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MCBRDP1b*

test results CD1

Michal Duda, Franco J. Mangiarotti, Jerome Feuvrier, Guillaume Pichon

* Not P2 – comment from Ezio

WP3 meeting, 5-02-2020

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Magnet setup

This magnet is the second prototype of the two apertures D2 corrector MCBRD CCT:

Aperture V1 (red): tested in MCBRDP1 (old)

Aperture V2 (purple): series coil assembly (new)

Nominal current: 393 A

Ultimate current: 435 A

Temperature sensors: the coils formers are equipped with CCS temperature sensors

V1 inner – 332 (CCS11),

V1 outer – 333 (CCS12),

V2 outer – 342 (CCS21),

V2 inner – 343 (CCS22).

Instrumentation (will be swapped for CD2)

Aperture V1 (red) – magnetic measurement shaft

Aperture V2 (purple) – displacement sensor

CCS sensor

embedded

into Al former

Displacement sensor

in V2

Magnetic measurement

shaft in V1

Displacement

sensor

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Test stand: cluster D

2x 600 A power supply LHC type

Baseline protection: R_dump One aperture powering:

2x (vacuum switch + 1 ohm) (baseline)

Two apertures powering:

2x (vacuum switch + 1 ohm)

2x (mechanical switch + 0.7 ohm)

Quench detection: QDS: 4-6 ms @ 100 mV (baseline):

2.3 (EEx3-EEx5) – (EEx5-EEx8)

Potaim: 2 ms @ 100 mV

(EEx3-CL) – (CL-EEx8)

Test setup

Warm BP LHe BP LHe AP Warm AP

4160 V 2080 V 2080 V 416 V

New coils at cold: 2 * (I_nom * 2) + 500 = 2080 V (doubled at warm)

Old coils at warm (tested in He before): max 416 V

HV limits

Connection between coil, PC and switches to limit the PC max voltage to GND

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Test program

Temp Test type CD 1 CD 2

1.9 K

Low current splices + inductance 100 A ---

Protection studies (100, 200, 300 A) R_dump: 1.4, 2 ohm Metrosil (?)

Training 435 A 435 A

Holding ultimate 2(s), 4(b) h 2(s), 4 (b) h

Inductance 0 435 -435 0 2 A/s ---

Ramp rate to ultimate 6, 8, 10 A/s 6, 8, 10 A/s

Operational range powering -435 435 (square) -435 435 (square)

Magnetic measurements + splices Stair step (V1) Stair step + crosstalk (V2)

4.5 KTraining verification 435 A 435 A

Operational range powering -435 435 (square) -435 435 (square)

Test plan in EDMS: https://edms.cern.ch/document/2305749/2

finished

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HV test

Warm BP LHe BP LHe AP Warm AP

Spec4160 V

416 V (V1)2080 V 2080 V 416 V

Done2240 V

(both coils)*2150 V 2150 V 500 V

Done by Megger in 5 steps

At warm before powering when magnet was

attached to the insert short in V1 appeared

during the insulation test (between vtap

EE17 and EE18 to GND)

Short disappeared after the magnet move

and reopening wire box* Done before agreement on levels

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Cooldown and warmupVery well controlled processes:

• Cooldown max dT = 24 K

(between 300 and 80K)

• Warmup max dT = 20 K

CCS in V1 (red) a bit higher than

V2 (purple) possibly due to mm

shaft inside and lower He flow

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Powering to ultimate

Old coils (V1) showed very good memory – no

quench to the ultimate

New coils (V2) fast training with first quench

very close to the nominal

No quench when both powering (together and

square cycle) and during ramp rate studies

(max RR = 6 A/s because of PC limit)

MCBRDP1 training plot

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Quenches

Quenches only in new aperture V2

They all had a small precursor (very likely a resin cracking

between formers)

Two quenches started in EE25-CLV2 segment

One symmetrical quench detected by QDS

Q1: 387 A (a016) Q2: 416 A (S)(a017) Q3: 412 A (a022)

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Protection studies

Extraction at 300 A

Extraction at

100 A

Extraction at

200 A

Extraction at

300 A

Quench

at 416A

R_dump V1 V2 V1 V2 V1 V2 V2

QI [kA2s]1.4 3.16 nt 12.69 nt 18.98 nt nt

2 1.99 1.94 7.18 6.84 12.96 12.11 14.74

V_max

[V]

1.4 -126 nt -253 nt -379 nt nt

2 -190 -190 -377 -378 -565 -566 -785

MCBRDP1 protection studies

Baseline: R_dump = 2 ohm

Protection studies with

Metrosil foreseen in CD2

200 K

250 K

300 K

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Quench back

100A:

• 1.4 & 2 ohm: no QB

200A:

• 1.4 ohm: no QB

• 2 ohm: QB starts ~150 ms

300A:

• 1.4 ohm: QB starts ~100 ms

• 2 ohm: QB starts ~30 ms

Quench back effect not observed for 200 A and lower current

extraction for R_dump = 1.4 ohm, and 100 A for R_dump = 2 ohm

For smaller R_dump it starts later

For R_dump = 2 ohm in both, new and old coil quench back starts

almost at the same time

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Temperature of Al formersMax temperature of Al former after current

extraction in apertures

• V1: 300 A extraction T = 7.5 K

• V2: 300 A extraction T = 12.5 K

• V2: 416 A (quench) T = 22 K

Temperatures in both apertures after quench in V2

• V1 332 (inner): T = 2.2 K

• V1 333 (outer): T = 3.1 K

• V2 342 (outer): T = 22 K

• V2 343 (inner): T = 7.3 K

When quench in V2, V1 also sees temperature riseV1, V2: Different formers alloy?

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Inductance: only one AP powered

Inductance of AP2 MCBRDP1

• Inductance of the new coils is very

similar to the old one and a bit higher

than in MCBRDP1 AP2

• It starts decay at around 350 A

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Inductance: both AP powered

V1 V2

• Inductance is lower when other aperture is powered

• It decays earlier when both apertures are powered at the same time

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Conclusions

HV tests – all coils passed 2.2 kV BP in air, 2.1 kV in LHe and 500V at warm AP

Powering to ultimate - excellent coils memory of V1, very fast training of V2 (first quench just below the nominal)

Protection studies – baseline of R_dump of 2 ohm – faster quench back, lower quench integral, accepted voltage

Inductance shows exact the same tendency as for before tested magnets of this type

Additional temperature sensors embedded into the magnet former can be very useful for thermal studies of the magnet behavior during the powering

RRR and splices measurements were not very precise and will be repeated during CD2

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Next stepTemp Test type CD 1 CD 2

1.9 K

Low current splice + inductance 100 A ---

Protection studies (100, 200, 300 A) R_dump: 1.4, 2 ohm Metrosil (?)

Training 435 A 435 A

Holding ultimate 2(s), 4(b) h 2(s), 4 (b) h

Inductance 0 435 -435 0 2 A/s ---

Ramp rate to ultimate 6, 8, 10 A/s 6, 8, 10 A/s

Operational range powering -435 435 (square) -435 435 (square)

Magnetic measurements + splices Stair step (V1) Stair step + crosstalk (V2)

4.5 KTraining verification 435 A 435 A

Operational range powering -435 435 (square) -435 435 (square)

Starting later this week

Test plan in EDMS: https://edms.cern.ch/document/2305749/2

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S

cold poweringcooldown

max dT=30K

re-

instrumentationcold powering warmup

February

cooldown

max dT=30K

January

warm preparation warmup

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From Glyn

Fatigue test: 0 to ult at max A/s – 100/200 cycles, to see if the formers are worming up and adjust if needed

Electrical tests: the voltage to ground has been limited to 50% but for the final configuration I would like to test them. So at the end is it possible to connect to another power supply that can take the voltage and get the 435A with the 2 ohm EE unit to get the full 870 Volts. And the big metrosil.

Metrosils were sent yesterday, they should arrive end of the week