DC Power Systems Protection
Most signal lines are powered by DC power sources. Raycap's DC power systems protection family consists of modular and compact SPD solutions developed to prevent supply interruptions. With RayDat SPLH-2-7A, RayDat PSC-2, and ProTec DMDR 20 models, it protects both grounded and floating lines; it carries high load currents up to 7 A and ensures trouble-free operation even in environments with severe mains disturbances.
Protecting the signal line in a measurement or communication system is not enough on its own — the DC power supply feeding that system is equally at risk. An impulse from the supply side will shut down the entire system, even if signal protection is intact. Raycap's DC power systems family is developed precisely for the protection of these supply lines.
The family offers three different approaches:
RayDat SPLH-2 Series — designed for the protection of ungrounded/floating DC power supplies. Coarse protection is provided by a two-pole gas discharge tube (GDT), and fine protection by a fast silicon (SAD) stage. Coordination between the two stages prevents voltage or impulse current "blind spots." The SPLH-2-7A model carries a 7 A load current (at 45 °C) — the highest current capacity in the family. It includes an internal EMI filter and 22 µH series inductance.
RayDat PSC-2 Series — designed for the protection of power supplies. Coarse protection is provided by a varistor (MOV), and fine protection by a fast silicon (SAD/TVS diode) stage. A distinguishing feature of the series is its very low residual voltage: < 32 V for the 12 V model, < 60 V for the 24 V model, and < 135 V for the 48 V model. Internal thermal disconnectors reduce the risk of thermal runaway in fault conditions or mains incursion into the low-voltage data circuit. Connection lines remain active when the module is removed from the base — protection replacement does not interrupt the supply.
ProTec DMDR 20 Series — designed according to the specific requirements of DC power systems in telecom power and railway applications. With a high-energy MOV + GDT hybrid structure, it provides both common mode and differential mode protection; a high nominal discharge current means extended service life under DC conditions. It features a remote contact + LED status indicator. 24, 48, 60, and 120 V (AC/DC) versions are available.
All models are 35 mm DIN rail mounted, equipped with screw terminals, and operate in the -40 °C … +80/85 °C range. The housings are UL 94 V-0 flame-retardant thermoplastic, with protection class IP 20. Standards: IEC/EN 61643-21, IEC 61643-11, UL 497B 4th Ed., UL 1449 5th Ed.
Common Features
- Very high surge withstand values
- Protection of both floating and grounded lines
- High load current up to 7 A
- Easy connection with screw terminals
- Multi-stage hybrid protection: coarse (GDT/MOV) + fine (SAD) stage
- Energy coordination between stages — no blind spots
- Internal thermal disconnector — thermal runaway protection
- Connection lines remain active during module replacement
- 35 mm DIN rail mounting (EN 60715)
- Protection class: IP 20 (embedded)
- Housing: UL 94 V-0 flame-retardant thermoplastic
- Operating temperature: -40 °C … +80/85 °C
RayDat SPLH-2-7A (compact, single-pole — UL Listed)
| SPLH-2-7A | |
|---|---|
| Nominal operating voltage (DC) U | 36 V |
| Max. continuous operating voltage U | 45 V |
| Nominal load current IL (45 °C) | 7 A |
| Nominal load current IL (80 °C) | 5 A |
| In (8/20 µs) line-to-ground | 10 kA |
| Total In (8/20 µs) | 20 kA |
| Iimp (10/350 µs) line-to-ground | 2.5 kA |
| Total Iimp (10/350 µs) | 5 kA |
| Protection level Up (line-to-ground) | < 1000 V |
| Protection level Up (line-to-line) | < 180 V |
| Response time t | < 1 ns |
| Insulation resistance R | > 45 MΩ |
| Series resistance per path R | < 1 Ω |
| Series inductance L | 22 µH |
| Transverse capacitance (line-to-ground / line-to-line) | < 2 nF / < 100 pF |
| Category | D1 / C1 / C2 / C3 |
| Conductor cross-section | 2.5 mm² |
| Dimensions / Weight | DIN 43880 2 TE / 90 g |
| Order code | 127 626 |
RayDat PSC-2 Series (low residual voltage, modular)
| 12 | 24 | 48 | |
|---|---|---|---|
| Protected line | 1 pair (2 conductors) | 1 pair | 1 pair |
| Nominal operating voltage U | 12 V | 24 V | 48 V |
| Max. continuous operating voltage U | 15 V | 28 V | 52 V |
| Nominal operating current IL (25 °C) | 4 A | 4 A | 4 A |
| In (8/20 µs) | 10 kA | 10 kA | 10 kA |
| Imax (8/20 µs) | 20 kA | 20 kA | 20 kA |
| Residual voltage @5 kA Ures | < 32 V | < 60 V | < 135 V |
| Response time tA | < 1 ns | < 1 ns | < 1 ns |
| Insulation resistance R | ≥ 15 MΩ | ≥ 28 MΩ | ≥ 52 MΩ |
| Series inductance per path L | 10–14 µH | 10–14 µH | 10–14 µH |
| Transverse capacitance C | < 5 nF | < 3 nF | < 1.5 nF |
| Category | C1 / C2 / C3 | ||
| Conductor cross-section (max.) | 4 mm² | ||
| Dimensions / Weight | DIN 43880 2/3 TE (12 mm) / 64 g | ||
| Order code | 7086.83 | 7086.84 | 7086.85 |
| Replacement module | 7086.86 | 7086.87 | 7086.88 |
ProTec DMDR 20 Series (telecom & railway — UL Recognized)
| 24* | 48 | 60 | 120 | |
|---|---|---|---|---|
| Nominal AC/DC voltage U | 17 V / 17 V | 34 V / 48 V | 43 V / 60 V | 85 V / 120 V |
| Max. continuous operating voltage (AC/DC) Uc | 24 V / 34 V | 48 V / 60 V | 60 V / 75 V | 120 V / 150 V |
| Uoc (1.2/50 µs) | 2.4 kV | 2.4 kV | 6 kV | 6 kV |
| Icw (8/20 µs) | 1.2 kA | 1.2 kA | 3 kA | 3 kA |
| Imax (8/20 µs) | 2 kA | 2 kA | 4 kA | 4 kA |
| Protection level Up (L-N) | < 250 V | < 500 V | < 600 V | < 1100 V |
| Protection level Up (L-PE / N-PE) | < 700 V | < 800 V | < 850 V | < 1200 V |
| Response time tA (L-N / L-PE) | < 25 ns / < 100 ns | |||
| TOV withstand 5 s (AC) U | 115 V | 148 V | 163 V | 225 V |
| Short-circuit withstand ISCCR (AC) | 2 kA | |||
| Protection element | High-energy MOV + GDT | |||
| Status indicator | Remote contact + green LED | |||
| Class | Class III / Type 3 / Type 4CA | |||
| Dimensions / Weight | DIN 43880 1 TE (18 mm) / 96 g |
The DC power systems protection family is used for protecting DC lines that power signal and control systems:
- DC power supplies feeding signal lines — prevention of supply interruptions
- Floating DC supply systems — SPLH-2 series
- Grounded DC supply systems — PSC-2 and DMDR series
- Telecommunication power systems — 48 V DC supply (ProTec DMDR)
- Railway applications — Signaling and control supplies (ProTec DMDR)
- Instrumentation power supplies — 12 V / 24 V / 48 V DC supplies
- PLC and control panel supplies — 24 V DC control voltage
- Lines requiring high current — up to 7 A (SPLH-2-7A)
- Sensitive electronic supply — points requiring low residual voltage (PSC-2)
- Facilities with mains incursion risk — mains incursion protection with thermal disconnector
- Environments with severe mains disturbances — assurance of continuous operation
- Remotely monitored facilities — DMDR with remote contact + LED indicator
- Systems requiring uninterrupted operation — lines remain active during module replacement
