SRST185 Advanced Motion Controls Shunt Regulator

The Advanced Motion Controls SRST Series Shunt Regulator assemblies are designed to work with four quadrant regenerative servo drives. During braking most of the stored mechanical energy is fed back into the power supply, which charges the output capacitor to a higher voltage. If the charge reaches the drive's over-voltage shutdown point, motor control and braking will cease. To ensure smooth braking of large inertial loads the use of a shunt-regulator is recommended. Verify the need for a shunt regulator by operating the drive under the worst case braking condition. If the drive shuts off due to over-voltage (blinking red LED) a shunt regulator is necessary (typically during downward move or deceleration).

When the DC Bus reaches the shunt voltage of the shunt regulator assembly, the voltage comparator unit turns on the electronic switch, which connects the R1 power resistor across the DC Bus. This power resistor dissipates the energy from the DC Bus. After the bus voltage is reduced to less than the shunt voltage setting the resistor is disconnected from the bus. A small hysterisis loop allows time between switching. The SRST assemblies are manufactured with standard shunt voltages of 50, 70, 80, 90, 175, 185, 380, and 400 volts.

The SRST50, 70, 80, 90, 175, 185 are designed for use with servo drives up to 200 volts. These models have a 200 VDC, 1200 μF filter capacitor in them.

The SRST380 and SRST400 are designed for use with servo drives up to 400 volts. These models have a 450 VDC, 330 μF filter capacitor in them.