Exlar Tritex, Руководство по установке

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Tritex 1 Installation and Setup
130
09/27/12
PN: 27666 Exlar Corporation
Rev. M 952-500-6200M
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. Verify the
need for a shunt regulator by operating the servo under the worst case braking condition. If the
amplifier shuts off due to over-voltage (blinking red LED) a shunt regulator is necessary
(typically during downward move or deceleration).
Operation
When the DC bus reaches the shunt voltage of ~ 75 Volts 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.