# Phase sequence and phase failure relay FF PF-431i — PF-431i, three-phase protection device

**URL:** https://aio.lv/en/product--ff-pf-431i--12111308
**Data updated:** 2026-03-20 10:03 (EET)
**Category:** Sensors & Detectors
**Manufacturer:** FF
**Manufacturer code:** PF-431i
**EAN:** 5902431672502
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 77.99 €
**Prices and availability valid until:** 2026-07-26 23:59
**Price without VAT (21%):** 64.45 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--ff-pf-431i--12111308

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 15.07.2026 | free |
| Pickup points | 20.07.2026 | 1.89 EUR |
| Courier delivery to door | 20.07.2026 | 4.99 EUR |

## Summary description

FF PF-431i is a phase sequence and phase failure relay designed for monitoring three-phase electrical networks. It detects incorrect phase sequence, phase loss and phase presence issues to protect motors and industrial equipment. The unit is mounted in control panels and provides reliable switching outputs for use in pump drives, compressors and factory automation.

## Long description

FF PF-431i is a phase sequence and phase failure relay designed to monitor three-phase electrical networks and protect motors and industrial equipment. The device continuously checks phase presence and correct phase rotation, detecting phase loss, phase reversal and phase asymmetry to trigger switching outputs that prevent damage to connected loads. Compactly mounted in control panels, the unit integrates with pump drives, compressors and automation systems where reliable three-phase supervision is required.
Advantages
The relay provides fast and reliable detection of phase loss and incorrect phase sequence with clear switching behavior, reducing downtime and equipment wear. Its compact housing and panel-mount format simplify installation in existing control cabinets. The unit offers stable operation across typical industrial supply voltage ranges and produces clean output signals compatible with common motor starters and control circuits.
Suitable for
Protection of three-phase motors and pumps against phase loss and phase reversal
Supervision of compressors and fans in industrial plants
Integration into factory automation and control panels for machinery safety
Use in motor starters, contactor control and PLC input protection
Key specifications
Function: phase sequence detection and phase failure monitoring for three-phase networks
Mounting: control panel / DIN-style panel mounting (compact housing)
Outputs: relay switching outputs suitable for interfacing with contactors and control circuits
Detection features: phase loss detection, incorrect phase rotation detection, phase presence monitoring
Application environment: designed for industrial electrical systems such as pump drives, compressors and automation equipment
How to use
Mount the relay in a control panel according to standard panel-mounting practice and connect the three-phase supply lines to the designated input terminals. Connect the relay switching outputs to the motor starter, contactor coil or control input you intend to protect. After power-up the device continuously monitors the phase sequence and presence; if a fault is detected the relay changes state to interrupt the controlled circuit or signal a downstream controller. Follow the wiring diagram supplied with the unit and ensure electrical connections and protective devices meet local regulations.
Usage recommendations
For reliable operation, confirm proper wiring and terminal tightening during installation, verify compatibility of switching outputs with the controlled equipment, and perform functional tests after installation and periodically during maintenance. Use the relay within the specified supply voltage and ambient conditions typical for industrial control cabinets.

## FAQ

### How much does the Phase relay FF PF-431i cost, and is it available for purchase?

The price is 77.99 € (valid at the time of publication and already includes all taxes). The item is available for order — 12 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 15.07.2026 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 Phase relay FF PF-431i 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 FF 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 FF 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/12111308/67647037_large.webp