Motor Controllers

Troubleshooting

Common issues and solutions for the Starter 1-Phase (SP-1P) complete single-phase smart motor starter.

Section: Starter 1-Phase

Motor Does Not Start

Cause: SP-1P contactor not energising, overload relay tripped, or app not sending command.

Confirm the SP-1P MX-1P LED is lit (green or blue). If dark, 12V DC control power is absent — check the power supply.
Confirm the device shows Online in the app before issuing a start command.
On start, the contactor should click audibly and the LED should change to solid green. If no click: check 12V DC supply is powering the MX-1P module and the RS485 connection to the gateway.
Check if the overload relay has tripped — look for a raised reset button on the front of the SP-1P assembly. Press the reset button firmly to reset the relay, then retry start.
Measure voltage at SP-1P L and N input terminals — confirm 220V AC is present. No mains voltage = motor cannot start.
Check the supply MCB — if it has tripped, investigate the cause before resetting.

Cause: Overload relay FLA dial set too low, motor drawing excess current, or capacitor fault.

Check the overload relay FLA dial on the SP-1P front panel — confirm it is set to the motor nameplate FLA, not the MCB or circuit rating.
Measure motor running current with a clamp meter on the Line conductor — if consistently above nameplate FLA, investigate the mechanical load (pump blocked, impeller worn, delivery valve closed).
For PSC or CSIR motors: check the run capacitor in the motor terminal box. A failed or undersized capacitor causes excess running current that trips the overload relay.
If the relay trips immediately on start (within 1–2 seconds): the FLA dial may be set below the motor's acceptable starting current range — verify the dial setting matches the nameplate.
After fixing the root cause, press the overload relay reset button on the SP-1P assembly, wait 60 seconds for the relay to cool, then retry.

Cause: Run capacitor fault inside the motor — SP-1P assembly does not contain the capacitor.

The SP-1P is a motor starter — it does not contain or control the run capacitor. The capacitor is inside the motor terminal box or in a separate capacitor box on single-phase motors.
Switch off the MCB and discharge the capacitor through a 10 kΩ resistor. Test capacitance with a multimeter — if more than 10% below the rated µF value, replace it.
On submersible pump motors: the capacitor is in the control box attached to the pump cable head. Replace with same µF and same or higher voltage rating (typically 440V AC).
After replacing the capacitor, restore power and retry the start command from the app.

Cause: 12V DC power absent, RS485 wiring polarity error, or Modbus address conflict.

Confirm the SP-1P MX-1P LED is lit — no LED means no 12V DC power to the module. Check the 12V DC power supply.
Swap RS485 A and B wires at one end if the device is not found after confirming power.
Check the Modbus address on the SP-1P module — if sharing an RS485 bus with other devices, confirm each device has a unique address.
Check cable continuity: measure resistance between A and B at the gateway end — should not read 0 Ω (a short prevents bus communication).
Perform a gateway RS485 scan specifically when the SP-1P LED is lit — a scan during module power-up may miss the device.

Cause: Gateway internet connection lost, RS485 cable disconnection, or 12V DC power failure.

Check the gateway Online status in the app — if the gateway is offline, all devices will show offline. Restore gateway internet connection first.
If only the SP-1P shows offline: check RS485 terminal connections at the SP-1P assembly and at the gateway. Tug wires lightly — a loose screw is the most common cause.
Power-cycle the 12V DC supply to the SP-1P assembly — the module reconnects within 60 seconds.
Check the MX-1P LED inside the SP-1P assembly — if dark, the 12V DC control power supply has failed.

LED Pattern	Status	Action
Solid Green	Starter running, RS485 connected	Normal — no action needed
Flashing Blue	Pairing mode — waiting for gateway RS485 scan	Perform RS485 scan from gateway settings
Solid Amber	Fault — overload relay tripped	Reset overload relay; check motor and load; reset fault in app
Flashing Amber	Dry-run stop active	Check water source level; reset dry-run latch in app
No LED	No 12V DC control power	Check 12V DC power supply and terminal connections