Regen Resistor Theory - Copley Controls Xenus Plus Series User Manual

Xenus Plus User Guide

2.13: Regen Resistor Theory

2.13.1: XEL/XPL/XML
Regeneration
When a load is accelerated, electrical energy is converted into mechanical energy. During
deceleration the conversion is reversed. This is called regeneration. Some of this regenerated
energy is lost to friction in the mechanical system. More of this energy is converted to heat due to
I2R losses in the motor windings, cabling, and drive electronics. The remainder of the energy is
added to the electrical energy already stored in the internal capacitor bank of the drive. The result
of this energy being added is an increase in the voltage on the capacitor bank.
External Regen Resistor
If too much energy is added to the capacitor bank, the voltage rises to a point where the drives over
voltage protection shuts down the drive. To prevent this, an internal transistor switch can drive an
external regen resistor to dissipate the regen energy so that the internal bus voltage is limited to a
value that permits the continued operation of the drive PWM outputs.
Regen Circuit Components
The drive provides an internal transistor that is used in combination with an external resistor.
Copley Controls supplies compatible resistors as described in
165). When using a resistor acquired from another source, be sure it meets the specifications
described in Regen Resistor Sizing and Specification (p.
Regen Circuit Protections
The drive protects the regen circuit against short circuits and uses I
to protect both the external resistor and the internal transistor.
Configurable Custom Resistor
The following values can be entered for a custom resistor using CME:
Option
Resistance Value
Continuous Power
Peak Power
Time at Peak Power
For more information, see
Copley Controls
Description
Value in Ohms of the resistor
Continuous power rating of the resistor
Peak power rating of the resistor
Time at peak power of resistor
Regen Resistor Sizing and Specification (p.
16-01344 Rev 06
Regen Resistor Assemblies (p.
134).
2
T peak current/time algorithms
134).
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