500kW regenerating dc drive

[Drivesrock]

Hi all.
I have a customer that wants to upgrade his old dc drives. A new drive solution I have. The application is a downhill conveyor where the motors constantly regenerate and the existing drives have high speed dc circuit breakers with trip circuits connected to shunts in the dc circuits.
In the event of a mains failure and the thyristors are conducting the trip circuit operates the HSCB to protect the thyristors. It has apparently worked very well for many years. DC Fuses are not an option as the mains blackouts/brownouts are frequent.
What I am looking for is a standard trip circuit to replace the existing for which there are no more spares and no circuit diagrams. Any suggestions please?

Thanks in advance.

 

[ScottyUK]

Brush Electrical Machines have a subassembly called the Over Current Protection Unit or OCPU which basically performs this function for the field of a generator; it's part of their MAVR voltage regulator. They would probably sell you one. Knowing Brush it will be pricey, but possibly less than replacing the drive system. Note I said 'possibly'!


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