Automation Direct DURA PULSE GS-2DBU, Руководство пользователя

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Chapter 3: Component Configuration and Wiring
3–2 DURA
pUlse
Drives Dynamic Braking User Manual – 2nd Ed., Rev.C – 06/14/2019
Operational Electrical Information
The DURa
pUlse
AC Drive and Dynamic Braking Unit will both be energized at the same time
when power is applied to the drive. (Please refer to the applicable DURa
pUlse
AC Drive User
Manual (GS3_UMW or GS4_UMW) to determine the start and stop operation of the motor.)
The Dynamic Braking Unit will monitor the internal DC bus voltage of the AC drive. When
the AC drive stops the motor by decelerating, the braking unit will detect an increase in the
drive’s DC bus voltage due to the motor causing regeneration. The braking unit will then
dissipate this excess energy into the braking resistor in the form of heat. Dissipating this
regenerated energy will allow a stable and controlled deceleration of the motor.
The alarm relay output contact terminals (RC, RA, & RB) of the dynamic braking unit will be
activated when the temperature of the braking unit heat sink exceeds 203°F (95°C) for DBUs
≤ 100hp, or 176°F (80°C) for DBUs > 100hp. This condition can be caused by the ambient
temperature surrounding the braking unit exceeding 50°C (122°F), or by the Duty Cycle
exceeding 10%. If this high ambient temperature situation exists, then a method of reducing
the ambient temperature by the use of forced air cooling or some other means should be
considered.
If the resistor does not have a temperature switch, install an overload relay between the
DBU and the resistor.
Overload Relay
For safety purposes, install an external overload relay between the dynamic braking unit
and the braking resistor. Wire the overload relay normally closed contact in series with the
coil of a magnetic contactor to interrupt the power to the AC drive.
The purpose of installing the thermal overload relay is to protect the braking resistor from
damage due to frequent braking, or due to the braking unit operating excessively due to
unusually high input voltage.
For overload relay selection information, refer to “Overload Relay Selection” in
Chapter 1, page 1–5 .