Definition
DC-link overvoltage is a specific fault condition where the voltage in a drive's DC link rises above its safe operating limit (commonly caused by a motor decelerating faster than the load can absorb the regenerated energy, or by a supply voltage disturbance) triggering a protective trip to prevent damage to the DC link capacitors and other components.
Key facts
- A specific, named fault condition affecting the DC link stage specifically, not a general electrical overload symptom.
- Commonly caused by regenerative energy from rapid deceleration exceeding what the system can absorb or dissipate.
- Often addressed by adding a brake resistor to dissipate excess regenerated energy, or by adjusting deceleration ramp settings.
- A protective trip in response to this fault is a designed safety response, not itself the underlying problem to fix.
How does DC-link overvoltage work or appear?
DC-link overvoltage means the voltage within a drive's DC link has exceeded its rated safe limit, most commonly because a motor decelerating quickly acts as a generator, feeding energy back into the DC link faster than it can be dissipated or absorbed, triggering the drive's protection to trip and prevent capacitor or component damage.
What should technicians inspect for DC-link overvoltage?
Addressing DC-link overvoltage typically involves adding or verifying a brake resistor to dissipate excess regenerated energy during deceleration, adjusting the deceleration ramp time to reduce the rate of energy regeneration, or investigating supply-side voltage disturbances if those are contributing to the condition.
FAQ
Frequently asked questions
What does an excessive DC-link voltage mean?
It means the DC-link voltage inside a drive has risen above its safe limit, commonly due to regenerative energy from rapid deceleration exceeding what the system can dissipate, triggering a protective trip.
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