Joslyn Clark DC contactors comprise three series for direct-current circuits.
5DP series (for defined applications) - contactors for variable-speed DC drives with thyristor (SCR) control, with normally open and normally closed power contacts (NO - normally open, NC - normally closed), an integrated normally closed (NC) dynamic-braking contact and magnetic blowouts that extinguish the DC arc and ensure circuit interruption (up to 200% under fault conditions); double-break Ag-CdO contacts - silver cadmium oxide - potted enclosure and coil; range 30–700 A, max. 500 V DC.
7400 series - electromagnetically operated contactors (sizes 1–5) used as main, reversing or accelerating contactors in DC motor starters and controllers, and for switching heating and battery loads; double-break Ag-CdO contacts with magnetic blowouts, up to four auxiliary contact blocks, AC or DC coils; range 25–300 A, max. 250 V DC.
7001 series - 40 A general-purpose DC contactor for variable-speed drives (SCR thyristor control, NO + NC contacts, magnetic blowouts, NC dynamic-braking contact); CSA and UL component approvals.
Railway applications: traction-drive, reversing and dynamic-braking circuits in industrial and mining locomotives and plant vehicles - up to 500 V DC. Outside the scope of 3 kV DC main traction circuits. No EN 61373 / EN 45545-2 qualification - use in rolling stock authorized for operation in the EU only after manufacturer confirmation.
