Transcript MICE Decay Solenoid Quench Detector

MICE Decay Solenoid
Quench Detector
Trevor Hartnett
Daresbury Laboratory
Outline
• Existing (PSI) Quench detection system
– How it works
– Why we want a replacement
• Replacement (DL) Quench detection system
– Comparison with existing system
– How existing system could meet other
requirements
• Progress report
– When it will be ready
Existing (PSI) system
• System overview
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3 Crates
Quench Detector
Power Supply
Battery back-up
Quench detection
7 Amplifier
cards
7 Relay
cards
Latch and LED
driver card
Test points
How a quench is detected
Voltage Tap Input
Amplified
Isolated
• 3 Voltage taps
• Resistive measurement
• Central tap amplified
• Outer voltage taps to
provide reference
• Signal is isolated from
the magnet
Quench Triggered
Relay de-energised
Compared
• Relay chain open circuit
• Magnet Circuit breakers
opened
• If signal is outside of
the specified range
• System Latched in the
quenched state
• Window comparator
used to compare signal
Power Supply
Linear power supply
Switch mode ±15V and
12V power supply
Circuit breaker
control relays
Emergency backup
battery switching
Battery Backup
• 4 12V Lead acid batteries
– Series connected to provide 48V
– Capacity 7Ahrs
• Charged by a 1A, 48 V battery charger
– Powered by the incoming mains.
• LEDs used to indicate:
– Batteries charged
– Mains connected
Recent Problems
• System is at least 27 years old
• Concern that the electronic components are
approaching end of life
– sticking relay
– capacitor failure in the magnet PSU which is of a
similar age
• ECS Group at DL asked to provide a
Replacement QD system.
Replacement (DL) System
• Follow original principles of PSI design
• Update components
• Use a modular design
• Single PCB per quench channel
• At least existing system user interface
Quench detection cards
• Modular Design
• Updated components
– Isolation amplifier
– Relay
– Latching circuit
• Isolation of voltage taps
• Test points on each card
Power supply
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2x 230Vac to 48Vdc PSUs
2x 48Vdc to ±15Vdc PSUs
2x 48Vdc to 12Vdc PSUs
Control Relays
Battery Backup
• The battery back-up crate will follow the
existing design closely.
• A 48V, 1A charger will be used to charge
four 12V batteries in series.
• The batteries will be 7 Ahr units.
Upgrades
• Variable voltage limits on quench detection
– Voltage range from 10mV to 110mV
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A relay off indicator LED on each card
A reset button on each card
Test points are provided on each card
Greater level of output diagnostics
– Tripped channel can now be identified
– Status indicators of each power supply
• Increased EMC protection to prevent nuisance
trips
Progress
• Quench Detection Cards tested
• Power supply and battery backup still to
be completed
• Final testing of the complete system to be
carried out before the end of July
• Test of system with AFC in R9 at the end
of July
Questions?