1
Overload Relay Setup
Setting the built-in overload relay FLA correctly is essential. An incorrectly set overload relay is the leading cause of both motor damage (set too high) and nuisance trips (set too low) in three-phase motor installations.
- 1Locate the motor FLA (Full Load Amperes) on the motor nameplate — labelled 'A', 'FLA', 'I', or 'Rated Current' at the rated voltage (415V).
- 2Set the FLA dial on the SP-3P overload relay section to the motor nameplate FLA.
- 3Do NOT set the dial to the supply MCB rating or the contactor Ie rating — use the motor nameplate value only.
- 4If the motor has a Service Factor (SF) > 1.0, the overload relay can be set up to SF × FLA.
- 5After commissioning, verify actual running current with a clamp meter on each phase — all three phases should read within 5% of each other and within 10% of nameplate FLA.
2
Phase-Loss Protection
- 1Phase-loss protection is active by default once R, S, T sense wires are connected to the MX-3P phase sense terminals.
- 2Configure trip delay at Device Settings → Motor → Phase Loss Delay (default: 2 seconds). In areas with frequent momentary supply dips, increase to 5 seconds to avoid nuisance trips.
- 3After a phase-loss trip, the motor will not restart automatically — reset the fault latch in the app at Device → Reset Fault before restarting.
- 4Phase imbalance warning: configure threshold at Device Settings → Motor → Phase Imbalance Threshold. Sustained imbalance above 5% is logged as a warning even if no phase is fully lost.
3
Motor Protection Settings
- 1RESTART DELAY: Device Settings → Motor → Restart Delay. Recommended: 60 seconds for three-phase induction motors to allow full deceleration before re-start.
- 2RUNTIME LIMIT: Device Settings → Motor → Max Runtime. Motor stops and alerts if this run time is exceeded without a stop command.
- 3FAULT LATCH: Enable to require manual app reset after any hardware trip (overload relay, phase loss, dry-run). Prevents automatic re-start onto a faulty mechanical load.
4
Dry-Run Protection
- 1Requires an HPzenAi LS-PRE level sensor in the water source, linked to the same gateway.
- 2Automation → Add Rule → Trigger: Level Sensor Low → Action: Stop Motor [SP-3P name].
- 3Optional restart rule: Trigger: Level Sensor Restored → Wait 5 minutes → Action: Start Motor (allow bore to recover).
- 4Set a dry-run confirmation delay on the rule to avoid false trips from momentary sensor fluctuations: Trigger: Level Low → Wait 2 minutes → Stop.
- 5Test by simulating Level Low in the app — confirm the SP-3P stops the motor within the configured delay.
5
Scheduling & Alerts
- 1Device → Schedules → Add Schedule. Set Daily or Weekly with Start Time and Stop Time.
- 2PHASE LOSS ALERT — set to High priority: Device → Alerts → Phase Loss Alert → Priority: High.
- 3OVERLOAD TRIP ALERT: Device → Alerts → Fault Alert. Sent when the overload relay trips and motor stops unexpectedly.
- 4DRY-RUN ALERT: Sent when level sensor triggers a dry-run stop.
- 5OFFLINE ALERT: Device → Alerts → Offline Alert. Configure timeout (recommended: 5 minutes).
- 6All alert events and phase status readings are logged in Device → Event Log.