Lenze DSD - Manual (Page 368)

12 Components in the DC bus
12.6 Brake resistor selection
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Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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12.6 Brake resistor selection
The conversion of excess energy from the DC bus into thermal energy is required in order to prevent
the DC bus voltage from rising into the overvoltage range during the braking phase and thus inhib-
iting electrical braking.
• Options to dissipate or convert excessive energy:
• Feedback into the supply network via a regenerative power supply module.
• Conversion into heat via a brake resistor.
• Storage of the energy within an energy store (e. g. capacitor bank; use is rather uncommon).
• Even if there is no regenerative power, excessive energy must be dissipated, if any. In the event
of an emergency stop, for instance, the deceleration time must be longer than during normal
operation.
The following Lenze components have an integrated brake transistor which can be connected to the
brake resistor. For these components, brake resistors can be selected in DSD.
• Servo Drives 9400
• 9400 power supply module
• 9400 regenerative power supply module
• i700 power supply module
• Inverter Drives 8400
• Inverter Drives 8400 protec
• Inverter Drives 8400 motec
12.6.1 Number of integrated brake transistors
In the "Dimensioning multi-axis system" application, multiple power supply systems or regenera-
tive power supply systems connected in parallel can be selected. The number of brake transistors is
displayed for information purposes.

Danger!
Brake resistors may become very hot. Hence, the function of the brake resistor needs to
be monitored.
• In the event of an error, a mains contactor must separate the inverter or the DC bus
from the feeding supply system!
• Due to fire hazard, keep a sufficiently high safety distance between the brake resistor
and its adjacent components!
Parameter Unit Description
Met Imp
N Number of the regenerative power supply modules con-
nected in parallel with one integrated brake transistor
each.
• The selected brake resistor or the interconnection of
multiple brake resistors must be considered for every
module.
• Read only.