26
| Tritex
®
TTX Series DC Actuator Installation & Maintenance Instructions
Curtiss-Wright | Rev D | PN75667 | 8/1/22
4.19 SHIELDED OR UNSHIELDED CABLES
The Tritex TTX080 can be used with either shielded or un-
shielded Ethernet cables. If a shielded cable is used it is
important that the shield is not connected at the Tritex TTX080
M12 end of the cable. Off the shelf shielded Ethernet cables
with M12 connectors usually connect the shield through the
M12 connector coupling nut, be sure the shield is not connected
to the Tritex TTX080 end of the coupling nut. The Tritex TTX080
M12 connector is in direct contact with the enclosure which
is connected directly to PE. Typically, the shield should be
connected to PE at the switch or hub end only. Connecting the
shield at both ends can cause ground loop noise on the shield
which can degrade communication performance.
For more details on the installation of an Industrial Ethernet
network download the EtherNet/IP Media Planning and
Installation Manual, found in the EtherNet/IP library at www.
ODVA.org.
5.0 MAIN POWER SUPPLY SELECTION
The Tritex TTX actuator requires DC power from a power
supply or batteries. The actuator will operate on voltages from
12-48 Vdc nominal. The continuous operating range is 10-53
Vdc. If the bus voltage rises above 85 Vdc a High Bus Fault will
occur, and the drive will disable. The voltage threshold may be
set lower through a user parameter where appropriate to protect
a power supply from overvoltage during regen. The power
supply output current rating depends on the maximum actuator
power required for the installation.
A 48 V supply will allow the motor to deliver maximum rated
speed, (specifications in Overview section) a 24 V supply will
allow the motor to deliver half the maximum rated speed, and a
12 V Supply will allow the motor to deliver quarter the maximum
rated speed.
Power supply selection and connection is complicated by
three factors associated with variable speed servo drives:
high peak loads, power regeneration (regen) and switching
frequency ripple current. Peak loads and regen will depend on
the application. Ripple current can adversely affect some power
supplies.
Note: This section does not pertain to an I/O or Holding Brake
Power Supply. The I/O supplies have different limits, and it is
often inappropriate to use the same supply for all. See section
on I/O Supply.
Power supply sizing for motion is based mainly on maximum
mechanical power delivered to the load, which is force times
velocity for linear or torque times angular velocity for rotary. The
power supply has to provide this power which is rated voltage
times maximum current plus about 20% to cover losses.
Either regulated or unregulated power supplies can be used
for the bus and logic power. Different considerations pertain to
each type, and each has advantages and disadvantages.
5.1 UNREGULATED AC/DC POWER SUPPLIES
Tritex TTX DC operates well from a transformer isolated,
unregulated DC power supply. This type of supply should be
sized and connected such that the maximum output voltage
under high-line and light-load conditions does not exceed the
drive maximum voltage rating, 48 V +10%.
Unregulated supplies have the advantage of being able to
supply peak currents without overloading and will not trip on
high voltage. Unregulated supplies have larger capacitance at
the output, especially when compared to regulated switching
supplies, providing greater energy recovery and storage during
regen and tolerating high ripple current. See section on regen
for more information on handling energy from regeneration.
They have the disadvantage of output voltage droop as the
current rises.
Unregulated supplies are usually rated only by continuous
output current. For a very short time, not exceeding 1 second,
they can typically output up to 200% of continuous current.
Voltage droop may be significant above continuous voltage
rating, which can reduce maximum speed. One sizing technique
is to calculate the required average power over the worst 5
second interval in a machine cycle, add 20% and use that to
the determine continuous rated output power for an unregulated
supply.
5.2 REGULATED AC/DC POWER SUPPLIES
Most AC/DC power supplies available today are regulated
switching power supplies. They are generally not designed to
directly power brushless DC (BLDC) drives but can do so with
special consideration for the load that BLDC drives present to
the supply and the overload characteristics of the power supply.
These supplies provide very good output voltage regulation as
well as high efficiency and smaller size and weight compared
with unregulated linear supplies.
