03.2004
Braking Resistors
Siemens AG
6SE7087-2CX87-2DA0
SIMOVERT MASTERDRIVES
Unità di frenatura / Braking Unit
4-1
4 Braking
Resistors
The braking resistors listed in chapter 7 "Technical Data" match the
braking units and allow full utilization of the braking capability.
When braking resistors and braking units are combined, it must be
guaranteed that the resistance of a resistor is not less than the
minimum allowed resistance, otherwise the braking unit may be
destroyed!
Higher values of the resistors are allowed. Under these circumstances
the braking power will be reduced (P = V
2
/R).
During operation the surface of the braking resistors may have
temperatures of several hundred degrees C. Therefore cooling air must
not contain flammable or explosive items or gases.
If a resistor is wall-mounted, the wall must not be flammable.
The external braking resistors must be installed separately and
connected on-site.
The listed braking resistors have a thermal contact (NC) which opens at
overload of the resistor. This thermal contact can, for example, be
connected up to the fault input of the SIMOVERT MASTERDRIVES.
If the thermo-contact of the external braking resistor is evaluated, the
drive converter must be isolated from the line supply when the contact
responds (e.g. by controlling the main contactor via -X9:4,5 (5-pole
terminal strip) or -X9:7,9 (9-pole terminal strip).
WARNINGS
WARNINGS
