The present running 3-phase Electrical Locomotives using the design of MICAS S2 class of Electronic PCB’s are of late 1980’s vintage. Many components have already been declared obsolete by the OEM’s years ago. Due to this, the genuisness of many parts which are currently being purchased is not very certain. The failures are likely to increase in future and maintenance could be a serious problem.
To overcome such difficulties we have undertaken re-design of MICAS S2 electronic PCB’s retaining the same functionality and straight-away interchangeable. In this connection we have already developed 10 types of PCB’s namely: 1. UF B701 A01 Bus Coupler Board 2. UF B660 A01 Bus Coupler Board 3. AR B705 B01 Signal Routing Board 4. UA B630 A91 Signal Conditioning Board 5. UA B630 A93 Signal Conditioning Board 6. UA B630 A36 Signal Conditioning Board 7. AF B635 B08 Fibre Optic Interface Board 8. UR B512 D15 Digital I/O Board 9. KU B921 A01 Power Supply Board 10. UA B514 B33 Analog I/O Board
Since the MICAS vehicle bus transfers the data by using two different media, one with the local bus and other with the remote bus, this bus coupler serves as an electrical isolator and level converter between the local bus and remote bus. They regenerate the signals received by the local bus or the remote bus and transmit them on the remote bus or the local bus. A data conversion does not take place. If there is a continuous signal transmitter, the corresponding transmission direction will be switched off. UF B701 A01 board has single channel Optic fibre Transmitter and receiver.
The new traction control electronics family realizes a new protection concept for electronics against electromagnetic interface. As a result, all the process signals are taken to the front panel of the individual electronic devices via screened cables and connectors. The signal routing board (AR B705) allows to connect up to 18 signals originating from the slightly emc populated peripheral range e.g. sensor signals via 6 sub-d connectors. These signals can be passed on to the rear edge connector. This card protects internal range against small disturbing pulses originating from the peripheral range by using simple RC filters.
The signal conditioning board is used to transfer signals between internal and external zones. Signals from peripheral zone are fed to the front panel via shielded cables by means of 9-pin sub-D connectors. They are processed and relayed to the rack connectors. The six measuring channels for the LEM-Transducers essentially consists of an input amplifier, which can function as current or voltage amplifier, a low pass filter and a comparator. Two channels are equipped with both rectifier and integrator. The six measuring channels can also be used to monitor the gate unit supply. Furthermore the board allows the testing of both LEM-transducer by means of its test winding and the measuring channels.
The Fibre optical Transmitter/Receiver board is a part of the control electronics for the drive control unit. The Fibre optical Transmitter/Receiver in (LWL) AF B635 B08 converts the electrical firing pulses received from AS and NS controllers into corresponding light pulses for potential free and interference free transfer to the gate units. The feedback signal also transferred optically is converted into electrical impulses. There are 8 channels each for transmitter and receiver. For transmitter, signal level for optical logic“0” is <40 dBm and optical logic “1” is >-20dBm. Similarly signal level for receiver optical logic“0” is <-40 dBm and optical logic “1” is between -24 dBm to -12dBm
KU B921 is a multiple Power Supply with 160W DC-DC- Converter with potential isolation. It generates the Output Voltages 5V/4A, ±15V/1.5A and ±24V/2A with an input range from 66 to 154 VDC. It operates from -55 to 100°C. Its efficiency is upto 90%.