# Siemens SIRIUS 3UG5618-1CR21 Digital Voltage Monitoring Relay, 3-Phase, 90-690V AC, 2CO

**URL:** https://aio.lv/en/product--siemens-3ug5618-1cr21--12469041
**Data updated:** 2026-05-18 09:43 (EEST)
**Category:** Sensors & Detectors
**Manufacturer:** Siemens
**Manufacturer code:** 3UG5618-1CR21
**EAN:** 4047621099989
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 230.49 €
**Prices and availability valid until:** 2026-08-01 23:59
**Price without VAT (21%):** 190.49 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--siemens-3ug5618-1cr21--12469041

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 22.07.2026 | free |
| Pickup points | 27.07.2026 | 1.89 EUR |
| Courier delivery to door | 27.07.2026 | 4.99 EUR |

## Summary description

The Siemens SIRIUS 3UG5618-1CR21 is a digital voltage monitoring relay designed for 3-phase systems. It operates within a voltage range of 90-690V AC and a frequency range of 15-70Hz. Featuring 2 changeover contacts (2CO) and screw terminals, this device provides reliable phase sequence monitoring and protection. It is an essential component for industrial automation and electrical safety systems requiring precise voltage control.

## Long description

The Siemens SIRIUS 3UG5618-1CR21 is a high-precision digital voltage monitoring relay engineered for robust 3-phase electrical systems. This versatile device provides comprehensive protection by monitoring phase sequence, phase failure, asymmetry, frequency, as well as over-voltage and under-voltage conditions. Designed for global industrial applications, it supports a wide voltage range from 90V to 690V AC and a frequency range of 15-70Hz, ensuring reliable operation even in unstable power environments.
Advantages
This monitoring relay offers significant operational benefits, including the ability to perform phase sequence correction, which simplifies installation and prevents motor damage. The digital interface allows for precise parameterization of threshold values, delay times, and reset behaviors, providing users with granular control over their electrical infrastructure. Its slim, space-saving design makes it ideal for compact control cabinets, while the integrated display provides real-time diagnostics by showing actual values and specific fault types. Furthermore, the device is certified for SIL 1/PL c, ensuring high safety standards for critical industrial processes.
Suitable for
Industrial automation systems
Mobile systems such as A/C compressors and refrigerated containers
Construction site machinery and cranes
Photovoltaic systems and wind turbines
Applications requiring phase sequence and voltage stability monitoring
When it may not be suitable
This device is specifically designed for 3-phase AC systems and is not compatible with single-phase power supplies or DC circuits. It may not be suitable for environments where the required safety integrity level exceeds SIL 1/PL c or where communication protocols other than standard relay outputs are strictly required without additional adapters.
Key specifications
Voltage range: 90-690V AC
Frequency range: 15-70Hz
Contacts: 2 changeover contacts (2CO)
Connection type: Screw terminals
Safety certification: SIL 1/PL c
Monitoring functions: Phase sequence, phase failure, asymmetry, frequency, over-voltage, under-voltage
How to use
Installation should be performed by qualified personnel in accordance with local electrical regulations. The device is mounted on a standard DIN rail within a control cabinet. Once mounted, connect the 3-phase power lines to the designated screw terminals. Use the digital interface on the front of the unit to set the desired monitoring parameters, such as voltage thresholds and time delays. The display will indicate the current status and any detected faults, allowing for quick troubleshooting and system adjustment.
What to consider before purchase
Ensure the supply voltage of your system falls within the 90-690V AC range.
Verify that the 3-phase configuration matches the relay requirements.
Confirm that the screw terminal connection is appropriate for your wiring standards.
Check if the SIL 1/PL c safety rating meets your specific project requirements.
Usage recommendations: Regularly check the display for any logged fault codes to ensure proactive maintenance. Ensure that the terminals are tightened correctly to prevent vibration-related issues in mobile or high-vibration environments.

## FAQ

### How much does the Siemens SIRIUS 3UG5618-1CR21 Voltage Monitoring Relay cost, and is it available for purchase?

The price is 230.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 3 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 22.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay, Installment. All transactions are 100% secure and encrypted.

### Can Siemens SIRIUS 3UG5618-1CR21 Voltage Monitoring Relay be purchased with a lease?

Yes, the purchase is available both on credit and with an interest-free installment plan. Learn more about installments and credit options: https://aio.lv/en/payment#b3

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All Siemens products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized Siemens service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

## Image

https://aio.lv/img/cache/product/12469041/68795141_large.webp