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VLD Voltage Limiting Devices

Voltage Limiting Devices
• Electrical isolation of insulated track sections and earthed
parts of installations
• Safe equipotential bonding in case of a short-circuit or earth
fault at the overhead contact line due to high-current-resistant
welding of the electrodes
• Discharge of lightning surges without short-circuit formation
due to lightning-resistant SDS ... voltage limiting device
• Short-circuit withstand capability
up to 25 kArms / 100 ms; 36 kArms / 75 ms
VLD Voltage Limiting Devices

EN 50122-1 describes the use of voltage limiting devices for d.c. and a.c. The SDS voltage limiting device consists of a spark gap unit and the re-
traction systems for so-called „open traction system earthing“ of conduc- spective connecting kit and can be directly connected to the rail or over-
tive components of the overhead contact line and pantograph zone. head contact line tower.
Voltage limiting devices (SDS ...) are used to prevent the occurrence of
hazardous surges between the insulated tracks or track sections of electric The spark gap unit of type SDS 1 (Part No. 923 110) developed by DEHN
railways and earthed parts of the installation. has also been approved by the German Federal Railway Authority (EBA).
Their function is to permanently connect parts of the installation in the
overhead contact line and pantograph zone to the return circuit as soon
as the threshold voltage is exceeded.
In case of atmospheric overvoltages, the lightning-resistant SDS ... voltage
limiting device is capable of returning to its initial state after discharging
the impulse current. Only if the specified lightning current load is exceed-
ed, a permanent short-circuit is initiated by high-current-resistant welding
of the electrodes and the fuse link has to be replaced.

SDS 1 Voltage limiting device for a power-frequency sparkover voltage ≤ 940 V. 923 110 SDS 1
Type SDS ... 1
923 110 4013364092426 05 03 01 01 40 g
48,50 €
Part No. 923 110
VLD type (EN 50122-1) VLD-F
Power frequency sparkover voltage (Uaw) ≤ 940 V
d.c. sparkover voltage (Uag) 600 V +/- 20 %
Impulse sparkover voltage ≤ 1400 V (1kV/µs)
Self-extinguishing capability 300 A / 65 V
Lightning current discharge capacity (10/350 µs) 0.1x / 0.5x / 1x 5 kA
Lightning current withstand capability (10/350 µs) 25 kA
Safe short-circuit due to welding of the electrodes in case of alternating currents ≥ 2.5 kA / 1000 V / 30 ms, ≥ 1.5 kA / 1000 V / 100 ms
Safe short-circuit due to welding of the electrodes in case of direct currents ≥ 750 A / 250 ms
Short-circuit withstand capability 25 kArms / 100 ms; 36 kArms / 75 ms
Long-term current 1 kArms for t ≤ 120 s
Leakage current (Ilc) < 1 µA for 100 V d.c.
Operating temperature range (TU) -40 °C ... +80 °C
To be mounted with mast adapter MA SDS M12 or SIEMENS No. 8WL6503-xx
Approvals EBA
DB drawing No. 4 Ebs 15.13.20 Sheet 2

SDS 2 Voltage limiting device for a d.c. sparkover voltage of 350 V. 923 117 SDS 2
Type SDS ... 2
923 117 4013364093478 05 03 01 01 42 g
60,00 €
Part No. 923 117
VLD type (EN 50122-1) VLD-F
d.c. sparkover voltage (Uag) 350 V +/- 20 %
Impulse sparkover voltage ≤ 900 V (1 kV/µs)
Lightning current discharge capacity (10/350 µs) 0.1x / 0.5x / 1x 2 kA
Lightning current withstand capability (10/350 µs) 25 kA
Safe short-circuit due to welding of the electrodes in case of direct currents ≥ 600 A / 250 ms
Short-circuit withstand capability 25 kArms / 100 ms; 36 kArms / 75 ms
Long-term current 1 kArms for t ≤ 120 s
Leakage current (Ilc) < 1 µA for 100 V d.c.
Operating temperature range (TU) -40 °C ... +80 °C
To be mounted with mast adapter MA SDS M12 or SIEMENS No. 8WL6503-xx
Valid as of January 1, 2019 You will find detailed product information on our website 149