Curtiss-Wright | Tritex II DC Rev. J PN49220 2/8/2016
26
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.
Due to overcurrent protection, regulated supplies must generally be
rated for the peak power required by the drive. Because the supplies limit
output current, fuses between power supply and drive may not be able to
interrupt fault current to the drive. The power supply must have output
current foldback and / or output cycling on overload. Foldback is where
the output current limit is reduced more or less proportionally with the
output voltage. Output cycling removes all output power on overload and
waits a few seconds before attempting to restore power, limiting average
power during faults. Fuses can still be very useful in isolating a fault
when a large power supply is used to power several loads. Where
conditions of use by an approval agency require fuse protection, the
fuses must be installed even if they would not immediately clear a fault.
During deceleration of the load the energy generated
from the motor and the load will increase the bus
voltage and could possibly damage the output of a
regulated power supply. If a regulated power supply is used for bus
power, a blocking diode should be installed to protect the power
supply. See Power Supply Wiring Diagrams section below
Regenerative energy due to deceleration, spring action, or gravity on
the mechanical load will increase bus voltage and attempt to drive
energy backward into a power supply. Regulated supplies may trip on
overvoltage or recover slowly after being out of regulation causing a dip
in output voltage at the end of a regen event. It may be necessary to use
a blocking diode to allow the bus voltage at the drive to rise above
normal supply voltage without any reverse current. Exlar offers a Power
Distribution and Surge Filter assembly that include a blocking diode,
TDCESF1 (see Accessories section). See the section below on Handling
Regen Energy
Another aspect of BLDC drive loads is that it tends to take pulses of
current at twice internal switching frequency creating high ripple current.
Some regulated supplies may not be able to tolerate high ripple current,
depending on the final filter capacitors. The Power Distribution and
Surge Filter assembly includes a small inductor that reduces ripple
current. The blocking diode (if used) also reduces ripple current. Power
wiring or power cables more than 30 ft (10 m) long provide enough
impedance to reduce ripple current as well. Contact Exlar applications
support for additional information.
CAUTION
Summary of Contents for Tritex II DC Series
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Page 10: ...Curtiss Wright Tritex II DC Rev J PN49220 2 8 2016 10 EU Declaration of Conformity for CE Mark...
Page 19: ...Curtiss Wright Tritex II DC Rev J PN49220 2 8 2016 19 Dimensions...
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Page 53: ...Curtiss Wright Tritex II DC Rev J PN49220 2 8 2016 53 Cable Shield Grounding Example...
Page 62: ...Curtiss Wright Tritex II DC Rev J PN49220 2 8 2016 62 ACCESSORIES Cables TTIOC xxx I O Cable...
Page 63: ...Curtiss Wright Tritex II DC Rev J PN49220 2 8 2016 63 TTIPC xxx Power Cable...
Page 64: ...Curtiss Wright Tritex II DC Rev J PN49220 2 8 2016 64 TTICO xxx Communications Cable...
