BLDC Pump Controller Protection Requirements: Dry-Run and Over-Current
Prepared and technically reviewed by the Sankey Engineering Team. Updated August 26, 2026.
Questions to close with the pump-system owner
Protection cannot be reviewed independently from the pump and fluid system. Confirm the expected head, flow, fluid, temperature, inlet condition, installation, duty cycle, and service response. Agree which abnormal conditions are safe to reproduce and which require a controlled emulator. A useful customer brief explains what the pump should do after dry-run, blockage, sensor loss, input interruption, or repeated restart, and how the user or service technician will know that protection has acted.
Before pilot approval, link the protection matrix to the motor, controller revision, feedback method, firmware, harness, enclosure, fixture, and records. If the pump, impeller, fluid, sensor, or pipework changes, review whether the previous evidence remains valid. This prevents a protection threshold or recovery rule from being copied into a system where the load response is different.
- Hydraulic and electrical load conditions are defined
- Fault trigger and response are observable
- Restart and reset ownership is agreed
- Engineering tests are separated from production checks
- Fluid, sensor, and pump changes trigger review
Pump-controller customers need protection behaviour that matches the hydraulic system and service reality. This guide helps OEM pump teams define dry-run, over-current, blocked-load, under-voltage, thermal, and restart requirements before selecting a controller.
Describe the pump duty and fluid
Record pump type, fluid, head, flow, startup condition, expected speed range, duty cycle, ambient, installation, and dry-run or blocked-flow risk. Include representative pump and motor samples.
A current threshold without hydraulic context is not a complete protection requirement. The same motor may draw different current as the fluid, restriction, temperature, or installation changes.
Define each protection response
For every fault, specify trigger evidence, controller response, indication, shutdown or limiting action, reset path, and retest condition. Decide whether recovery is automatic, user initiated, or service controlled.
Do not copy a universal trip time or current value from another pump. Component ratings, fluid, motor, enclosure, sensor method, and market requirements determine the approved behaviour.
Validate realistic abnormal states
Use controlled dry-run, blocked-load, repeated restart, supply variation, thermal, and sensor-loss cases where they are in scope. Record the pump, fluid, fixture, instrument, firmware, and observed response.
Protective behaviour should avoid creating a new hazard or damaging the pump. Engineering and safety owners should approve the setup and acceptance criteria before the run.
Make protection testable in production
Select safe production checks for startup, command response, fault indication, and approved recovery. Keep destructive or long-duration tests in engineering or sampling plans.
Link the protection matrix to firmware, board revision, fixture, service instructions, and failure records. A change to the pump, fluid, sensor, or enclosure should prompt an impact review.
Frequently asked questions
Can a pump controller guarantee dry-run protection for every installation?
Only within the confirmed sensing method, pump, fluid, load, and operating conditions. The final protection scope must be validated for the product.
Should protection thresholds be published on a product page?
Publish confirmed, product-specific information only. Avoid universal values that could be unsafe or misleading across different pump systems.
For a project-specific review, send Sankey your motor, load, interface, target market, and volume requirements. Review the relevant Sankey solution area before preparing a quotation request.