Product Details:

The RELIANCE 0-49009-3 transductor board is an essential drive spare part designed for legacy RELIANCE CardPak DC drive rack control systems. This current sensing card uses magnetic transductor components to sample AC current signals from the thyristor power stack, converting high-power primary current into isolated low-level analog feedback signals for the main regulator card. The regulator relies on this precise feedback signal to implement current closed-loop regulation, torque limit calculation and fast overcurrent protection. It forms the critical current feedback loop that supports stable torque control of the CardPak drive. If the transductor core suffers saturation, signal drift or circuit failure, the drive will show incorrect current readings, unstable torque output, false overcurrent alarms and sudden protective shutdown.

This current sensing card adopts standard plug-in slot structure and can be directly inserted into the dedicated RELIANCE CardPak drive chassis. It communicates with regulator cards, limit circuit boards, ramp timing boards and auxiliary power boards through the internal backplane bus. The magnetic transductor design provides high galvanic isolation between the high-voltage power circuit and low-voltage control circuit, effectively blocking surge voltage and common-mode interference transmitted from the power section. An on-board adjustment potentiometer is reserved for technicians to calibrate signal gain and offset to match the rated current of different power stacks. Multiple low-pass filter circuits suppress commutation noise generated during thyristor switching, stabilizing analog feedback output in harsh industrial electromagnetic environments. The board is powered by 24V DC auxiliary control power supply, with a net weight around 0.52kg. Its rated working ambient temperature range is 0℃ to 55℃, and storage temperature ranges from -20℃ to 70℃. LED status indicators display signal output state for maintenance technicians to quickly judge whether the current feedback loop works normally.

This RELIANCE 0-49009-3 current sensing card is widely stocked as maintenance spare parts for traditional DC speed regulation equipment in metallurgy rolling production lines, paper making machines, cable extrusion lines and other heavy-duty industrial equipment requiring precise closed-loop current and torque control. The original manufacturer has discontinued this transductor board, and most units available on the global industrial spare parts market are fully tested refurbished units. Before installation, technicians need to inspect magnetic transductor cores, precision resistors, filter capacitors, PCB traces, solder joints and gold fingers for aging, insulation damage or poor contact. After rack installation, primary wiring polarity must be confirmed, current feedback calibration should be completed, and no-load and load current consistency tests need to be carried out. Careful inspection and calibration of this transductor board can effectively avoid torque oscillation and false overcurrent trips, reducing unplanned production downtime.