Suxue SX5 Series Intelligent Digital Motor Protector

Intelligent motor protector SM502/501 digital display current overload phase sequence protection

Model	Protection Features	Output Type
Suxue SX501	Phase imbalance, phase loss, overload protection	One normally open output
Suxue SX502	Phase imbalance, phase loss, overload, stall protection	One normally open + one normally closed output
Suxue SX501-A	Phase imbalance, phase loss, overload, stall, under/over-voltage (measured via external CT)	Two normally open + one normally closed output

Operating principle:

The motor protector monitors three-phase currents while the motor is running. If any of the three-phase currents is unbalanced or missing, it delays for 3 seconds and then cuts the output power to protect the motor.

When the motor is running, the real-time current of each phase is obtained through an external CT (current transformer), and based on this current, the protector can judge overload or phase issues.

If the difference in the three-phase currents (ABC) exceeds a certain threshold, protection is triggered:

• Overload protection: If the current of any one phase exceeds the set overload threshold (e.g., 50%), a delay starts, and once the delay time is up, the output is disconnected.
• Stall protection: When the motor is stalled (locked rotor), the protector detects a current spike (4x to 8x nominal current) and shuts down the motor immediately within 0.5 seconds.
• Under-voltage protection: If the line voltage drops below 50% of the rated value, the output is disconnected.
• Over-voltage protection: If the voltage rises above 450V, output is disconnected.
• Phase imbalance protection: If the difference between any two phases is 25–50%, the output is disconnected.
• Phase loss protection: If any phase current is lower than 10%, it's treated as a phase loss and the output is cut.

Parameter Table

Code	Description	Range	Default
A	Overload protection current	2A-90A (recommended 5-10A higher than actual)	30A
F	Startup delay time	0-99 seconds	3s
H	Overload protection delay time	0, 20, 30, 40, 50 seconds (0 disables it)	30s
E	Fault reset delay time	0-99 seconds	5s
b	Power-on auto-reset	0 = No auto-reset

Note:

If no key is pressed within 10 seconds during setting, the system will exit to normal operation screen.
Long press the "Set/Unlock" button to enter setting mode, then short press to toggle parameters.
Use the "Move Left" and "Up" buttons to modify the values.

To view recorded faults:

Press "Move Left" + "Up" together to see the last fault event.

"Smart reset":

In case of a fault, long-press "Set/Unlock" for 3 seconds. If the system detects stable operation, it will auto-reset.

Main Technical Specs:

1. Power Supply: AC220V ±10%, 50Hz (AC380V ±10% optional)
2. Output contact capacity: AC220V/3A
3. External dimensions: 106mm × 86.5mm × 40mm
4. Current display range: 0–99A
5. Current setting range: 2–90A
6. Resolution: 0.1A

Important Notes:

1.      The current transformer must measure all three-phase wires of the motor — not just one.

2.      The CT wiring must strictly follow A/B/C phase sequence. Incorrect wiring will cause the device to not operate correctly.

3.      When starting the motor, the device must be powered on simultaneously to detect the inrush current and adjust settings properly. Only then will protection work as expected.

This item can be found here

This post contains affiliate links. If you click through and make a purchase, I may earn a small commission at no extra cost to you. Thank you for supporting esbangla.com!