User guide

49
Power Wiring, continued
External Regen
Resistor
Connection
The following diagram shows the connections between the external Regen resistor
and the 17D 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 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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