Introduction
This manual provides essential information for the safe and effective installation, operation, and maintenance of your Semme MS-490 Electric Motor Driven Siren Alarm Horn. Please read this manual thoroughly before using the product and retain it for future reference.
Safety Information
Always observe the following safety precautions to prevent injury or damage to the product:
- Electrical Safety: Ensure the power supply matches the specified voltage (110V) before connecting. All wiring should be performed by a qualified electrician in accordance with local electrical codes. Disconnect power before installation or maintenance.
- Sound Level: This siren produces a continuous sound pressure level of up to 150dB. Prolonged exposure to high sound levels can cause hearing damage. Wear appropriate hearing protection when operating or testing the siren.
- Mounting: Mount the siren securely on a stable surface to prevent it from falling or vibrating excessively during operation.
- Protective Mesh: Do not remove the metal protective mesh cover. It is designed to prevent injury from moving parts during operation.
Product Overview
The Semme MS-490 is a robust electric motor-driven siren designed for industrial and security applications, capable of producing a continuous 150dB alarm. Its durable construction and high-speed motor ensure reliable performance over extended periods.

Figure 1: Front-side view of the Semme MS-490 Siren.
Key Features:
- High Volume Output: Produces a continuous 150dB alarm, effective over long distances.
- Durable Motor: Dedicated motor with 10,000 rpm speed, designed for sustained operation exceeding 40 minutes.
- Protective Design: Features a metal mesh cover to prevent accidental contact with internal moving parts.
- Versatile Applications: Suitable for emergency alerts in industrial environments, cranes, ships, and various security systems.

Figure 2: Detail of the protective metal mesh cover on the siren.
Specifications
| Feature | Specification |
|---|---|
| Model | MS-490 |
| Alarm Volume | 150dB |
| Shell Color | Red |
| Operating Voltage | 110V AC |
| Housing Material | Aluminum and Steel |
| Insulation Resistance | 100MΩ (at 500 VDC) |
| Withstand Voltage | 500VAC, 50/60Hz for 1 minute |
| Motor Speed | 10,000 rpm |
| Continuous Operation | Over 40 minutes |
Setup
1. Mounting
- Select a sturdy, flat surface capable of supporting the siren's weight and resisting vibrations.
- Use appropriate fasteners (not included) to secure the siren's base to the mounting surface. Ensure all mounting points are tightened evenly.
- Position the siren to ensure the sound output is directed towards the desired area and is not obstructed.
2. Wiring
The siren requires a 110V AC power supply. Connect the power wires as follows:
- Identify the live (typically red or black) and neutral (typically black or white) wires from your 110V AC power source.
- Connect the siren's wires to the corresponding power supply wires. Ensure connections are secure and properly insulated.
- It is recommended to install an appropriate circuit breaker or fuse for protection.

Figure 3: Electrical wiring for the siren. Ensure proper connection and insulation.
Operating Instructions
Once properly installed and wired, the Semme MS-490 siren operates by applying power to its electrical connections.
- Ensure all safety precautions are observed, especially regarding hearing protection.
- Apply 110V AC power to the siren's terminals. The motor will activate, producing a continuous alarm sound.
- To deactivate the siren, remove the 110V AC power supply.
The siren is designed for continuous operation for over 40 minutes, making it suitable for extended alert scenarios.

Figure 4: The siren in operation, highlighting its 150dB sound output.
Maintenance
The Semme MS-490 siren is designed for low maintenance. Follow these guidelines to ensure longevity:
- Cleaning: Periodically clean the exterior of the siren with a dry cloth. Do not use abrasive cleaners or solvents. Ensure the protective mesh is free from debris.
- Inspection: Regularly inspect the wiring for any signs of wear, damage, or loose connections. Check the mounting for stability.
- No User Serviceable Parts: Do not attempt to open the siren housing or lubricate internal components. There are no user-serviceable parts inside. Unauthorized disassembly will void the warranty.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Siren does not activate | No power supply; Incorrect wiring; Faulty power source | Check power connections; Verify 110V AC supply; Consult a qualified electrician. |
| Weak or distorted sound | Insufficient power; Obstruction in sound path; Internal component issue | Ensure stable 110V AC power; Clear any obstructions; Contact support if issue persists. |
| Excessive vibration or noise | Loose mounting; Internal damage | Tighten mounting fasteners; Discontinue use and contact support if internal damage is suspected. |
Warranty Information
This Semme MS-490 Electric Motor Driven Siren Alarm Horn is covered by a manufacturer warranty for 90 days from the date of purchase. This warranty covers defects in materials and workmanship under normal use. It does not cover damage resulting from improper installation, misuse, unauthorized repairs, or acts of nature. Please retain your proof of purchase for warranty claims.
Support
For further assistance, technical support, or warranty inquiries, please visit the official Semme store or contact your retailer.
Semme Official Store: https://www.amazon.com/stores/Semme/page/FC2620E5-59CA-407C-9656-5FF9A3C79394





