1
Star-Delta Timer Configuration
The star-delta transition timer determines how long the motor runs in star before switching to delta. Setting it correctly is the most important configuration step for the SP-3P-SD — too short causes a current spike on transition; too long causes the motor to overheat in star.
- 1Navigate to Device Settings → Motor → Star-Delta Timer.
- 2Recommended starting values by motor size:
- 3• Up to 11 kW (15 HP): 5–8 seconds
- 4• 11–22 kW (15–30 HP): 8–12 seconds
- 5• Above 22 kW (30 HP+): 12–20 seconds — confirm with motor manufacturer data if available
- 6Measure motor current during the star phase with a clamp meter — the current should be falling (motor accelerating) by the end of the star period. If still rising at transition time, increase the timer.
- 7Set the transition pause at Device Settings → Motor → Transition Pause. Default is 50 ms — do not reduce below 50 ms. This pause between star opening and delta closing prevents a supply short-circuit.
- 8Monitor the current spike at transition — a sharp spike indicates the motor has not reached sufficient speed in star. Increase the star timer by 2 seconds and retry.
2
Overload Relay Setup
Set the overload relay FLA dial to the motor delta running current — the same as the motor nameplate FLA at 415V. Do not set it to the star current or to a fraction of the DOL current.
- 1Locate the motor nameplate FLA at 415V — this is the delta full-load current.
- 2Set the overload relay dial on the SP-3P-SD assembly to this value.
- 3The overload relay protects the motor in delta (full-load) running. It does not need to be set for the reduced star-phase current.
- 4Verify actual delta running current with a clamp meter after first successful transition — confirm within 10% of nameplate FLA.
3
Phase-Loss Protection
- 1Phase-loss protection is active by default when R, S, T sense wires are connected to the MX-3P-SD phase sense terminals.
- 2Trip delay: Device Settings → Motor → Phase Loss Delay (default: 2 seconds). Increase to 5 seconds if the supply has frequent momentary dips.
- 3A phase-loss event during the star phase or delta running triggers an immediate stop and alert. The fault is latched — manual reset required in the app at Device → Reset Fault.
- 4Phase imbalance monitoring: configure threshold at Device Settings → Motor → Phase Imbalance Threshold — a 5% imbalance warning is logged even without full phase loss.
4
Motor Protection Settings
- 1RESTART DELAY: Device Settings → Motor → Restart Delay. Recommended: 120 seconds for star-delta started motors — allows motor to fully decelerate and the star-delta assembly to cool between starts.
- 2RUNTIME LIMIT: Device Settings → Motor → Max Runtime. Motor stops and alerts if exceeded without a stop command.
- 3FAULT LATCH: Enable at Device Settings → Motor → Fault Latch. Prevents automatic restart after any hardware or software protection trip.
5
Dry-Run Protection, Scheduling & Alerts
- 1Dry-run protection: Requires HPzenAi LS-PRE level sensor on the same gateway. Automation → Add Rule → Level Sensor Low → Stop Motor. Add a 5-minute wait before auto-restart to allow bore recovery.
- 2Scheduling: Device → Schedules → Add Schedule. Set Daily or Weekly with Start Time and Stop Time.
- 3PHASE LOSS ALERT — set to High priority: Device → Alerts → Phase Loss Alert → Priority: High.
- 4TRANSITION FAIL ALERT: Sent when the MX-3P-SD detects a failure to transition from star to delta. Configure at Device → Alerts → Transition Fail Alert.
- 5OVERLOAD TRIP ALERT, DRY-RUN ALERT, RUNTIME ALERT, and OFFLINE ALERT are also available under Device → Alerts.
- 6All events — including each star-delta transition sequence — are logged in Device → Event Log with timestamps.