Rockwell Automation 1398-DDM-xxx USE MNL/ULTRA 200 DIG.SERVO.DR - Manual (Page 121)

Publication 1398-5.0 – October 1998
Power Connections 7-11
TB2 – Shunt Regulator
The ULTRA 200 Series drive has a built-in shunt regulator. The figure
depicts the internal shunt selection with a factory installed jumper
between terminals TB-1 and TB-2. Removal of the internal shunt
jumper and installation of an external shunt between terminals TB-1
and TB-3 allows voltage to be dissipated at a faster rate than possible
with the internal shunt.
The shunt regulator is enabled when the DC bus increases to a specific
value (420 VDC). An increase in DC bus voltage always occurs when
the drive decelerates the motor and its load. This is due to the current
flow from the motor to the DC bus. When the energy transferred from
the rotating inertia causes the DC bus voltage to exceed 420 VDC the
shunt is enabled and the excess energy (>420 VDC) is dissipated as
heat.
Terminal Identifier Description
TB2-1 1
(Internal
or
External) Positive DC bus
TB2-2 2
(Internal) Internal shunt
regulator resistor
TB2-3 3
(External) Shunt regulator
transistor collector
!
Intro
ATTENTION: High voltage is present on the terminals
of the ULTRA 200 Series drive. Remove power and dis-
connect the power cable before making or removing any
connection. Failure to observe this precaution could result
in severe bodily injury or loss of life.
!
Intro
ATTENTION: DC bus capacitors may retain hazardous
voltages for several minutes after input power has been
removed, but will normally discharge in several seconds.
Measure the DC bus voltage to verify it has reached a safe
level each time power is removed before working on the
drive; or wait for the time indicated in the warning on the
front of the drive. Failure to observe this precaution could
result in severe bodily injury or loss of life.
!
Intro
ATTENTION: External shunt resistors connect directly
to the power bus. For safety reasons, an external shunt resis-
tor must be enclosed.
1
2
3
INT
E
R
NAL
EXT
ERNAL
SHUNT