
Load-produced Negative Torque
When the H9 ASD is used with a load that produces negative torque (an overhauling load), the over- voltage or
To minimize the undesirable effects of negative torque the dynamic braking system may be used. The dynamic braking system converts the regenerated energy into heat that is dissipated using a braking resistor. The braking resistor must be suitably matched to the load. Dynamic braking is also effective in reducing the DC bus voltage during a momentary
CAUTION
If under extreme conditions the dynamic braking system or a component of this system were to fail, the dynamic braking resistor may experience an extended
To combat this condition, the
Motor Braking
The motor may continue to rotate and coast to a stop after being shut off due to the inertia of the load. If an immediate stop is required, a braking system should be used. The two most common types of motor braking systems used with the H9 ASD are DC Injection Braking and Dynamic Braking.
For further information on braking systems, see DC Injection Braking on pg. 124 and Dynamic Braking on pg. 136.
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