Onboard fuse boxes for installation on vehicles, rated 750 V DC, 1500 V DC and 2000 V DC. One box accommodates 1, 2 or 3 independent circuits with common or separate inputs and outputs; with six fuse-links in parallel, current can reach 3500 A DC per box. Current ranges: 750 V DC bogie version 250–1400 A, 1500 V DC roof version 400–3500 A, 2000 V DC auxiliary-circuit version 160–560 A (two fuse-links in parallel). Breaking capacity depends on the characteristic of the installed DC fuse-link. IP55 protection, horizontal or vertical mounting, operating temperature −20 °C to +40 °C.
The enclosure and cover form a one-piece moulding of 25% glass-fibre-reinforced polyester (class M1F1 according to NF F 16 101/16 102), coated with 300–400 µm gelcoat (class M1F3) or made from through-coloured SMC (class M1F2). Dimensions and the number and position of cable entries are adapted to the project; the cover uses captive screws. Installation on U-rails through Micaver insulators or directly on moulded-in threaded inserts. Resistant to mechanical impact, rain, snow, UV radiation, detergents and vibration - tested according to IEC 61373 level 3.
Options: microswitches for fuse-operation signalling, inspection window in the cover, Mors Smitt HVDR*) voltage-presence relay, voltage/current/energy measurement. Standard colour RAL 7010, other RAL colours from 200 units. Fuse-links to IEC or UL standard. Mersen supplies LCC, RAMS and FMEA analyses and performs type tests. Datasheets are available for all three versions: bogie 750 V DC, roof 1500 V DC and 2000 V DC.
*) Mors Smitt HVDR - DC traction-line voltage detection relay manufactured by Mors Smitt, installed in the box on the fuse output side. It connects directly to the high-voltage circuit: voltage is measured through an internal resistive divider (hundreds of kΩ) and no auxiliary supply is required. When voltage exceeds the pickup threshold, the relay switches auxiliary contacts (1 NO + 1 NC) for vehicle control circuits - indicating that the circuit downstream of the fuse is energized or that the fuse-link is intact. Mors Smitt 750 V DC and 1500 V DC versions declare compliance with EN 60077 and EN 61373. Pickup and dropout thresholds are specified in the relay datasheet for the relevant network voltage.
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