40A 63A Over and Under Protector

The Pugao 40A 63A Over and Under Protector is a specialized electrical safety device designed to safeguard circuits and connected appliances from voltage instability. Rated for standard 220VAC/230VAC systems (50/60Hz), this rail-mounted unit continuously monitors line voltage.

It automatically disconnects the power supply when voltage levels exceed safe thresholds (over-voltage) or drop too low (under-voltage), preventing damage to motors, circuit boards, and wiring. With a robust design capable of operating in temperatures from -20°C to +55°C, it ensures reliable performance in diverse environments.

Principle of operation

The principle of operation of 40A 63A Over and Under Protector is actually the monitoring of voltage data. This includes, for example, the detection and monitoring of sensors, control units, relays and other conditions.

Sensor: The voltage level can be monitored in real time. If the voltage exceeds or falls below our preset threshold, the sensor sends a signal to the control unit, prompting us to operate the process.

Control unit: can receive signals from the sensor, and will determine whether the voltage is abnormal. If the voltage is recognized to be too high or too low, the control unit will activate protective measures.

Relay: When commanded by the control unit, the relay will quickly open the circuit to protect the equipment from damage and prevent fire.

Equipment Protection

Sensitive machinery requires stable power to function correctly. The 40A 63A Over and Under Protector is widely used to protect:

• Medical Equipment: Ensuring critical diagnostic tools are not damaged by power spikes.
• Instrumentation: Maintaining the accuracy of control systems and sensors that rely on consistent voltage.

Industrial/Commercial Loads

For heavier applications, the device offers high current ratings to handle significant electrical loads:

• 40A Rating: Suitable for standard commercial lighting circuits and smaller office equipment setups.
• 63A Rating: Ideal for industrial distribution boards, heavy-duty motors, and main power feeds where higher current capacity is required.

Protection Type and Mechanism

The 40A 63A Over and Under Protector utilizes a smart control system involving sensors and relays to manage power safety:

• Over-Voltage Protection: Detects sudden rises in voltage (e.g., neutral line disconnection) and cuts power to prevent fire hazards and insulation aging.
• Under-Voltage Protection: Identifies voltage drops that can cause motors to overheat and stall, disconnecting the load to prevent burnout.
• Automatic Recovery: Once the voltage returns to a stable range, the unit can automatically re-close the circuit, reducing the need for manual intervention and ensuring continuous operation.

Advantages

Real-time voltage monitoring and quick disconnection: The 40A 63A Over and Under Protector will continuously monitor the line voltage every day, once the voltage is detected beyond the set threshold such as over-voltage or under-voltage, the protector will cut off the power supply, avoiding the electrical appliances to be permanently damaged due to high voltage or low voltage.

Extend the service life of electrical appliances: If the long-term is a stable voltage environment will reduce the electronic components due to voltage shocks caused by damage and aging, can stabilize the power supply and reduce fluctuations, to extend the overall equipment life.

Protect equipment: such as computers, medical equipment, instrumentation and control systems require high voltage accuracy. If abnormal voltage is detected it will cut off the power supply to avoid equipment data loss.

High safety and protection performance: when a sudden rise in voltage may lead to wire overheating, short circuit or fire, the 40A 63A Over and Under Protector cuts off the power supply in a timely manner at the moment of over-voltage, reduces the risk of electrical fires and improves the safety of electricity.

FAQ

How do I adjust the voltage limits?

The unit features adjustable settings, allowing you to calibrate the over-voltage and under-voltage thresholds to match the specific requirements of your connected appliances.

What is the "automatic recovery" feature?

After a fault is cleared and the voltage returns to a safe range, the 40A 63A Over and Under Protector can automatically restore power, reducing the need for manual resets and ensuring continuity.

What is the difference between 40A and 63A?

This refers to the rated current capacity. A 63A model can handle a higher electrical load (more appliances) than a 40A model. Choose based on your total connected load.

Does this protect against lightning surges?

This device is designed for over/under voltage protection. For comprehensive safety against direct lightning strikes, it is recommended to use this protector in conjunction with a dedicated Surge Protective Device (SPD).

Display and Buttons

1 - SET Button:This button is used to save after setting/changing Over-current values & high/low voltage setting values and error

wait time.

2 - UP Button: Increase the required value.

3 - Down Button: Reduce the required value.

4 - Manual On/Off Button: Used to turn the device output on or off manually. When the output is turned off, the screen will display “OFF”, and the device will be unable to perform an automatic reset. Press the button again to reactivate the device and resume normal operation (provided there is no existing fault).

5 - Current Display

1st Display Group: Under normal operation, this display shows the input (mains) voltage value. The screen stays steadily illuminated when no fault is present and will flash if a high- or low-voltage error occurs. During programming, the display indicates the relevant parameter values being set, such as overcurrent, high/low voltage thresholds, fault delay, and reset delay times.

6 - Voltage Display

2nd Display Group: During normal operation, this section shows the current value. The screen remains steadily lit when the system is functioning normally and flashes in the event of an over-current fault. During the programming process, it displays the numerical value of the corresponding program parameter.

7 - LED Indicators:

A>: Illuminates when an over-current fault is detected.

V>: Illuminates when a high voltage fault occurs.

V<: Illuminates when a low voltage fault occurs.

Out: Lights up when the device begins output operation.

Connection Diagram

The neutral and phase wires from the mains should be connected to the “N” and “L” terminals marked as “Input” on the device.

The neutral and phase wires of the equipment intended to be protected from over- or under-voltage should be connected to the “N” and “L” terminals under the “Output” section of the device.

Dimensions