Hi-pot results summary

Speaker - Lab

MQXFA Electrical requirements and He BD

voltages

2

Component V_test

@ warm

V_test

@ 1.9 K

V_test

@ warm

after He

Coil-Ground 3680 V 1840 V 368 V

Coil-Heater 3680 V 2300 V 460 V

Failure 10 K 75 K 150 K 300 K

He Breakdown

Voltage (0.2 mm)

300 V 350 V 270 V 200 V

(2018-04-23)

MQXFA Electrical Design Criteria: EDMS 1963398 v4/ Docdb 879

Design 10 K 75 K 150 K 300 K

Polyimide BD

Voltage (50 mm)

10000 V 7000 K

He BD (4 mm) 11000 V 2500 V 1500 V 900 V

MQXF coils (Test after fabrication)

3

Coil to quench heater requirements: 3680 V

(since ~04/18)

55 coils have been tested after fabrication (220

heaters)

26 coils (* in the table) have been assembled into a

magnet (104 heaters)

#

coil

2000

V

2500

V

3000

V

3200

V

3680

V

3700

V

5000

V

Short

model

29 1 23

(17*)

3 1 1

MQXFA 18 2 (2*) 11 (7*) 5

MQXFB 8 4 4

No issues but test voltages changed over time

Coils assembled in a magnet

4

Magnets LONG

MIRROR

US-

HiLumi

MQXFS1

US-

HiLumi

MQXFS3

CERN

MQXFS4

CERN

MQXFS5

CERN

MQXFA

P1

US-

HiLumi

MQXFAP

2

US-

HiLumi

coils P1 103, 104,

3, 5

105, 106

107, 7, 8

108, 109

110, 111

203, 204

205, 206

P2, P3,

P4, P5

102, 104

105, 106

# of training 52 349 100 8 50 18 29

# of

thermocycle

s

? 8 5 3 3 3 1

5

MQXFS3 @CERN after cold test (May 2018)

Coil 105, 106, 107

5 thermal cycles

1 full disassembly

~100 quenches

105 106 107 8

OLL 9585 V 7325 V 10000 V 10000 V

OLH 5220 V 5694 V 10000 V 10000 V

ORH 5887 V (?) 5020 V 6747 V 1500-3000 V

ORL 6542 V 6324 V 7211 V 10000 V

First breakdown voltages testing up to 10000 V (200 V steps and 30 s waiting time)

1000 - 2000 V

0 - 500 V

2000 - 3680 V

> 3680 V

Coil 8

2 thermal

cycles

~50 quenches

Coil 8 ORH failed the hipot at the test facility

105 106 107 8

OLL 7589 V 5777 V 10000 V 10000 V

OLH 5354 V 5396 V 10000 V 10000 V

ORH 6869 V (?) 3570 V 136 V 859 V

ORL 6609 V 5097 V 144 V 10000 V

6

MQXFS3 Hi-pot historyMQXFS3a (105, 106, 107 and 7)QH passed Hipot in air up to 3000 V before cold test (test facility)

Nov 23 2016 (test facility) : failure going up to 3000 V in air after cold test. This test is done in

the test facility going up to 3000 V very fast. No recording of breakdown voltage. It was probably

a breakdown of the facility. (EDMS 2020286)

MQXFS3c: (105, 106, 107 coil 7 substituted with coil 8)

May 31st 2017 (bldg 927) coil 105, 106, 107, 7 and 8 passed the hipot tests up to 2500 V done

in air in bldg 927 (coil on the table). Confirmation that the failure in Nov 2016 was due to the test

facility

30th of April 2018 (test facility): first failure after cold test is observed in coil 8 going up very

fast to 3000 V. Second failure going up to 1000 V. No recording of the BD voltage. It passed at

500 V. Coil 8 OHR quench heater was identified as the source of problem

May 18th 2018 (test facility): Test in He gas was performed (results in slide 21)

June 20th 2018 (bldg 927) : hipot tests in air with coil on the table. 200 V steps and wait 30 s

each step. Coil 107 OHR QH failed at 6747 V (first failure) and coil 107 ORL QH failed at 7211 V

(first failure)

January 10th 2018 (Where?): hipot tests in air with coils on the table. High voltage test up 5000

Vat 1kV/min. ORH QH failed at 181 V going up to 1000 V and it was not tested up to 5000/10000

V. Burn test up to 10000 V (500 V test)

Coil 203, 204, 205, 206

3 thermal cycles

~50 quenches

7

MQXFS5 @CERN after cold test

Breakdown voltages testing up to 3700 V (Jan 2019)

1000 - 2000 V

0 - 500 V

2000 - 3680 V

> 3680 V

206

2000 V

2500 V

5000 V

10000 V

up to 10000 V

203 204 205 206

OLL 3700 V 3700 V 3700 V 3700 V

OLH 3700 V 3700 V 3700 V 2000 V

ORH 3700 V 3700 V 3700 V 3700 V

ORL 3700 V 3700 V 3700 V 3700 V

All quench heaters passed the hipot test up to 1000 V after the first cold test

106 OLH breakdown the first time at 2000 V going up to 2000 at flat top

Coil 108, 109, 110, 111

1 thermal cycles

~9 quenches

8

MQXFS4a @CERN after cold test

All passed breakdown voltages tests up to 1000 V in the test facility

1000 - 2000 V

0 - 500 V

2000 - 3680 V

> 3680 V

108 109 110 111

OLL 1020 V 1020 V 1020 V 1020 V

OLH 1020 V 1020 V 1020 V 1020 V

ORH 1020 V 1020 V 1020 V 1020 V

ORL 1020 V 1020 V 1020 V 1020 V

Short model MQXFS1e: magnet history

9

MQXFS1 - the first 150 mm aperture, 1.5 m long Nb3Sn quadrupole within

the CERN and LARP collaboration

Coils fabricated by CERN (#103 and #104) and LARP (#3 and #5)

Electrical checkout after fabrication: no issues up to 2500 V

Five tests performed since 2016

All QH passed the hipot test in air up to 1000 V after cold test

119 spontaneous quenches

230 provoked quenches and trips (I>1 kA)

Total of 8 thermal cycles (not counting the latest one for the hi-

potting tests).

10

Short model MQXFS1e: He gas Hi-pot tests

• CLIQ leads used for heater and coil connections• The CLIQ lead from the magnet connected to CL2

• OL heaters (8 strips) in coils 3 & 103 connected to CL3

• OL heaters (8 strips) in coils 5 & 104 connected to CL1

• Hi-pot tests at selected temperatures up to selected voltages (800, 1500 V)

Heater to coil

voltage CL1

Heater to coil Voltage

CL3

1.9 K 2300 V 2300 V

75 K 800 V (test 1)

1500 V

800 V (test 1)

1500 V

150 K 800 V (test 1)

1500 V

800 V (test 1)

1500 V (failed at flattop)

300 K 800 V (test 1)

1200 V

1360 V

800 V (test 1)

970 V

11

Short model MQXFS1e: 300 K in air (after He

gas tests)

The shorted heater (B01) was in the group that failed 150

K and 300 K hipot in He

Meet requirements at ambient T in air (after a thermocycle)

4 QH/coil: survivability of ~100% at 800V and ~94% at

1,500V at 150 K.

QH 3 (CL3) 103 (CL3) 5 (CL1) 104 (CL1)

OL1 460 V 460 V 460 V 460 V

OH2 short 460 V 460 V 460 V

OH3 460 V 460 V 460 V 460 V

OL4 460 V 460 V 460 V 460 V

12

Short model MQXFS1e: 300 K in air (after He

gas tests)

Heaters of coil 3 were further hi-potted in air up to 6000 V.

Ramp 1kV/min

QH 3 (CL3)

OL1 short

OH2 6000 V

OH3 6000 V

OL4 1840 V

MQXFAP1, MQXFAP2, LONG MIRROR

13

MQXFAP1

P2, P3, P4, P5 coil

18 Quenches

3 thermocycles

MQXFAP2

102, 104, 105, 106 coils

29 quenches

1 thermocycle

LONG MIRROR

P1 coil

22 training quenches

30 QH induced quenches

thermocycles

Electrical check out after coil fabrication: no issues but tested all < 3680

Coil autopsy after He: coil P01 (Mirror)

14

QH P01

OL1 3700 V

OH2 1500 V

OH3 2070 V

OL4 2340 V

500 - 2000 V

0 - 500 V

2000 - 3680 V

> 3680 V

OL1

OH2

OH3

OL4

RELE

First breakdown voltages testing up to 2500-3700 V

Some history of coil P01

15

QH P01

OL1 3700 V

OH2 1500 V 350 V 1100 V 750 V

OH3 2070 V 2200 V 2160 V 2040 V

OL4 2500 V 2500 V 2500 V 2340 V

Fabrication: 2500 V

shorted

after test in He: coil P5 (MQXFAP1)

16

QH P05

OL1 2380 V

OH2 shorted

OH3 2290 V

OL4 2820 V

First breakdown voltages testing up to 6000 V

1000 - 2000 V

0 - 1000 V

2000 - 3680 V

> 3680 V

OL1

OH2

OH3

OL4

QH to coil Hi-Pot before testing up to 3000 V

P5 First Failure after warmup 2380 V @ OL-LF 2.38kV

Short in heaters 1 and 2

0 2 4 6 8 10 12

1500

2000

2500

3000

3500

4000

4500

5000

5500

heater1

heater2

heater3

heater4

Hip

ot fa

ilure

vo

lta

ge

(V

)

Hipot voltage failure index

MQXFAP2 after He

17

First breakdown voltages testing up to 1500 V

6 out of 8 heater circuits passed the test

Heater circuit 3 failed at 1.4 kV (arc-fail,

116.5 μA leakage current)

Heater circuit 4 failed at 1.5 kV (arc-fail,

92.3 μA leakage current)

Each single heaters passed the Hi-pot test up to 460 V afterwards

Coil 108 short samples QH test after

fabrication

18

QH 108 long piece

OL1 6000 V

OH2 6000 V

OH3 6000 V

OL4 6000 V

108 coil: before He test passed hi-pot up to 6000 V

LQS03 model

19

Each heater covers half length, and full width of the surface

where it is applied

Each coil has four heaters:

2 OL heaters (one on return end, one on lead end)

2 IL heaters (one on return end, one on lead end)

Polyimide thickness: 25 µm

41 training quenches

4 trips

Thermocycles:

20

LQS03 hi-pot results after cold test

COIL 18 COIL 16 COIL 19 COIL 15

Lead end, OL 2.11 kV (BD) 2.47 kV (BD) 1.92 kV (A) 2.47 kV (BD)

Return end, OL 1.61 kV (A) 1.71 kV (A) 1.55 kV (A) 3.46 kV (A)

Lead end, IL 1.41 kV (A) 1.21 kV (A) 1.64 kV (A) 1.12 kV (A)

Return end, IL 1.31 kV (A) 1.61 kV (A) 1.42 kV (A) 1.47 kV (A)

Breakdown voltages testing up to 6000 V (OL), 2000 V (IL)

All heater passed the 650 V (max coil to heater voltage

seen by the magnet) Hipot test after breakdown test

500 - 2000 V

0 - 500 V

2000 - 3680 V

> 3680 V

21

First heater-coil hi-pot failure in air after

cold test

Hipot tests were

performed on #

104 heaters

Test were

performed up to

different max V

values

# 15 failures

between 1.2 and

3.0 kV.

# 11 failures

above 5.0 kV

No failure below

1200 V0 50 100 150 200 250 300 350

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

MQXFAP1 (coil P05)

MQXFAP2

MQXFS5

LONG MIRROR (coil P01)

MQXFS3 (coil 8)

MQXFS3 (coil 105 106 107)

MQXFS1

Co

il to

he

ate

r firs

t vo

lta

ge

fa

ilure

(V

)

# of quenches

He 150 K

He 300 K

Some comment on first failure plot

22

MQXFS1: 16 heaters, one QH in coil 3 failed in He at 150 K at 1500 V, one in

coil 5/104 circuit failed in He gas at 300 K at 1360 V. Coil 3 heaters were also

tested in air and a second QH failed and two passed (next slides).

MQXFS3a and b: coil 105 106 107 and 7. All heaters passed HV tests (very

fast) up to 1000 V. There was a failure going up to 3000 V. The instrument

does not register the breakdown failure value. All the QH passed the hipot in

air with coil on the table at 2500 V so the failure is due to the test facility issue.

MQXFS3c: coil 105 106 107 and 8. OHR heater of coil 8 passed the HV test

up to 1000 V after the first cold test. A second cold test took place and the

heater failed the HV tests (very fast) up to 3000 V afterwards. Then it failed the

test up to 1000 V and it passed at 500 V. I assumed the first failure between

1000 and 3000 V for coil 8 OHR.

Heaters passing heater to coil hi-pot in air

after cold test

23

Hipot tests were

performed on #

104 heaters

Test were

performed up to

different max V

values

# 78 heaters

passed the hi-pot

at > 1000 V

0 50 100 150 200 250 300 350

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

#4

#16

#2

#2#3

#1

#1

#12

#14

#12

MQXFAP1 (coil P2, P3,P4)

MQXFAP2

MQXFS5

LONG MIRROR (coil P01)

MQXFS3 (coil 8)

MQXFS3 (coil 105 106 107)

MQXFS3 (coil 7)

MQXFS4

MQXFS1

Ma

xim

um

hip

ot te

st vo

lta

ge

(V

)

# of quenches

#4 He 150 K

#7 He 300 K

Hipot test in He gas

24

Hipot tests were

performed on # 31

heaters

Not all the heaters

in MQXFS3 were

tested at each

temperature

All the tested

heaters passed

the 800 V hipot at

300K in He

50 100 150 200 250 300

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

#16

#11

#3

#2

#14

#15

#31

#16

MQXFS1 passed

MQXFS1 failed

MQXFS3 passed

# number of heaters that passed if >1

He

ate

r to

co

il vo

lta

ge

s (

V)

Temperature (K)

Some comments on Hipot test in He gas

25

MQXFS3: Hipot tests were made at 200 V steps waiting 30 s at each step.

Reported values are the ones observed before first failure. Failure of hipot

could be due to the test facility itself.

MQXFS1: Hipot tests were made at 1kV/min using CLIQ leads for heater and

coil connections

backup

26

27

MQXFS3 @CERN tests (Jan 2019)

Coil 105, 106, 107

5 thermal cycles

1 full disassembly

~100 quenches

105 106 107 8

OLL 3900 V * 5000 V 5000 V 5000 V

OLH 2300 V* 3600 V 5000 V 5000 V

ORH 3700 V* 4500 V* 181 V 659 V

ORL 2300 V* 3800 V* 5000 V 5000 V

Breakdown voltages testing up to 5000 V (* indicates not well insulated ext. wires)

1000 - 2000 V

0 - 500 V

2000 - 3680 V

> 3680 V

Coil 8

2 thermal

cycles

~50 quenches

OLL 10000 V 10000 V 10000 V 7000 V

OLH 10000 V 3600 V 10000 V 10000 V

ORH 6500 V 8500 V 181 V 659 V

ORL 10000 V 10000 V 8000 V 10000 V

Breakdown voltages testing up to 10000 V