Carlo Gavazzi DPA51CM44

Three-Phase Phase Sequence & Phase Loss Monitoring Relay

The DPA51CM44 is a three‑phase power monitoring relay from the DPA51 series manufactured by Carlo Gavazzi, specifically designed to detect phase sequence errors and phase loss faults in three‑phase power supplies, protecting motors and other three‑phase equipment from damage.

1. Model Code Explanation

2. Specifiche tecniche principali

3. Operating Principle & Caratteristiche
4. Operating Principle

Monitors the phase relationship of the three‑phase supply. When all three phases are present and the phase sequence is correct, the relay remains energized. If phase loss or incorrect phase sequence occurs, the relay de‑energizes immediately to trigger protection.

2. Caratteristiche principali

True RMS measurement ensures accurate detection even under non‑sinusoidal conditions

Regenerative voltage detection enables phase loss detection even when motor is rotating

Compatto 17.5 mm width saves control cabinet space

LED status indicator for quick fault diagnosis

No external power supply required; powered directly from the monitored three‑phase lines

4. Applicazioni

Suitable for all types of equipment and systems requiring three‑phase power protection, compreso:

Motor control circuits (prevents reverse rotation and phase‑loss burnout)

Elevators and lifting equipment

Air conditioning and refrigeration systems

Pumps and fan systems

Industrial automation production lines

Any electrical equipment requiring three‑phase power monitoring

5. Installazione & Cablaggio
6. Installazione

Mount on standard 35 Guida DIN da mm

Ensure adequate ventilation; avoid installation near heat sources

2. Cablaggio

Connect L1, L2, L3 to the three‑phase power supply

Connect NO (Normalmente aperto), NC (Normalmente chiuso), COM (Comune) to the control circuit

6. Sostituzione & Extended Models

7. Informazioni sull'ordinazione

Operating Principle of DPA51CM44

The DPA51CM44 is a self‑powered three‑phase phase sequence & phase loss monitoring relay. Its core function is to continuously monitor voltages on L1/L2/L3, determine whether phase loss has occurred and whether phase sequence is correct, and output a protection signal via the internal relay.

1. Power Supply Method

It does not require a separate external control power supply; it operates directly from the monitored three‑phase supply L1, L2, L3.

2. Detection Logic

Internal circuitry continuously monitors between the three phases:

Presence of voltage (phase loss detection)

Correct 120° phase difference sequence (phase sequence detection)

3. Operating Modes
4. Normal Condition (all three phases present + correct phase sequence)

Internal detection circuit confirms normal condition → output relay energizes

→ NO contact closes, NC contact opens, equipment runs normally.

2. Single‑phase or two‑phase loss

Voltage loss detected → relay immediately de‑energizes

→ control circuit is interrupted, providing protection.

3. Reversed phase sequence (incorrect L1/L2/L3 order)

Abnormal phase relationship → relay de‑energizes

→ protection is triggered to prevent motor reverse rotation.

4. Funzionalità aggiuntive

True RMS measurement ensures accurate judgment under harmonic and non‑sinusoidal conditions.

Built‑in regenerative voltage detection identifies back EMF from motor inertia to avoid misoperation.

LED indicator: ON in normal condition, OFF in fault condition for on‑site troubleshooting.

The DPA51CM44 is a three‑phase phase sequence and phase loss protection relay suitable for 208-480 VCA. It can be used in any application using three‑phase AC power where reverse rotation or phase‑loss burnout must be avoided. Typical applications include:

1. Motor Equipment (Più comune)

Tifosi, pompe dell'acqua, oil pumps, circulation pumps

Air compressors, vacuum pumps, compressori

Machine tool spindle motors, conveyor motors

Prevents winding burnout due to phase loss and motor reverse rotation caused by reversed phase sequence.

2. HVAC & Refrigeration Equipment

Central air conditioning units, water chillers

Cooling tower fans, air‑source heat pumps

Industrial refrigeration units

Prevents damage to compressors and fans from reversed phase sequence.

3. Lifting & Lifting Equipment

Ascensori, freight elevators, lifting platforms

Cranes, winches, montacarichi

Reversed phase sequence causes immediate reverse operation, creating severe safety hazards, so monitoring is essential.

4. Water Supply, Drainage & Fire Protection Systems

Fire pumps, sprinkler pumps, sewage pumps

Booster pumps, industrial circulation water systems

Ensures pumps do not reverse and shuts down promptly on phase loss.

5. Linee di produzione automatizzate & Equipment

Trasportatori a nastro, roller lines, assembly lines

Packaging machinery, food machinery, textile machinery

Injection molding machines, extruders, die‑casting machines

Maintains stable three‑phase power and avoids unexpected line stoppages or damage.

6. Construction & Power Distribution Projects

Temporary three‑phase power on construction sites

Power monitoring in distribution cabinets and power boxes

Power distribution circuits in shopping malls and factories

Quickly detects abnormal incoming three‑phase power to prevent collective failure of downstream equipment.

Almost all electromechanical equipment powered by approximately three‑phase 380 V that must not reverse or run under phase loss can use the DPA51CM44 for power protection.

Carlo Gavazzi DPA Series Three‑Phase Monitoring Relay Model List

The Carlo Gavazzi DPA series focuses on three‑phase phase sequence and phase loss monitoring, with some models offering extended functions. Below is a complete list sorted by sub‑series, including key parameters and feature descriptions.

1. Model Naming Convention

2. Complete Model List by Sub‑Series

2.1 DPA01 / PPA01 Series (ampio intervallo di tensione, including plug‑in PPA01)

2.2 DPA51 / DPA71 Series (compatto, 17.5 larghezza mm)

2.3 DPA52 Series (switching power supply, wide input range)

2.4 DPA55 Series (with voltage monitoring)

2.5 Other DPA Series Models

3. Key Feature Comparison

4. Guida alla selezione
5. Space requirement: Choose DPA51 (17.5 mm) to save control cabinet space
6. Voltage range:

208-480 VCA: select models with suffix CM44 / CM48

480-690 VCA: select models with suffix CM54 / CM58

Ultra‑wide range: select CM60 / CM69 from DPA01 series

3. Output requirement:

Single control loop: 1 SPDT (CM44 / CM54)

Dual control loops: 2 SPDT (CM48 / CM58)

4. Special applications:

Flammable refrigerant HVAC systems: select models marked HVAC

Voltage monitoring required: select DPA55 series