To prevent unintentional energization of both the forward and reverse coil at the same time, the coils are equipped with normally closed contacts, which are then wired in series with the opposite direction’s coil to act as an electrical interlock. Reversal of three-phase motor rotationīoth coils power contacts feed through a single set of OLR to provide running protection in both directions.

When the alternate coil is energized, Lines 1 and 3 are interchanged with Terminals 1 and 3, allowing for a phase shift in the 3-phase circuit, driving the motor and causing it to rotate in the opposite direction. They are connected so that under normal conditions, one coil will connect L1 with T1, L2 with T2, and 元 with T3. On-chip outputs short-circuit detection function.Motor Starters and Contactors 15 Forward/Reverse Starters NEMA Forward Reverse motor starter with OLRĪ forward/reverse magnetic motor starter is constructed from two regular contactors installed with a mechanical interlock that prevents both coils from pulling in simultaneously.12A peak startup output current and 12A peak brake output current.Allows forward, reverse, and brake operations in accordance with the external input signal.

External current detection resistor allows overcurrent detection and peak current control in the PWM operation mode.Both ICs required a large size heat sink to dissipate heat. To restart the operation, turn on 5V supply again. If the output pin is short-circuited directly to VCC or connected directly to GND, an output short circuit condition is detected and the output is latched in the off state. When the detector is activated, this pin is set low and all outputs are latched off. Monitor (Fault) pin is used when either of the outputs short-circuits detector, overcurrent detector, or overheat detector is activated.

The circuit requires 3 input signals: Enable for PWM input for speed control, IN1 and IN2 to change the motor direction and to apply the brake while the motor is in running condition. The circuit can drive brushed DC Motor with up to 12 A peak current. This high current forward-reverse DC motor driver is built using STK681-332 IC from ON Semiconductor.

Forward and reverse motor control