• Global Certificate: ISO 9001 : 2015

Differential relays

DC or AC current differential protection, AC or DC voltage differential protection, etc.

Applications and operation

These relays are used in applications such as DC or AC current differential protection, AC or DC voltage differential protection, etc.

For current applications, two sets of bars or two large windings are opposed around a magnetic circuit.
For voltage applications, there are 2 concentric coils that are opposed around a magnetic circuit.

Depending on the intensities passing through the differential relay, it can be either overmoulded by a technical epoxy resin of railway quality, or directly mounted in a standardized case of our range (Type MK120-160-200).

Reference FT 50586
Reference FT 52249
Differential ground fault detection relay

In on-board applications, direct ground access is unavailable, which is why a differential current relay is used to detect leaks by comparing the incoming and outgoing electric traction circuit lines or the current imbalance in the braking system. It is mounted between the main rectifier and the inverter and also between the rectifier and the auxiliary inverter. It is installed on metros, trams and diesel locomotives.

SEE DATASHEET FT52471
Differential ground fault detection relay, high power

In on-board applications, direct ground access is unavailable, which is why a differential current relay is used to detect leaks by comparing incoming and outgoing electric traction circuit lines. As example, this relay is mounted on BB26000 locomotives. In addition, an 11 kAdc overload current relay is mounted on the main busbar to trip the main circuit breaker to avoid overall overload in the locomotive.

SEE DATASHEET FT551172

Options available

Contacts 1 inverter or 1 N/O-1N/C
Agpd or Tungsten Metallurgy
Magnetic hooking at work
Test buttons and/or facade rearmament
Rearmament coil for remote handling
Smoke Fire test (EN45545)
Specific engraving on terminals
Available connectors:

  • Faston 5mm, Faston 6.3mm, single or double
  • Screw terminals for eyelet lug M4, M5, M6
  • Push-in type insulated connector
  • Other possible solutions on request

Current differential relays: Custom bars