Siemens C98043-A7002-L4-13 | SIMOREG DC-MASTER 6RA70 Power Interface Board — Thyristor Firing & Safety Monitoring
Part Number: C98043-A7002-L4-13
Alternate Reference: 6RY1703-0DA02
Manufacturer: Siemens AG (Germany)
Product Type: Power Interface Board (PIB) — Thyristor Firing, Safety Monitoring, Voltage Acquisition
Product Family: SIMOREG DC-MASTER 6RA70 Series
Overview
The C98043-A7002-L4-13 is the Power Interface Board (PIB) for the Siemens SIMOREG DC-MASTER 6RA70 series DC drive converters.
This board occupies a central position in the 6RA70's electronics box architecture, serving as the interface layer between the control unit (CUD1, part number C98043-A7001) and the drive's thyristor power section. Its core responsibilities span three critical functions: generating and distributing the thyristor firing pulses that control the armature converter output, performing safety monitoring of the power section, and acquiring the voltage and current measurement signals that feed the control electronics.
The SIMOREG DC-MASTER 6RA70 is Siemens' fully digital DC drive platform covering converter ratings from 6 kW to 2500 kW.
Introduced and continuously refined through the 1990s and 2000s, the 6RA70 series served as the backbone of DC motor drive installations across the most demanding industrial sectors — steel rolling mills, paper machines, extruder lines, hoisting and crane systems, test stands, winders and unwinders, and marine propulsion systems.
Many of these installations remain in productive service today, making the C98043-A7002-L4-13 one of the most actively sought DC drive spare parts in the industrial market.
The -13 suffix appended to the L4 base designates this specific production revision of the Power Interface Board.
Successive revisions within the L4 series incorporated component updates, layout refinements, and reliability improvements while maintaining full functional and mechanical compatibility with all earlier revisions in the same base (L4) series.
Key Specifications
| Parameter |
Value |
| Part Number |
C98043-A7002-L4-13 |
| Alternate Order No. |
6RY1703-0DA02 |
| Manufacturer |
Siemens AG |
| Product Type |
Power Interface Board (PIB) |
| Product Family |
SIMOREG DC-MASTER 6RA70 |
| Drive Power Range |
6 kW to 2500 kW |
| Core Functions |
Thyristor firing pulses, safety monitoring, voltage acquisition |
| Production Status |
Discontinued by Manufacturer |
| Country of Origin |
Germany / Romania |
Power Interface Board — Core Functions in 6RA70 Architecture
The SIMOREG DC-MASTER 6RA70 controls DC motor speed by varying the DC voltage and current applied to the motor's armature winding. This is done using a thyristor bridge — a bank of silicon-controlled rectifiers (SCRs) that convert the AC supply voltage into a controlled DC output.
The precise moment at which each thyristor in the bridge is triggered determines the output DC voltage: early triggering produces higher output, late triggering produces lower.
The C98043-A7002-L4-13 is the board that executes this triggering.
It receives the firing angle commands from the CUD1 control board, generates the corresponding firing pulses timed to the AC supply frequency, and distributes these pulses to the gate terminals of the individual thyristor modules in the power stack.
The accuracy and timing precision of this board's pulse generation directly determines how tightly the armature current and speed control loops can follow their setpoints.
The board also monitors the power section continuously. Zero-crossing detection of the AC supply synchronises the firing pulse timing.
Overvoltage and overcurrent monitoring in the power stage provides hardware-level protection that responds faster than the control software can.
Voltage acquisition from the armature circuit and the field supply is routed through the PIB back to the control board's measurement inputs.
L4 Series and the -13 Revision
The C98043-A7002 Power Interface Board has been produced across multiple revision levels designated by the L-suffix (L1, L2, L3, L4) and further sub-revisions within each L level (e.g., -8, -9, -11, -12, -13 within the L4 series). Each revision introduced incremental improvements.
Component substitutions for discontinued ICs, PCB layout changes for improved EMC, and reliability enhancements to specific circuit sections have all been addressed in successive revisions.
From a maintenance perspective, all revisions within the same L base (i.e., all L4 sub-revisions including -13) are interchangeable. Installing a -13 revision in a drive that originally had -8 or -11 does not require any parameter changes or reconfiguration.
The drive's parameters reside on the CUD1 board, not on the PIB.
6RA70 Drive Architecture Context
The SIMOREG 6RA70 electronics box contains several boards working together:
- CUD1 (C98043-A7001): Main microprocessor control board — the drive's brain
- PIB (C98043-A7002): Power interface board — firing pulses, safety monitoring
- Field Supply Board (C98043-A7004): Controls motor field current
- Optional CUD2 (C98043-A7006): Expanded I/O extension board
The C98043-A7002-L4-13 PIB communicates with the CUD1 through a dedicated ribbon cable connector. Disruption of this interface — through a failed connector, a damaged cable, or a faulty PIB — produces firing pulse faults on the drive display and stops the armature output immediately.
FAQ
Q1: The SIMOREG 6RA70 shows fault F001 (line supply fault) or F003 (armature overcurrent) immediately at switch-on, even with no load connected and confirmed AC supply. Could the C98043-A7002-L4-13 be the fault source?
Both F001 and F003 can originate from the PIB. F001 is triggered if the zero-crossing detection on the PIB cannot synchronise to the AC supply — a failure in the PIB's sync circuit causes the fault even with a healthy supply.
F003 at no load can result from a thyristor firing pulse fault (incorrect triggering angle or missing pulses) generated by the PIB.
Before replacing the board, verify the AC supply phase voltages at the drive terminals and check the PIB's ribbon cable connector to CUD1 for correct seating.
Q2: The C98043-A7002-L4-13 is discontinued. What are the most reliable sources for this board?
With the 6RA70 series in end-of-life status from Siemens, the specialist industrial DC drive aftermarket is the primary source. Reputable DC drive repair companies hold tested exchange boards with warranty.
When sourcing, confirm the board is the L4 sub-series (any -xx suffix within L4 is acceptable). Boards from the L1, L2, or L3 series are from different generations and may have different connector or circuit configurations — confirm compatibility before ordering if an L4 is unavailable.
Q3: After installing a replacement C98043-A7002-L4-13, should the drive be recommissioned?
Not for a like-for-like board replacement. The PIB does not hold drive parameters. The drive's configuration resides on the CUD1. After board replacement, power up normally and observe the drive's start-up sequence — the firing pulses should resume immediately.
Verify that the drive reaches its ready state and that current waveforms look normal under light load before returning to full production.
Q4: The drive shows intermittent F003 during heavy load transitions only. The motor and cabling have been confirmed healthy. Is the PIB likely the cause?
Intermittent overcurrent faults under load transitions can indicate a failing thyristor (which would show as consistently high current on one phase), or a PIB issue where one firing pulse channel is marginally weak — causing a thyristor to fail to turn on properly under certain load conditions.
Check whether the fault is associated with a specific phase by monitoring the armature current waveform on an oscilloscope.
An asymmetric or missing pulse on one phase points to the PIB. A saturating phase current on all three phases suggests a thyristor module fault.
Q5: Can the C98043-A7002-L4-13 from a 400V-rated 6RA70 drive be used in a replacement in a 460V-rated drive?
The PIB board serves the drive's electronics section and firing pulse generation — functions that are the same regardless of the drive's rated armature voltage (400V vs 460V).
The armature voltage rating of the drive is determined by the thyristor modules and the power section design, not by the PIB.
The same C98043-A7002-L4-13 board is used across the 6RA70 range regardless of armature voltage rating.
Confirm this against the drive's hardware documentation for your specific model if there is any uncertainty.
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