HSCB Switch

[350yes]

Hello, I was wondering what the HSCB switch does on trains?

 

[aleggatta]

not familiar with the units, but High Speed Circuit Breakers are usually found on units that have DC current collection equipment. As such, without knowing the type of switch (momentary or latching) all I could comment is that it is a switch related to the High Speed Circuit Breaker, or a switch put in for the provision of a high speed circuit breaker.

 

[swt_passenger]

Same as previous reply, I think HSCB is the usual abbreviation for high speed circuit breaker, on modern EMU classes that’s usually the device that provides for remote controlled isolation of the DC shoe gear and DC equipment on the train. So the switch is probably controlling the breaker. Older DC units usually relied on a few big fuses.

 

[Bald Rick]

Anyone else thought, like me, that this would be a thread about moving your current account ?

 

[Fincra5]

Anyone else thought, like me, that this would be a thread about moving your current account ?

The amount I trip can call it HSBC when I'm teaching 700 Traction is embarrassing lol.

On a Class 700 is basically like a Big Surge Protector... If the voltage surges, the breakers open to protect the rest of the applicable equipment. Its in use on AC and DC. On AC the voltage comes into the HSCBs via the 4QC (at 800v DC) and in DC it comes straight from the Shoes.

 

[Stow]

Essentially does the same job as a shoe fuse

 

[Nym]

The amount I trip can call it HSBC when I'm teaching 700 Traction is embarrassing lol.

On a Class 700 is basically like a Big Surge Protector... If the voltage surges, the breakers open to protect the rest of the applicable equipment. Its in use on AC and DC. On AC the voltage comes into the HSCBs via the 4QC (at 800v DC) and in DC it comes straight from the Shoes.

Is one of the functions of the HSCB on more modern units.

The HSCB provides a means of isolation from the shoegear to the equipment, and like most MCCB (Moulded Case Circuit Breakers) has a number of programmable parameters for tripping.

Latest ABB catalogue I read when I was working on systems that used them, included I think 16 different trip type curves including;

• Undervoltage (too few volts)
• Overvoltage (too many volts)
• Overcurrent (too many amps, one means of failure for a fuse)
• Undercurrent (not usually used, but is there)
• dV/dt (How quickly voltage changes)
• dI/dt (How quickly current changes)
• i^2t (Analogous of BS88 and other 'standard' fuses, current-squared-time)
• UVR (Under-voltage release, from a remote circuit), then OVR. Used on rolling stock for isolation, coordination with VCBs etc etc etc.
• Remote shunts (where current detection is elsewhere).
• Many communications standards, MODBUS, CANBUS, PROFINET, PROFIBUS, RS422/485 and even Ethernet on some of the gucci ones.

I'll stop before this gets boring.

The reason for the switch (and usually a protecting MCB) is that these complex electronics are needing to be separately powered, unlike your MCBs at home (the simple ones) which operate only on the current flowing through them. RCDs and RCBOs do consume some current to function.

Trains don't usually use ABB units though (from my building services days), I've normally specified (forgive spelling here) Schaltbau, Seceron or other specialist ones for use there.