EARU EAATS-A Series Dual Power Automatic Transfer Switch (ATS) Instruction Manual

1. Introduction

The EARU EAATS-A series Automatic Transfer Switch (ATS) is engineered for dual-power supply systems, operating on AC 50/60Hz with rated voltages up to 400V. This device ensures an uninterrupted power supply by automatically switching to a backup power source when the main power supply fails (e.g., due to under-voltage, loss of voltage, or phase failure).

Designed with dual electrical and mechanical interlocks, the ATS prevents simultaneous connection of both power sources, guaranteeing safe and reliable operation. It is an essential component for critical applications in high-rise buildings, hospitals, fire protection systems, and industrial facilities where high power reliability is paramount.

This manual provides detailed instructions for the installation, operation, and maintenance of your ATS unit. Please retain it for future reference.

2. Important Safety Instructions

3. Product Specifications

The EAATS-A series ATS is available in 2P and 4P configurations, supporting both 110V and 220V AC systems. Key technical parameters are detailed below:

Dimensions:

• Width (2P): 108mm (4.25in)
• Width (4P): 143mm (5.63in)
• Height: 96mm (3.78in)
• Depth: 76mm (2.99in)

4. Components and Controls

The ATS unit features clearly marked terminals and indicators for easy identification and operation.

• Main Terminal of Common Power Side (Source A): Connection point for the primary power source.
• Main Terminal of Standby Power Side (Source B): Connection point for the backup power source.
• Main Terminal of Load Connection Side: Output terminals for connecting to the electrical load.
• Manual Switch Handle: Used to manually switch between Source A and Source B.
• Manual/Automatic Switching Selector: A toggle switch to select between manual and automatic operation modes.
• A Power Indicator: Illuminates when Source A is active.
• B Power Indicator: Illuminates when Source B is active.
• Main Power Terminal and Passive Signal (AC220V): Control terminals for Source A.
• Standby Power Terminal and Passive Signal (AC220V): Control terminals for Source B.

5. Installation and Wiring

The ATS can be installed vertically in a control cabinet or distribution cabinet. Ensure sufficient distance for proper ventilation and operation. The cross-sectional area of copper wires should not be less than 2.5mm².

According to the installation requirements of your power distribution system, provide appropriate circuit breakers to ensure the safety of staff and equipment.

5.1 Wiring Diagrams

Below are typical wiring diagrams for different power source configurations. Always ensure correct polarity and secure connections.

City Grid - Generator Wiring (2P)

• Common Incoming Line: Connects to the main power source (City Power).
• Standby Incoming Line: Connects to the backup power source (Generator).
• Load Output: Connects to the electrical load.
• Common Control Line: Control signal from the main power source.
• Standby Control Line: Control signal from the backup power source.

City Grid - PV Energy Wiring (Solar Energy)

This diagram illustrates the special connection mode for a photovoltaic inverter setup:

• Photovoltaic Power Station (Main Power Supply A): Connects to the inverter, then to "Normal Power A" input.
• Standby Power Supply B (City Electricity): Connects to "Reverse Power B" input.
• Ensure firing lines and zero lines are correctly connected as shown.
• Output connects to electrical equipment.

Note: The normal/backup power supply needs to be converted into 220V AC through an inverter. However, the inverter is only applicable to the mains-photovoltaic scenario, not the mains-generator and mains-mains scenarios.

City Grid - City Grid Wiring (4P)

This diagram shows a 4-pole connection for two city grid power sources. Ensure R, S, T, N connections are correctly made for both Source A and Source B.

6. Operating Instructions

The ATS unit can operate in both manual and automatic modes. The selector switch on the front panel controls the mode of operation.

6.1 Automatic Operation

In automatic mode, the ATS continuously monitors the main power supply (Source A). If Source A fails (e.g., under-voltage, loss of voltage, or phase failure), the ATS will automatically switch to the backup power supply (Source B) within milliseconds (0.008s/8ms) to ensure uninterrupted power to the load. When the main power supply is restored, the ATS will automatically switch back to Source A.

The switching logic is as follows:

1. When the normal power supply is normal, use the normal power supply.
2. When the normal power supply is cut off, automatically switch to the backup power supply.
3. When manually set to the "backup position", if the normal power supply is restored, it will still switch back to the normal power supply.
4. When both the normal power supply and the backup power supply are cut off, even if the photovoltaic power supply has power, it will not switch to the normal power supply.

Note: Manual operation must be in the "Manual" position for manual control.

6.2 Manual Operation

To manually switch between power sources, set the selector switch to the "Manual" position. Then, use the manual switch handle to select either Source A or Source B. This mode is useful for maintenance or testing purposes.

6.3 Product Demonstration Video

7. Maintenance, Inspection, and Storage

Regular maintenance ensures the longevity and reliable performance of your ATS unit. All power supplies must be cut off before any inspection or maintenance.

7.1 Inspection Items

• Check for any damaged or dirty contact parts. Clean any dust or dirt from the case.
• Verify that there are no burnt metal particles attached to and around the surface.
• Ensure that the contact surface is clean and free from rust, oxidation, and dirt to maintain good contact.
• Check for any loose parts or metal pieces.
• Measure the insulation resistance between normal supply, alternating power supply, load, and metal parts. The insulation resistance should not be less than 10MΩ.

7.2 Storage

The ATS should be stored in an environment equivalent to normal wiring equipment, which is dust-proof, moisture-proof, and corrosion-proof.

7.3 Maintenance Schedule

• The first maintenance and inspection should be carried out within 6 months after initial use.
• Subsequent maintenance and inspections should be performed at least once a year.
• Increase maintenance frequency in harsh installation conditions.

8. Troubleshooting

If the ATS unit is not functioning as expected, consider the following common issues:

• No automatic transfer: Ensure the unit is set to "Auto" mode. Check if both power sources are connected and providing the correct voltage. Verify control wiring connections.
• Power indicators not lighting up: Check the power supply to the control terminals (Main Power Terminal and Standby Power Terminal). Ensure the rated voltage is supplied.
• Unit not switching manually: Ensure the unit is in "Manual" mode. Check for any mechanical obstructions with the manual switch handle.
• Overheating or unusual smells: Immediately disconnect power from both sources. This could indicate a serious electrical fault. Do not attempt to repair yourself.

If issues persist after basic checks, it is recommended to consult a qualified electrician or contact EARU customer support.

9. User Tips

• Verify Current Rating: Before purchasing or installing, ensure the ATS unit's rated current (e.g., 100A) matches or exceeds the requirements of your electrical system. Different current ratings (e.g., 25A, 63A) may be available for specific needs.
• Professional Installation Recommended: Due to the critical nature of power transfer, professional installation by a certified electrician is highly recommended to ensure safety and compliance with local electrical codes.
• Regular Testing: Periodically test the automatic transfer function by simulating a main power failure to ensure the system is operating correctly.

10. Support and Further Information

For any questions, technical support, or further information regarding your EARU EAATS-A ATS, please contact the manufacturer directly.

An electronic version of this user manual is available for download:

Download User Manual (PDF)

This manual is for reference only. Product or version upgrades may occur without notice. The actual product prevails.