Motor voltage sag protection device

1 Overview

Voltage sag, commonly known as shaking. Generally, due to lightning strikes, short-circuit faults, reclosing, external or internal power grid faults, and the start-up of large equipment, the effective value of the power supply voltage rapidly drops to 90% to 10% of the rated value, with a duration of 10ms to 1min. This phenomenon is called 'voltage drop', also known as' shaking '. During the voltage drop, the contacts of the contactor may pop open and cause related interlocking equipment to operate, resulting in the shutdown of the production line and causing huge economic losses to the enterprise. Voltage drop, as a special fault, has great harm, especially to enterprises that operate continuously.

Anti vibration intelligent controllerIt is a device used for electric motor control circuits. When the power grid experiences transient undervoltage and "oscillation",AC contactorAfter the main contact and self holding contact are disconnected, the controller provides auxiliary holding with delayed disconnection to the contactor. When the voltage is restored, the contactor will close again, thus maintaining the continuous operation of the motor.

Ankerui ARD-KHD-S03 seriesMotor voltage sag protection device(also known as motor low voltage oscillation protection device)It has the function of "holding and restarting under shaking power", which can resist the release of contactors caused by shaking power in the contactor control circuit (excluding DC contactors or contactors with energy-saving functions), and can also achieve restart for frequency conversion and soft start circuits, ensuring the continuous operation of equipment and safeguarding the efficient production of enterprises.

2 Product Features

Ankerui ARD-KHD-S03 seriesMotor voltage sag protection device(also known as motor low voltage oscillation protection device)It can be widely used in industries such as petrochemicals, steel, electricity, textiles, machinery, and rail transit stations.

The combination of shaking power maintenance and shaking power restart makes wiring convenient and can effectively resist contactor release caused by voltage drop

■ Anti shaking programmable settings to meet different customer needs

4 programmable DI inputs, using built-in DC24V power supply; 4-channel programmable passive DO output

■ Standard configuration includes 1 MODBUS-RTU communication channel

■ It can record 16 events each, including shaking events, switch events, contactor events, device events, power on events, and temporary rise and fall events, making it convenient for users to maintain and manage

The main body comes standard with a LCD display, and an external embedded installation display unit is also optional

External display unit supports USB program upgrade

3 Model Description

ARD-KHD-S03A and ARD-KHD-S03B are suitable for anti surge protection of contactors

ARD-KHD-S03F is suitable for anti vibration protection of frequency converter soft starter

Note: 1. Please strictly follow the recommended selection table to choose the product series suitable for the circuit!!!

2. When used for frequency conversion and soft start circuits, there is no need to select contactor current specifications.

4 Technical parameters

5. Dimensions and Installation

Main body dimensions

Display unit size

6 ARD-KHD-S03A/B action logic

7 Anti shaking electrical deviceceremonyWiring Diagram

The typical wiring of the "shaking power holding" mode is shown in the figure:

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The typical wiring for holding and restarting after shaking is shown in the diagram:

Note:

(1) The control circuit terminals 94, 95, and 96 must be strictly wired according to the wiring diagram and cannot be reversed!

(2) When using the "power shake restart" function, the DO used for restart needs to be set to "restart output".

ARD-KHD-S03F is a typical wiring diagram for frequency conversion circuits:

ARD-KHD-S03JWiring diagram for energy-saving contactors to maintain voltage fluctuation：

Control plan for frequency converter oscillation

Generally, frequency converters have protection functions for overvoltage, loss of voltage, and instantaneous power outage. The inverter device of the frequency converter is IGBT, which allows the frequency converter to continue working for a short period of time TD after voltage loss or power outage. If the voltage loss or power outage time TOTD is too long, the frequency converter self-protection stops running.

Common treatment solutions for frequency converters:

UPS power supply

Technical advantage: When there is a voltage disturbance, the battery energy storage inverter outputs a backup power supply, providing continuous power to the contactor. The power supply has no disturbance time, and the backup power supply can be converted to less than 1ms;

Technical disadvantages:UPS has poor shock resistance to the opening and closing operations of inductive loads. Poor reliability of using a single UPS power supply

Inverter self starting

Technical advantages:Cancel the low voltage protection setting of the frequency converter, set the fast restart without the need for additional input

Technical disadvantage: Low voltage often manifests as overcurrent protection for frequency converters, and canceling overcurrent protection increases the risk of damage to the frequency converter itself

DC support technology

Technical advantages:Direct DC compensation is performed at the DC end, and the frequency converter can continue to operate through DC power supply

technologydisadvantage：A large amount of battery packs need to be invested, which requires a large investment and occupies a large area of land

Control circuit voltage loss and restart

Technical advantages:When the shaking electricity causes an unexpected shutdown, the frequency converter can be automatically started, with a low investment cost, suitable for a single device

technologydisadvantage：The shutdown of the frequency converter may be caused by overvoltage, phase loss (or non control phase voltage drop). If only the control voltage is judged, it cannot meet the requirements

Soft starters are commonly used in industrial sites for high-power motors above 45kW, with functions such as soft start, soft stop, and various protections. Its function is to achieve a smooth and impact free starting motor throughout the entire starting process, prevent large currents during the starting phase, and ensure the normal start stop and service life of high-power motors

Compared to frequency converters, soft starters are essentially voltage regulators that cannot adjust frequency and speed. Frequency converters have almost all the functions of soft starters, so ARD-KHD-S03F, which is suitable for frequency converter shaking restart, is also suitable for soft starter shaking restart.