8. TYPICAL VELOCITY FACTORS
These values of velocity factor are typical and may be used in the
absence of known values of cables.
These values may need changing after verifying on a specific cable.
Five output impedances are available (25, 50, 75, 100, 140 ohms) and
an auto impedance matching feature. The velocity factor can be set
between 0.2 and 0.99 to meet any cable test requirements.
Material
Cross section
mm
2
V.F
m/μS
m/uS
XLPE
35
0.52
156
78
XLPE
50
0.52
156
78
XLPE
70
0.53
160
80
XLPE
95
0.53
160
80
XLPE
185
0.55
165
81.5
XLPE
240
0.56
168
82
XLPE
300
0.56
170
82
XLPE
500
0.56
173
82.5
XLPE
630
0.57
173
82.5
PILC
70
0.52
156
78
PILC
185
0.52
156
78.5
PILC
240
0.53
156
79
PILC
300
0.55
165
80
PILC
0.1 in
2
0.52
156
78
PILC
0.3 in
2
0.52
156
78.5
PILC
0.4 in
2
0.53
156
79
PILC
0.5 in
2
0.55
165
80
Megger Instruments Limited, Archcliffe Road, Dover, Kent, CT17 9EN, England
T +44 (0)1 304 502101 F +44 (0)1 304 207342
Part No. 1005-021
Megger is a registered trademark
TDR2050_QS_EN_V01
Printed in England www.megger.com
This instrument is manufactured in the United Kingdom. The company reserves the right to change the specification or design without prior notice.
