Ref: Thyristors SRF.ppt (11/06/2014) EUROTHERM CONTROLS a bc Why Thyristor Power Control Units Rather Than Contactors? l Better Temperature Control - Deliver.

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Why Thyristor Power Control Units Rather Than Why Thyristor Power Control Units Rather Than Contactors?Contactors?

Better Temperature Control - Deliver short bursts to match power demand

Eliminates Temperature Fluctuations - Sense changes in supply and adjust power delivery to prevent power fluctuations

Increased Production - built in diagnostics and partial load failure detection allow preventative maintenance before total failure and costly shut downs of process

Lower Maintenance Costs - no moving parts and plug in design increases heating element Lifetime - reduced thermo-mechanical stress

Process Protection - Current and Power limits protects process and heating elements

Lower Energy Costs - Allows plant wide energy monitoring which reduces peak demand

Ref: P .ppt (10/04/23) 2EUROTHERM CONTROLS

Thyristor Power ControlThyristor Power Control

Will only conduct one way

FiringCircuit

Parallel Pairs

Anode CathodeGate

Thyristor Device

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

ProtectionProtectionSnubber - Resistor/ Capacitor for elimination of spikes and false

triggering particularly on transformer loads.

Fuse

MOV

Snubber

FiringCircuit

Isolation

Eurotherm Thyristor

Unit

ControlCircuit

MOV - Metal Oxide Varistor - Resistance changes on voltage, as voltage rises mainly on spikes it will absorb the excess voltage

Fuse - Protecting against over current draw, will blow faster than the thyristor operates.

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Firing ModesFiring Modes

Logic Burst / Whole Cycle Single Cycle Phase Angle

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Logic Firing - Logic InputLogic Firing - Logic Input

On at Voltage zero.

Off at Current zero.

Logic O/P from controllerTypically Off <2Vdc On >5Vdc

To minimise interference the thyristor unit switches on at the first zero crossing of the mains voltage afterthe the logic input goes On

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Whole Cycle Firing/Burst Firing - Whole Cycle Firing/Burst Firing - Analog I/PAnalog I/P

Cycle Time giving for 50% output

At 50% TON = TOFF

TCYCLE = TON + TOFF

CYCLE

TON TOFF

T

For lesser disturbance on mains you may increase the cycle time

Typical 1 cycle to 256 cycles approx 5 secsLong cycle time can be few mins

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Single Cycle Firing - Analog I/PSingle Cycle Firing - Analog I/P Cycle Time is 2 cycles at 50%

50% Power

33% Power

T

T CYCLE

CYCLE

•Silicon carbide•When element new the resistance is low and full voltage must only be applied for short bursts. •As the elements heat up and or age the voltage can be sustained for longer periods. •To prevent problems on new elements a power limiting must be used otherwise the element can shatter

Ref: P .ppt (10/04/23) 8EUROTHERM CONTROLS

TE 200, TC2000 & TC2001TE 200, TC2000 & TC2001

3 Wire Star 3 Wire Delta

TC2000, TE200

or TC2001

TC2000, TE200

or TC2001

Less Expensive than three leg control but when the unit is off the non-controlled leg is at line potential

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Phase Angle - Analog I/PPhase Angle - Analog I/P

Firing equally delayed for each 1/2 cycle

Shown as 50%

Not widely used in Europe as there are problems with CE requirements.

On

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

Load TypesLoad Types

Fixed Resistance - Any firing mode Variable Resistance - Current limit or

single cycle Transformer Coupled - Phase angle or

burst firing with delayed start. This reduces surge currents. Will switch on at zero crossing point of current.

Inductive as above

Ref: P .ppt (10/04/23) 11EUROTHERM CONTROLS

Load TypesLoad Types

Ref: P .ppt (10/04/23) 12EUROTHERM CONTROLS

Single Phase - Constant Load ResistanceSingle Phase - Constant Load Resistance

SSDS / RSDA TE 10S TC1027425S / 450

Ref: P .ppt (10/04/23) 13EUROTHERM CONTROLS

Single Phase - Variable Load ResistanceSingle Phase - Variable Load Resistance

TE10A 425A 460 TC1028

Ref: P .ppt (10/04/23) 14EUROTHERM CONTROLS

Three Phase - Constant Load ResistanceThree Phase - Constant Load Resistance

RS3DA / RS3AA TE200S / TE200A TC2000 TC2001

TC3000

TC300

Ref: P .ppt (10/04/23) 15EUROTHERM CONTROLS

Three Phase - Variable Load ResistanceThree Phase - Variable Load Resistance

TC2001

TC3001

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

ContinentalContinental

SSDA RSDA RS3DA

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

TU SeriesTU Series

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

TC SeriesTC Series

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

TE10S / TE10ATE10S / TE10A

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

450 / 460450 / 460

Ref: Thyristors SRF .ppt (10/04/23)

EUROTHERM CONTROLS

425S / 425A425S / 425A