Product Description:

The E4809-747-005-E circuit card is produced by Okuma and belongs to the E4809 CNC Boards series. It is supplied as a firing interface that triggers the power semiconductors in a PPS-60C regenerative drive section. Inside a machine-tool cabinet, the board links the numerical controller to the thyristor stack, converting low-level commands into gate pulses for motor power. It enables precise speed and torque control in industrial automation applications.

Its board function is Firing Card, meaning it provides phase-aligned gate signals rather than analog voltage for power devices. The control topology is Thyristor Control, so the card times each silicon-controlled rectifier conduction period instead of modulating a transistor array. It is matched to the PPS-60C drive model, ensuring pulse timing and connector pinout coincide with that chassis. When installed in an LDU-600 power rack, it must handle armature currents up to 50 A while coordinating an output rating of 1.5 kW. The same rack expects an incoming line of 200-220 V three-phase at 50/60 Hz; the board samples those phases to determine correct firing angles. Pulse phase shifting is the method used, advancing or retarding the trigger instant to raise or lower motor voltage.

The card was designed for a DC Motor platform, so it bases its control loop on true armature current and a back-EMF signal. A D6 Absolute Encoder supplies precise position data to the CNC, while a Tachometer feeds instantaneous speed back to the firing logic; together they let the board correct load disturbances without overshoot. Because the pulse phase algorithm operates independently for each of the three supply phases, the assembly sustains constant torque across either 50 Hz or 60 Hz grids. Integration with the three-phase LDU-600 host keeps cable runs short and ensures noise immunity between feedback channels and the SCR gate circuitry.