Lenze DSD - Manual (Page 370)

12 Components in the DC bus
12.6 Brake resistor selection
370
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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12.6.3 Selection table
Parameter Unit Description
Met Imp
A(P
rated
) % % Utilisation of the brake resistor relative to the rated pow-
er
Possible messages:
 Permanent utilisation of the brake chopper > 100 %
( 479)
A(P
max
) % % Utilisation of the brake resistor relative to the max. brak-
ing power
Possible messages:
 Utilisation >100 %, regarding the peak braking power
( 480)
Type Type of the brake resistor selected
R
B
Ohm Ohm Resistance value
Possible messages:
 Resulting brake resistance too low ( 481)
r
res
Ohm Ohm Resulting resistance from wiring the individual resistors
P
rated
W W Rated power of the resistor
W kWs kWs Thermal capacity of the brake resistor
• The thermal capacity describes the overload capac-
ity of a cooled brake resistor.
• The thermal capacity is provided with the technical
data of the brake resistor.
• Since the braking processes are generally very
short, the brake resistor must be able to thermally
store the energy without being damaged due to
overheating. Due to the short braking processes, it
is only able to dissipate little energy to the environ-
ment through heat radiation or convection.
τ ~
th,Rb
s s Thermal time constant for checking the brake resistor
Enclosure Enclosure of the brake resistor selected
 IP enclosure ( 371)
Thermostat Thermostat
• Information on whether the brake resistor is
equipped with a thermostat.