volume, PCB-space-(lxhxw)

sound emission

power supplier

cost/price

tim e

contact resistance

6CC&CE


Miniaturization of Telecom Relays

339

1050

2200

7133

60

112.5

200

457

100

30

10

5

1

10

100

1000

10000

1G - 1965 2G -1980 3G - 1990 4G - 1999 5G

Vo

lum

e [m

m3]

1

10

100

1000

Bo

ard

spac

e [m

m2

] /

To

lera

nce

[µ

m

Volume [mm3] Boardspace [mm2] Tolerance [µm]

?

7CC&CE


Key Characteristics

140140150Coil power [mW]

13011085Thermal res. [K/W]

3/35/57/6Op./rel. time [ms]

2500

1500

2500

1500

1500

1500

Surge Coil– contacts

Contacts

223Max .cont. current [A]

220/250220/250220/250Max. cont. voltage [V]

60 / 62.560 / 62.560 / 62.5Load power [W/VA]

1.5 - 242 – 483 – 48Coil voltage [V]

10 x 6 x 5.6515 x 7.5 x 1020 x 10 x 11Dimensions [mm]

4th Generation3rd Generation2nd Generation

8CC&CE


Relay - Elements

Housing - Protection

Actuator – Magnetic circuit

Spring set – Contact system

9CC&CE


Actuator

•small in size

•low-power consumption

•high-force and high-displacement

•similar characteristics than springs

•ability to store energy for bistable (latching)

switching characteristic

•highly efficient

•high-speed of operation

10CC&CE


Actuator Principles

Linear force-displacement-characteristic

Force

Powerdissipation

Conclusion Coil heating Small displacement

Electromagnetic

Actuator

Electro-

static

Piezo-

electric

F

d

F

d

F

d

Thermal

F

d

F k d U c d* * *31F k I c d* *2

P I~ 2P V~ /1 0 0

F ANI

d0

2

2* * F A

V

d0

2

2* *

11CC&CE


Non polarized Magnetic circuitp

0

4

8

12

16

20

24

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Armature travel (mm)

Sp

rin

g s

et-

arm

atu

re-

forc

e (

cN

)

operate V

release V

12CC&CE


Polarized Magnetic Circuit

Armature

Permanent Magnet

Coil

YokeS

N

13CC&CE


Polarized Magnetic Circuit

Armature

Permanent Magnet

Coil

Yoke

SN

S

14CC&CE


Polarized Relay

-16

-12

-8

-4

0

4

8

12

0 50 100 150 200 250

Armature travel (my)

Arm

atur

e fo

rce

(cN)

0 V

release V

nom V operate V

contact set

15CC&CE


Coil Arrangement

Standard Coil Flat Coil

16CC&CE


Spring set – Contact system

• large contact distance and high insulation resistance in the

open condition

•high contact force and low contact resistance in the closed

condition

•optimum relative movement during contact closing

•high contact opening force

•minimum contact bouncing during contact closing and

opening

•provide the necessary insulation between open contacts,

between adjacent contacts and between coil and contacts

•high resistance against mechanical shock and vibration

17CC&CE


Contact Gap

Sensitivity

Initial End of Life

Dielectric & Surge

Size of Relay

19CC&CE


Plastics

PBT

PPO

PPS

PEK

LCP

PAI

PET

PP

PA6/66

PE-LD

PI

PC

PMMA

SANPVC

PS

High Performance

(HDT > 150°C)

Technical Polymers

(HDT = 100 - 150°C)

Commodities

Pri

ce

/ P

erf

orm

an

ce

amorphous semicrystalline

PEIPES

PPAPSU

SAN ABS

PA 46PAR

Plastics Pyramide

PE-HD

FP

PE UHMW

LFT

POM

COC

20CC&CE


Copper Materials

200 300 400 500 600 700 800 900 1.000

Ele

ctr

icalco

nd

ucti

vit

y(M

S/m

)

Ele

ctr

ica

lc

on

du

cti

vit

y(%

IA

CS

)

Rp0,2 (MPa)

0

10

20

30

40

50

10

20

30

40

50

60

70

80

90

100

0

1.100 1.200

CuZn15 M15

CuSn0,15 K81CuCrAgFeTiSi K88

CuCrSiTi K75

CuFe2P K65

E-Cu K32SE-Cu K14

CuNi18Zn20 N18CuNi9Sn3 L49

CuNi3SiMg K55

CuSn3Zn9 S12

CuZn30 M30

CuSn4 B14CuZn23Al3Co S23

CuSn8 B18

CuNiSi C19010

K57

CuNi1SnP C19025

CuBe2 C172

CuTi3 C199

Edelstahl X12CrNi177

21CC&CE


Permanent Magnets

Year

En

erg

y D

en

sit

y

Ferrite

steel

22CC&CE


Contacts

Galvanically spot platted

contacts

Multilayer contact -

welded

0.35 mm

0.1

35

mm

Precious metal = 4 µm Precious metal = 55 µm

24CC&CE


Overview

I Introduction

II Miniaturization






VIII Conclusions

25CC&CE


Protection of Relays IEC 61810-7

• RT 0 unenclosed: not provided with a protective case

• RT I dust protected: provided with a case which protects its

mechanism from dust

• RT II flux proof: A relay capable of being automatically soldered with

no migration of solder fluxes beyond the intended areas.

• RT III: wash tight: A relay capable of being automatically soldered and

subsequently undergoing a washing process to remove flux residues

without allowing the ingress of flux or washing solvents

• RT IV sealed: A relay provided with a case which has no venting to the

outside atmosphere and having a time constant better than

2 x 104 s.

• RT V: hermetically sealed: A sealed relay having an enhanced level of

sealing assuring a time constant better than 2 x 106s.

26CC&CE


Contamination

•Sealed housings protect relays from external

contamination but

•Internal contamination

–Particles

–Oil and grease from production

–Silicon

–Outgassing products from insulating materials

27CC&CE


Particles – Critical Size

contact

contact

particle

0 10 20 30 40 50 60

contact force [cN]

0

2

4

6

8

10

12

14

part

icle

siz

e[u

m]

28CC&CE


Impact Ambient Temperature

CH02.167

Konta

ktw

iders

tan

d[O

hm

]

1000 Schaltungen

0 85 170 255 340 425

-3 10

-2 10

-1 10

0 10

1 10

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

0

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

Number of operations [thousands]

Conta

ct R

esi

stance

[O

hm

]

CH02.167

Konta

ktw

iders

tan

d[O

hm

]

1000 Schaltungen

0 85 170 255 340 425

-3 10

-2 10

-1 10

0 10

1 10

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

0

Leer

150

C

Pro

be

Raum

80

C

100

C

120

C

150

C

Number of operations [thousands]

Conta

ct R

esi

stance

[O

hm

]

29CC&CE


Outgassing of Insulating Materials

initial

Magnetic wire

optimized initial

Plastics

optimized0

200

400

600

800

1000

ou

tga

ssin

gra

t e[p

pm

]

120°C 200°C 250°C

30CC&CE


Gastight/Hermetically Plastic Sealed Relays

•Lifetime of 25 years must be met

•50% of the initial filling at the end of life

•Survival of 3 times SMD soldering processes –

peak temperature 260°C

31CC&CE


Gas Penetration Plastics

A B C D E

plastic material

0

20

40

60

80

100

120

ga

sp

erm

ea

bil

ity

(a

rbit

rary

un

its

)

N SF 2 6

32CC&CE


SF6 Partial Pressure

0 100 200 300 400 500

time ( years )

0

10

20

30

40

50

60

70

80

90

100

SF

-p

art

i alp

res

su

r e(

kP

a)

6

25

93

35CC&CE


Integrity of Plastic Housings

• Stress during soldering

– SMD soldering process

• Stress during relay life

– Thermal endurance

– Damp heat

– Rapid change of temperature

– Pressure storage

– Temperature cycle IEC60950

– Climatic sequence

initial final c-c no nc0

20

40

60

80

100

conta

c tre

sis t

anc e

(m

Ohm

)

1

2

3

4

5

die

l ect

r ic

withst

and

voltage

(kV

)

0

p

Rapid change of temperature

36CC&CE


SMD Soldering – Lead Free Process

0 50 100 150 200 250 300 350 400 450 5000

50

100

150

200

250

300

tem

per a

tur e

[°C

]

37CC&CE


Pressure = f(temperature)

Theory

Reality

Humidity

Outgassing products

plastics

magnetic wire

resin

Additional pressureincrease

pressure

sensor

oven

DUT

..

constT

Vp

38CC&CE


0 50 100 150 200 250 300 350

temperature [°C]

0,5

1

1,5

2

2,5

3

3,5

4

pr e

ssu

r e[ b

ar]

theory

poormaterialsand/ormoisture

theoryoptimizedmaterialsand dry components

Pressure = f (temperature)Optimized Situation

Outgassing products- Pressure increaseMoisture- Pressure increase

39CC&CE


Water vapor transmission of plastics

Oxygen Permeability [cm3 mm/m2 day bar]

Water Vapor Transmission Rate [g mm /m2 day]

��

��

��

��

��

��

0,001 0,01 0,1 1 10 1000,001

0,01

0,1

1

10

100

LCP

HDPE

PCTFE

PET

Nylon 6

PVDC

40CC&CE


Impact Humidity

��

��

� � ��

0 200 260 440

time in [s]

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

inte

rna

l pre

ssu

re in

cre

ase

[mb

ar]

Manufa

ct.

14d@

23°C

-50%

r.h.

Dry

pack

14d@

55°C

-95%

r.h.

14d

@55°C

- 95%

r.H

.

ESD

bag

14d

@55°C

- 95%

r .H

.

��

��

� � ��

0 200 260 440

time in [s]

40

60

80

100

120

140

160

180

200

220

240

260

280

t em

pe

rat u

rein

[°C

]

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

inte

rna

l pre

ssu

re in

cre

ase

[mb

ar]Initial

43CC&CE


Overview

I Introduction

II Miniaturization






VIII Conclusions

44CC&CE


Contact Materials

•Gold - layer

– Au

– AuAg 8 ... 10

– AuNi 2 ... 5

– AuPd 2 ... 4

– AuCo 0.2 .... 0.5

•Contact - layer

– AgNi 10 ... 20

– AgPd 60

– PdRu 10

– W

– Ru

AgPd 60

Cu Ni 30 Fe

AuAg 8

0.3 mm

0.1

33

mm

Ag Ni 20

Cu Ni 30 Fe

AuNi 2

0.3 mm

0.1

4m

m

47CC&CE


Gold Based Contact Materials

•Deposition process

– Sputtered gold layers

– Rolled gold layers

– Electro deposited gold layers

Standard

Annealed

– Cleanness of Contacts

– Relay Manufacturing

48CC&CE


Welding Process – Resistive Welding

Cu electrode

Cu electrode

Base material

Contact

profile

50CC&CE


Low Contact Force

0 500 1000 1500 2000 2500

Number of operation [thousands]

0.01

0.1

1

10Contact circuit resistance [ohm]

Fc = 2 cN Ambient = Air

0 500 1000 1500 2000 2500

Number of operation [thousands]

0.01

0.1

1

10Contact circuit resistance [ohm]

Fc = 2 cN Ambient = SF6

51CC&CE


Material transfer

Dielectric and surge

Endurance Timing

Operate & Release

Sticking & Bridging

52CC&CE


Reqiurements for Switching Contacts in Telecom / Signal Relays

–Low and stable contact resistance

–High resistance against welding during

switching electrical load

–No or minimum material transfer/forming of pip

and crater during DC switching

–Low contact erosion

–Low contact material thickness

–Low cost

53CC&CE


Test Samples

•Hermetically sealed - plastic relay

– Defined switching atmosphere

N2

SF6

Any Mixtures of gases

– Time constant better 1011 s

– Lifetime > 25 years

– Pressure and characterisiticsnot depending on altitude

54CC&CE


Contact Material – Switching atmosphere

Cu

5µm W or Ru1.5 µm Au

0.35 mm

0.1

35

mm

W and Ru have a high tendency towards oxidation

Inert switching atmosphere required (N2, SF6 etc.)

1.5 µm Au

0.35 mm

CuNi 30

25 µm

0.35 mm

CuNi 30

55 µm AgNi 20

55CC&CE


•Contact loads

– 125 V/0.24 A - 30 W resistive

– 24 V / 1.25 A - 30 W resistive

– Cable load open end 10 m/48 V

– No load and CC0 test ( 30mV/ 10mA)

•Number of operations:

– 500 000 resistive loads

– 1 600 000 cable load

•Contact material / Atmosphere

– Ru + Au in 100% N2

– Ru + Au in 100% SF6

– W + Au in 100% N2

– W + Au in 100% SF6

Experimental Parameters – Telecom Relays

56CC&CE


0 100 200 300 400 500

number of operation [thousands]

0,01

0,1

1

10contact circuit resistance [ohm]

PdRu10 + Au in SF6- 125 V/0.24 A

0 100 200 300 400 500


0,01

0,1

1


Ru + Au in N2- 125 V/0.24 A

0 100 200 300 400 500


0,01

0,1

1


Ru + Au in SF6- 125 V/0.24 A

0 100 200 300 400 500


0,01

0,1

1


W + Au in N2- 125 V/0.24 A

Electrical Endurance 125 V / 0.24 A

0 100 200 300 400 500


0.01

0.1

1


W + Au in SF6- 125 V/0.24 A

AgNi20+Au-N2

AgPd+Au-N2

PdRu10+Au-N2

PdRu10+Au-30%SF6

PdRu10+Au-SF6

Ru+Au-SF6

Ru+Au-N2

W+Au-SF6

W+Au-N2

contact material and ambient gas

0,01

0,1

1

conta

c tre

sis t

anc e

[ Ohm

]

57CC&CE


AgNi 20 + Au

100%N2

Make and Break - 125V/0.24A - 30 W

AgPd 60 + Au

100%N2

PdRu 10 + Au

100% SF6

W + Au

100%N2

W + Au

100% SF6

W + Au

100% SF6

Ru + Au

100% N2

Ru + Au

100% SF6

Contact Erosion – 125V / 0.24V

58CC&CE


Material Transfer 125V/0.24A - 30 W

Make and Break AgNi 20 + Au in 100%N2

59CC&CE


Material Transfer 125 V/0.24 A

AXICOM Communication Relays

0

20

40

60

80

100

120

-20

-40

-60

-80

-100

-120

Ma

xim

um

de

pt h

of

ero

sio

n[u

m]

An

od

eC

ath

od

e

AgNi20+Au

100% N2

bre

ak

+

ma

ke

ma

ke

bre

ak

AgPd60+Au

100% N2

bre

ak+

ma

ke

ma

ke

bre

ak

PdRu10+Au

100% N2

bre

ak

+

ma

ke

ma

ke

bre

ak

PdRu10+Au

30% SF6

bre

ak

+

ma

ke

ma

ke

bre

ak

PdRu10+Au

100% SF6

bre

ak

+

ma

ke

ma

ke

bre

ak

bre

ak

+

ma

ke

ma

ke

+

bre

ak

Ru+Au

SF6 N2

bre

ak

+

ma

ke

ma

ke

+

bre

ak

Ru+Au

SF6 N2

60CC&CE


Sticking Contacts 125 V/0.25 A

NC

M&B

NC

Mak

e

NC

Bre

ak

NO

M&B

NO

Mak

e

NO

Bre

ak

0

20

40

60

80

100

sti

ck

ing

co

nta

ct s

[%]

W+Au-N2 W+Au-SF6 Ru+Au-N2

Ru+AuSF6 PdRu10+Au-100%SF6 PdRu10+Au-30%SF6

PdRu10+Au-100%N2 AgPd60+Au-100%N2 AgNi+Au-N2

64CC&CE


Overview

I Introduction

II Miniaturization






VIII Conclusions

65CC&CE


Isolation System Relay

•Coil to contacts

–Solid + gaseous

•Open contacts

–Gaseous

•Adjacent contacts

–Solid + gaseous

66CC&CE


Isolation

•Defined by

– Isolation resistance @ 500VDC

– Dielectric AC or DC

– Surge

– Clearance and creepage distances

•Depends on

– Distance

– Geometry

– Material / gas type

– Pressure

– Humidity

67CC&CE


Isolation, Dielectric and SurgeCharacteristics

•Telecom relays must be capeable to withstand

– 2500 V surge voltage (2 /10 µs)

– 1500 Vrms – 1 minute

– 500 A pulse current (8 /20 µs)

– Continuous current of 60A / 5s

69CC&CE


Dielectric and Surge

0,001 0,01 0,1 1 10 100 1000

pressure x electrode distance ( 100 kPa . mm )

0,1

1

10

100

1000

die

lec t

ric

withst

and

voltage

(kV

)

N2SF6

0,2

2,51,5

0,6

70CC&CE


Dielectric and Surge – 4G relay

nc1 nc2 no1 no2 c-c nc1 nc2 no1 no2 c-c0

1

2

3

4

5

die

lec

tric

wit

hsta

nd

vo

ltag

e(

kV

)

N2 SF6

71CC&CE


Isolation –Application

IEC 60950 IEC 60335-1 IEC 60730-1

EN 60950temperature cut-outs.

household and similar thermostats and

business equipment electrical applliances similar controls.

b + s b + s b + s

double insulation

contact- coil- contact- coil- contact- coil-

consisting side side side side side side

basic-insulation 1.5 kV 1.5kV 1.25 kV 2.5kV 2.0 kV 2.5kV

plus

supplementary

insulation min. 0.4mm min. 1mm min. 1mm

r r r

1.5kV 3.75kV 4.0kV

reinforced

insulation

min. 0.4mm min. 1mm min. 1mm

if no mechanical stress min. 2mm min. 2mm

b + s b + s b + s

basic-insulation

plus

1.5kV 2.5kV 2.5kV

supplementary 1.5 kV 1.25kV 2.0kV

insulation 1.5kV 2.5kV 2.5kV

with two layers

r r r

reinforced

insulation

3.0kV 3.75kV 4.0kV

with 3 layers

(or 2 layers)

3.0kV

reinforced insulation compromises three layers of insulation

material for which all combinations of two layers together

pass the electric strenght test for reinforced insulation.

creepage distances/

clearances between 5/4mm 8/8mm 8/6mm

contact and coil

The statet CTI-value

is valid for these IIIa / IIIb > 250 > 250

plastic parts which

bear terminals

IEC/EN 60950Business Equipment

IEC/EN 60335-1Household a. similar

IEC/EN 60730Temperature cut outs

72CC&CE


Isolation, Dielectric and SurgeCharacteristics

– The insulation of a gaseous isnulation can be increased by

Bigger gap

Higher pressure

Better insulating gas

– Gastight relay housings enable the use of better insulating gases such as SF6 which results

reduction of contact gap

increases the capability of the whole isolation system

73CC&CE


Overview

I Introduction

II Miniaturization






VIII Conclusions

74CC&CE


Thermal Limitations

•Relay parameters are temperature depending

•Thermal resistance is increasing with smaller

designs

•Relays are used in higher ambient temperature –

engine compartment

•Materials are suitable only for a certain

temperature range

•Safe operation required, even hot start

75CC&CE


2nd - 4th Generation - Miniaturization

Volume

Surface

Thermal

resistance

0

500

1000

1500

2000

2500

2G 3G 4GRelay Generation

Vo

lum

e [

mm

3]

/ S

urf

ace

[m

m2]

0

20

40

60

80

100

120

140

Th

erm

al

Re

sis

tan

ce

[K

/W

]

76CC&CE


Coil operating range – Physical Dimensions

Urel

Uop

2G max.125°C

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Ambient Temperature [°C]

Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

3G max.125°C2G max.125°C

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

4G max.125°C

3G max.125°C2G max.125°C

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

4G max.150°C

4G max.125°C

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

77CC&CE


Operating Temperature Range – Coil Power

Urel

Uop

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

80mW - 0A

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

80mW - 0A

140mW -0A

200mW - 0A

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

78CC&CE


Operating Temperature Range – Current

Urel

Uop

140mW -0A

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

140mW -0A140mW-

2x1A

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

Urel

Uop

140mW -0A

140mW-

2x2A

140mW-

2x1A

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

2,2

2,4

2,6

2,8

3

3,2

3,4

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120


Co

il o

pe

rate

vo

lta

ge

[U

/U

N]

79CC&CE


Coil operating range – Latching Relays

Non latch

100mW

Non latch

200mW0

1

2

3

4

5

6

7

8

9

10

11

12

13

-60 -40 -20 0 20 40 60 80 100 120 140


Co

il v

olt

ag

e [

U/U

N]

Non latch

100mW

Latching

100mW-5%

Non latch

200mW

Latching

200mW-5%

0

1

2

3

4

5

6

7

8

9

10

11

12

13

-60 -40 -20 0 20 40 60 80 100 120 140


Co

il v

olt

ag

e [

U/U

N]

Non latch

100mW

Latching

100mW-5%

Non latch

200mW

Latching

200mW-5%

Limiting

voltage

0

1

2

3

4

5

6

7

8

9

10

11

12

13

-60 -40 -20 0 20 40 60 80 100 120 140


Co

il v

olt

ag

e [

U/U

N]

80CC&CE


Thermal Limitations – Telecom / Signal Relays

•Smaller deisgns have a higher thermal resistance

and a smaller area of safe operation

•Self heating of the coil results in considerable

temperature increase

•Higher current has the major contribution to the

self heating

•Better materials allow an increase of the maximum

permitted relay temperature

•At high ambient temperatures the use of latching

relays is strongly recommended

81CC&CE


Overview

I Introduction

II Miniaturization






VIII Conclusions

82CC&CE


Comparison - AlternativesElectro-

mechanicalTelecom/

Signal Relay

MEMSRelay(SiR)

ReedRelay

Transis-tor

SolidStateRelay(SSR)

Opto-coupler

On Resistance very low medium low high high high

Off Resistance very high very high very high low low high

Galvanic separationcontrol – loadload circuit

yesyes

yesyes

yesyes

nono

yesno

yesno

Leakage current no no no yes yes yes

Dielectric/Surge very high medium medium low high high

DC switching yes yes yes yes yes yes

AC switching yes yes yes no yes no

Linearity yes yes yes no no no

Resistance tooverload

very high average average low low low

Resistance toexcess temperature

very high high high low low low

Resistance to EMI high average high low low low

Control power medium very low medium very low medium low

Board-space medium low medium very low high low

Switching frequency medium medium medium very high low very high

Noise, electromagn. medium low medium very low very low very low

Noise, acoustic high low medium low low low

Endurance medium high medium very high very high very high

Cost medium medium high very low high low

83CC&CE


Overview

I Introduction

II Miniaturization






VIII Conclusions

84CC&CE


Development of Relay Technology

•Smaller size – better performance enabled by

– FEM (Finite Element Method)

– maximum efficiency permanent magnets

– efficient magnetic circuits based on the see-saw principle

– flat coil technology for miniaturized design

– overmoulded coils and ENG (Electro-Negative Gases)

technology

– miniaturized multilayer contacts with sputtered gold surfaces

– low outgassing and high-temperature insulation materials

85CC&CE


Innovations Telecom/Signal Relays

•Miniaturization is driving relay innovations

•Miniaturization results in

–Reduced contact forces

–Reduced contact break forces

–Reduced over travel

•Miniaturized relays capable to provide

–Unchanged switching characteristic

86CC&CE


Innovations Telecom/Signal Relays

•Gas tight plastic sealed housings enables

–use of inert and higher insulating gases

–higher insulating gases e.g. SF6 enablesreduction of dielectric distances

•Minimizing the contact erosion allows

–reduce the initial contact gap

–Enable the use of best combination of contact material and ambient gas

–further reduction of the size of electromechanical relays

52nd IEEE Holm Conference on Electrical Contacts steel 22 CC&CE AXICOM Relays Contacts Galvanically...

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Transcript of 52nd IEEE Holm Conference on Electrical Contacts steel 22 CC&CE AXICOM Relays Contacts Galvanically...