Schneider Electric Lexium 17S Series - Manual (Page 63)

51
Power Wiring, continued
Optional
External Regen
Resistor
Connection The following diagram shows the connections between the optional external Regen
resistor and the 17S drive. The drive is shipped with a jumper installed on
connector X8, terminals R
B
and R
Bint
. If you are going to use an optional external
Regen resistor, then remove the jumper to disconnect (and thus disable) the
internal Regen resistor.
Fusing of the two lines to external Regen Resistor is mandatory.
Use high voltage AC/DC and fast fuses.
Regen Circuit
Functional
Description During braking, energy from the servo motor is returned to the drive and converted
into heat in the Regen resistor. Operation of the Regen resistor is controlled by the
Regen circuit using thresholds that are adjusted to the main supply voltage that is
configured in the UniLink software. The following is an abbreviated functional
description of the Regen circuit operation.
l Individual drive (not coupled through the DC Link circuit) - The circuit starts to
respond at a DC Link voltage of 400V, 720V or 840V (depending on the supply
voltage). If the energy fed back from the servo motor is higher than the preset
Regen power, then the drive issues a "Regen power exceeded" signal and the
Regen circuit will be switched off. Upon the next internal check of the DC Link
voltage, an overvoltage will be detected, the fault relay contact will be opened
and the drive will be switched off with the error message "Overvoltage".
l Multiple drives (coupled through the DC Link circuit) - In this case, the Regen
energy is distributed equally among all the drives.
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