Relay Basics TYCO.pdf_ (1_1)

8/22/2019 Relay Basics TYCO.pdf_ (1_1)

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General Purpose Relays EMEA Relay_Basics0900 Page 2

Schematic Application Sketch

- Electrical controlled switch

- Controlling of heavy load with low control energy

- Galvanic separation between control and load circuit


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Technical Requirements

Purpose Aspects Realised by

The main function... Control of Contact number Contactselectrical energy and dimensions

The consequence... Separation of Protection class Insulationcontrol and load creepage/clearence

The need... Amotor to Voltage Coil

operate with the DC / ACcontrol signal

The interface... Electrical PCB, Plug in Pinconnection configuration

The conditions... Adaptation to Space, packing, Dimensions

surrounding ambient temperature


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Block Diagram

Relaycoil

Galvanicseparation

Input

Primary Side Secondary Side

Output

Contacts

Control:Coil voltage

Intermediate signal:Magnetic circuit

Contactswitchingvoltage/current


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Application Areas

Electromechanical Relays

Telecom Automotive General Purpose

Current:

Voltage:

Coil:

Insulation:

Load:

High lights:

low high low to high

low low low to high

DC DC DC or AC

low low high

well defined well defined huge range of different loads

small tough able to switch mains voltage


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Typical Application Area

Switching Current [A]

Voltage[V]

10 -2

10 3

10 2

10

1

10 -1

10 -1 1 10 1 10 2

Signal

Relays

Contactor

s

General PurposeRelays

General Purpose Relays:

Load range:

5V DC ... 300V DC5V AC ... 230 / 400V AC

0.1A ... 30A


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Principal Designs

Method of connection: Plug in (need a socket) or

PCBPCB


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monostable bistable

DC-systems AC-systems

Magnetic Systems - Coils


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one coiloperated UA1-A2 = Uinreleased UA1-A2 = 0V

low power consumption 0.2 -0.7W

Monostable Relays Bistable Relays

one or two coils

SET: UA2 (-) / A3 (+)

RESET: UA1(-) / A3 (+)

Hold by permanent magnet or remanent core

DC - Relay Systems


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Bistable Polarized Relays Bistable Remanent Relays

one or two coils

SET: UA2 (-) / A3 (+)

RESET: UA1(-) / A3 (+)

low power consumption approx.0.4W

one or two coils

SET: UA2 / A3 (+-/-+)

RESET: UA1 / A3 (-+/+-)

high power consumption 1.2W

DC - Bistable Relay Systems


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Operating Voltages -Terms

UMAX

UNominal

UPull-in

UNon-operate UHold

URelease

Relay OFF state

Relay On state

Relay in a not specified state

UCoil[Volt]


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Coil Operating Range

Voltage range depends

on ambient temperature

0%

100%

200%

-40 -20 0 +20 +40 +60 +80

Am bient tem perature [ C ]

Coil

voltage[%

ofV

nominal

Vma x

E =Vn o m

E =0

Vopera te

V re lease

Vho ld

O perat ing range

D ro p-o ut ra n e


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Electrical Contact, Designation

ContactNumber Designation D GB USA Symbol

Make ContactNormally Open Contact (N/O)Schlieer

1 A SPST-NO

Break ContactNormally Closed Contact (N/C)

ffner

2 B SP

Changeover Contact (C/O)Double ThrowWechsler

21 CC/O orSPDT

Single Pole

Double Make (D/M)Brckenschlieer

XSPST-NO

DM

Make ContactNormally Open Contact (2N/O)Schlieer

2A 2SPST-NODouble Pole

All other configuration like1pole possible


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Influences on Electrical Contact

Influences Parameters Effectelectrical current

voltageheating, melting, material migration, chemicalreactions, fritting, electrical discharge, contactresistance

thermal arc melting of contact material, material migrationmechanical friction

pressuredeformation, wear, cold welding, contact resistance

ambientconditions

dustgases

increased wear, particles, formation of chemicallayers an corrosion

chemical oxidation contact resistance, inorganic and organic layers,corrosion

z

z

z

z

z

z

z

z


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Influences on Switching ContactDepending on Load Range

Load rangedry circuit


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Electrical Arc

LoadR Contact

current

Supply voltage

U

RArc


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Electrical Arc - Effects with Ag Contacts

No ignition of Arc

Cannotm

aintainArc

00

0.5 1.0 1.5 2.0 2.5 3.0Switching Current [A]

10

20

30

40

50

60

SwitchingVoltage[V]

Stable Arc

Arc extinguishes

0.3

0.1

0

Conta

ctDistance[mm]


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DC Breaking Capacity

10

100

1000

0,1 1 10

500 W

10 W

20 W

100 W

50 W

200 W

DC Load Voltage [V]

DC Load Current [A]


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Typical Loads for General Purpose Relays

q Cooking plates, oven heatingsq Heatings, valves and motors in washing machines and dish washers

q Compressor motors for refrigerator or air condition

q Valves, ignition transformers, pumps in oil or gas heating systemsq Building control: several lamp loads, elevators, rolling shutters


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Capacitive Load

I=U

Re -t/T= RC rise time in ms

Preferred contact material:

DC-Loads AgSnO, AgNi90/10AC-Loads AgSnO, AgNi90/10

t

U,I

Ipeak

U

Capacitive AC-LoadsCapacitive DC-Load

U

R C

U

Load I

I,U

t

UI

Delay of voltage rise


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Inductive Load

I= UR(1-e-t/T)

=RL rise time in ms

Preferred contact material:

DC-Loads AgNi, (AgSnO)AC-Loads AgCdO,AgSnO

$UF


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Load Characteristics

Incandescent

Lamp Load II/IN=10-15

Capacitive

Load II/IN=20-40(-100)

Motor

Load II/IN=5-10

SolenoidLoad II/IN=(3)-10-20


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Relay Switching Behaviour


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Contact Lifetime

Main influences:- Switching current

Parameter:- Load voltage

- Inrush current

- Power factor

- Ambient temperature

- Switching cycle 0 1 2 3 4 5 6S w i t c h i n g c u r r e n t [ A ]

1.0E+04

1.0E+05

1.0E+06

1.0E+07

Operations


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Reduction of Lifetime at inductive AC-Loads

Reductionfacto

rF

Powerfactor cos

1 0,8 0,60,9 0,7 0,5 0,4 0,3 0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9


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Range of Application for Different Contact-Materials

Current A

10-1 1 1010

-310

-210

ContactMaterial

AgNi 0.15

AgNi90/10

AgCdO

AgSnO

AuApplication range of differentcontact materials overlaps

Choice of contact material is optimizedaccording to relay construction


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Strength of Contact-Materials

Load Character AgNi0,15 AgNi 90/10 AgCdO AgSnO2

DC resistiv ++ +DC-inrush ++DC-inductiv ++ +DC / AC-low level ++ +AC-medium + + ++ +AC-heavy + ++ +AC-inrush ++AC-inductiv + ++ +

Enviromental aspects 0 0 -- 0


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Application Range Silver Alloy Gold Plated

Switchin Current A

Voltage[V

]

10

2

10

1

1 1010-3

10-2

10-1

10-2

10-1

- Suitable for low level loads

- Limited use at main loads accordingbase contact material

Grey range:No electrical wear

White range:Permanence of gold platingdepends on number of operations


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Insulation Terms and Classification

Insulation characteristic Purpose Basic insulation Insulation for : Contact-contact in one circuit Insulation between different contact

circuitsInsulation Class 0 and Class 1 between : - Control and load circuit

Supplementary insulation together

with basic insulation Double insulation Reinforced insulation

Insulation Class II for :

Protection against electrical shock Safe separation of load and control

circuit at safety extra low voltage


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Insulation Terms and Classification

Contact behaviour Purpose

Relays with

micro contact gap

Switching of load,

under insulation aspects the load circuit is tosee like closed

Air-gap relay, cut-off relay

(3mm contact gap)

For separation of load

and voltage supply

Safety relays Defined behaviour in case of failure


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Insulation Requirements

Insulation is determined by appliction standards and depends on

q Length of clearence

q Length of creepageq Material data (CTI = Comparative Tracking Index)

q Environmental influence / polution degree

q Control and load voltages


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Safety Relays

N.O. and N.C. contacts shall not close at the same time also when a spring breaks

Normal relay Safety relay


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Safety Relays

N.O. and N.C. contacts shall not close at the same time when N.O. is welded

Normal relay Safety relay

> 0,5mm

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Relay Basics TYCO.pdf_ (1_1)

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