Motor start voltage dip workflow
How to prepare starting current, source impedance and voltage assumptions before using the Australian motor voltage-dip calculator.
Dip-estimate purpose
Motor start voltage dip links starting current with source strength. It is useful for early review of sensitive loads, generators, long feeders and weak supplies, but it does not prove acceptable starting performance.
The estimate should be recorded with the source location and current assumption that produced it.
Workflow
- Prepare the motor starting-current value and its source.
- Confirm the source impedance or source-strength assumption at the reviewed location.
- Enter the voltage basis and starting current into the calculator.
- Review the dip estimate as a planning signal.
- Escalate to network, generator, manufacturer or engineering review when performance depends on real equipment behaviour.
Voltage-dip record
| Field | Record | Review concern |
|---|---|---|
| Source location | Switchboard, feeder or generator point being assessed | Dip changes by location |
| Voltage basis | Entered nominal voltage | Percent result depends on basis |
| Starting current | A value and source | Multiplier assumptions carry through |
| Source impedance | Entered impedance or equivalent source strength | Weak source raises dip |
| Sensitive loads | Loads that may be affected | Not decided by formula alone |
Boundaries
- Do not treat a dip percentage as a network approval.
- Do not move a result between source locations without recalculating.
- Do not ignore generator, starter or motor-load dynamics.
- Do not hide whether the source impedance was measured, calculated or assumed.