28
| Tritex
®
TTX Series DC Actuator Installation & Maintenance Instructions
Curtiss-Wright | Rev D | PN75667 | 8/1/22
In the example below a single 24 V regulated supply is used
for main power (BUS+), and Digital I/O. Logic power is derived
internally from the bus power. The 24 V regulated supply will
keep the I/O voltage under the 30 V limit but not within limits
for the brake option, so may not be suitable for units with a
brake. Notice there is no external diode, isolating the power
supply from the Bus voltage. For this example, set the User
Overvoltage Fault Limit to 33 V. The Tritex TTX shunt regulator
will attempt to limit the Bus Voltage to 30 volts (90% of 33 V) to
Digital Common
Digital Power
protect the power supply from overvoltage faults & shutdowns
and the I/O from overvoltage. If the regen energy is too large,
the shunt regulator will turn off to protect itself and a high bus
voltage fault will occur at 33 V, disabling the drive and protecting
the power supply and I/O circuits.
Unregulated supplies often have very large capacitors that
can store regen energy if allowed to be back driven. This
characteristic can be used in conjunction with the internal shunt
resistor and regulator. The shunt operating point is set to the
working voltage of the capacitors. Regen energy is stored in
the capacitor until its voltage rises to the shunt operating point.
Then the internal shunt accepts up to 10 J of additional energy.
5.5 HANDLING REGEN ENERGY – EXTERNAL SHUNT
RESISTOR AND REGULATOR
For applications lowering vertical loads or decelerating a large
inertia or working to hold back some force, regen energy will
exceed the ability of the internal shunt resistor and power
supply to dissipate or store it.
5.6 LOGIC POWER SUPPLY
A logic power supply can be used to maintain the control and
position information with bus power removed. This power
supply is optional and requires about 2 W of power. It is wired to
the Logic Power terminal (+) and Power Common terminal (-).
If it is not connected the logic power will come from bus power.
Note that the main power and logic power share a return path.
Logic Power can be the same wide range as the main power
supply, 12 V, 24 V, or 48 V nominal, and can handle the regen
voltages that appear on the main supply. A single supply may
be used for both with a relay contact in series with the main
supply positive connection to remove bus power. As long as the
main power supply and an I/O Supply have negative terminals
grounded, the I/O supply may be used for logic power.
5.7 POWER SUPPLY WIRING DIAGRAMS
WARNING!
All installations should provide a method of
removing bus power during an emergency stop condition. The
actuator enable function should not be relied on for this function
when equipment or personnel safety is required. Disconnect
only the + bus power; do not disconnect the – bus power.
Figure 29
–
Un-Regulated Power Supply for Logic and Bus
Power
Figure 30
–
Regulated Power Supply for Logic and Bus Power,
with Diode Isolation and Optional Extra Capacitance
Figure 31
–
Unregulated Power Supply for Logic and Bus
power, with a Shunt Regulator example
