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