Exlar Tritex II DC Series, Инструкция по установке и обслуживанию

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Curtiss-Wright | Tritex II DC Rev. J PN49220 2/8/2016 67
Shunt Regulator
TTSR1 Shunt Regulator Option
Transient over voltage problems are quickly solved using shunt
regulators that clamp regeneration voltage to safe levels. These simple
devices can increase system reliability by stabilizing voltage fluctuations
and eliminate over-voltage shutdowns.
The purpose of a shunt regulator is to 'burn off' excess regeneration
energy that is produced when a drive brings a large load to a stop.
Mechanical braking systems use friction to stop a load and convert
kinetic energy into heat. Servo drives on the other hand are very efficient
power converters - typically over 98%! They convert electrical energy
from the motor to the power supply just as efficiently as when they
convert energy from the power supply to the motor. During a rapid
deceleration or the deceleration of a large load, enough excess energy
can be transferred to shut down the drive or damage the power supply.
A shunt regulator 'clamps' the power supply voltage to a set level and
prevents unexpected shutdown or damage. It monitors the power supply
voltage and if the voltage exceeds the set limit, the shunt regulator
'bleeds off' the extra voltage through a power resistor. The shunt
regulator is only active when the voltage exceeds the set level;
otherwise, no current passes through the power resistor. The shunt
regulator automatically turns the power resistor on and off as necessary
to regulate the voltage, sometimes up to several hundred Hertz.
Description
The TTSR1 shunt regulator is designed to work with four quadrant
regenerative servo amplifiers.. 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 amplifier’s
over-voltage shutdown point, motor control and braking will cease. To
ensure smooth braking of large inertial loads with use of a shunt
regulator is recommended. If the Tritex indicates an overvoltage fault
there is an need for a shunt regulator. This regulator is designed to
operate with power supplies that can > 75 volts without damage or
shutdown, typically and unregulated supply.
Operation
When the DC bus reaches the shunt voltage of ~ 77V 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
hysteresis loop allows time between switching. If the voltage goes above
85V the Tritex will trip on a High Bus Voltage fault and disable the drive.
See Faults section.