NASA Technical Reports Server (NTRS) 19940024210: Breakdown testing of wiring insulation

8 Pages·0.1 MB·English

by  NASA Technical Reports Server (NTRS)

BREAKDOWN TESTING OF WIRING INSULATION
N94-28713
J.R. Laghari
State University of New York at Buffalo
Buffalo, New York
BACKGROUND
M81381 (Polyimide)is widely used for wiring
insulation in aerospace applications
Advantages
• Light Weight
• High Service Temperature
• High Breakdown Strength
• Availability
Disadvantages
• Resistive Heating'
• Lossy at High Temperature
• Absorbs Moisture
• Arc Tracking
• Fire Hazard
TYPICAL OPERATING VOLTAGES
. 28 Voltsdc (Space Shuttle)
• 120 Volts dc
(CurrentlyProposedfor SpaceStationFreedom)
• 28-270 Volts dc
(ExpendableLaunchVehicles)
• 115 V 3-ph400 Hz (AerospaceApplications)
165
TASK
To evaluate dielectric strength at high
temperature of potential wiring insulation
recommended by NASA LeRC to replace
existing M81381 (Polyimide)
Top Candidates Recommended by NASA
LeRC for Dielectric Testing at UB
Gore 12 AWG
Gore 20 AWG
Tensolite 12 AWG
Tensolite 20 AWG
Filotex 12 AWG
Filotex 20 AWG
Kapton (M81381) 12 AWG
Kapton (M81381) 20 AWG
Teledyne 12 AWG
Teledyne 20 AWG
Barcel 20 AWG
Champlain 20 AWG
166
Wiring Cable Specifications
Sample InsulationSystem Insulation
Thickness
Gore-12 PTFE/High StrengthPTFE/PTFE 6 mil
Gore-20 PTFE/High StrengthPTFE./PTFE 6 rail
Tensolite-12 PTFE/Polyimide/PTFE 7.15 rail
Tensolite-20 PTFE/Polyimide/PTFE 6.15 rail
Filotex-12 PTFE/Polyimide/FEP 6.9 rail
Filotex-20 PTFE/Polyimide/FEP 6.5 mi]
M81381-12 KaptonwithPolyimidetopcoat 8.6rail
M81381-20 KaptonwithPolyimidetopcoat 8.6rail
Teledyne-12 PTFE/Polyimide/PTFE - 6 mil
Teledyne.20 PTFF_/Polyimide/PTFE - 6 rail
Barcel-20 Kapton/UnsinterePdTFE, Buttrap - 6 rail
Champlain-20 Kapton/ ExtrudedXL ETFE 5.7 mil
TEST FACILITY at UB
HighVoltage
TerminalSphere
Heater& Blower
-_,,_/ r-_
Ground
Elect_e
I II
HighTemperature GroundFeed-thin
CeramicBushing Wiring
Sample DigitalThermometer
167
20"
Gore-12
>
-%
0
C_
_._
0
>
10. "_
-1
0
0
s'o 1_o __o 26o 250
Temperature C
[] ac60Hz(0-P) • ac400Hz(0-P) • dc
2o
A IGore-20
>
Jl¢
,_,
0
>
10- r_
[] C3
0
en
0
0 5'o ,6o 15o _o 2so
Temperature C
ac 60 Hz (0-P) • ac 400 Hz(0-P) • dc
168
40,
Tensolite-121
>
" 30-
(3)
o
>
c 20-
[]
o • • •
to-
rn
Oi _'o 16o Iso 260
250
Temperature C
ac 60 Hz (O-P) • ac 400 Hz(O-P) • dc
40
Tensolite-20 J
>
--_ 30"
(13
4=,
0
>
c 20-
o
13
{0
rrt
s'o 160 I_o 260
250
Temperature C
[] ac60 Hz (O-P) • ac400 Hz(O-P) • dc
169
4O
IFilotex-12
>
30-
(D
0")
o_
.,,..
t-- 20"
0
t0
10"
0 s'o 16o 1_o 260 2so
0
Temperature C
= ac 60 Hz (O-P) • ac 400 Hz(O-P) • dc
40-
Filotex-20i
>
30-
.,,..,
¢= 20-
0
10
[] E_ o
10-
I:D
oi
_o ,6o 1_o _o 2so
0
Temperature C
o ac60Hz(O-P) • ac400Hz(O-P) • dc I
170
20-
ac60 Hz
>
x
x
x
C_
o 10- z
> _r
t..-
-4-
,4-
o l!
"o
0
0 so 160 15o 200 25O
Temperature C
• Gore-20
I r•7 GTeonres-o1li2te-20 z Filotex-12 x+ TFeilontseoxl-i2te0-12 J
20'
ac 400 Hz
>
x
C_
m x
o 10-
>
c
o z z
"o
m
o
s'o 16o I_o 26o
o 250
Temperature C
x Tensolite-12
I •[] TGeonrseo-1lit2e-20 •z GFiolorete-2x0-12 ÷ Filotex-20
171
40.
®
X
X
> _K
_" 30-
eo-, X z X
>
c 20-
0
+
[] ÷
o
10-
rn
0
0 5'0 160 1,50 200 25O
Temperature C
n Gore-12 • Gore-20 × Tensolite-12
• Tensolite-20 z Filotex-12 + Filotex-20
FUTURE WORK
Q Obtain breakdown strength of other constructions.
• Insulation resistance as a function of temperature.
• Multistress aging
(Electrical, Thermal and Radiation
CONCLUSION
• No dependence of breakdown strength on temperature for
constructions tested.
• Little effect of frequency on the breakdown characteristics.
172