Description

PR3-O-225kW 415V Three-Phase Burst Fire Power Regulator

The PR3-O-225kW is a heavy-duty three-phase burst fire power regulator designed to provide seamless control of high-power resistive loads using advanced two-thirds control technology. Engineered for demanding HVAC and industrial heating applications, it delivers accurate power regulation while reducing flicker and eliminating radio frequency interference (RFI) through fast pulse zero-voltage switching.

Designed for continuous operation in high-capacity heating systems, the PR3-O-225kW incorporates integrated semiconductor fuses, automatic thermal protection, comprehensive fault monitoring, and a permanently operating cooling fan for dependable long-term performance. Flexible control input options and selectable burst firing modes make it suitable for a wide variety of industrial process heating applications.

With robust construction, easy installation, and advanced protection features, the PR3-O-225kW is an ideal solution for controlling large resistive loads in HVAC air curtains, industrial furnaces, ovens, dryers, and other high-power heating systems.

Key Features

• Seamless three-phase control using two-thirds control technology
• Fast pulse zero-voltage switching to minimise flicker and eliminate RFI
• Selectable fast burst (flicker inhibited) or slow burst firing operation
• DC signal or manual potentiometer control
• Automatic reset over-temperature protection
• Integrated high-speed semiconductor fuses
• Voltage-free alarm relay for remote fault indication
• Phase loss and temperature sensor fault detection
• Permanently operating forced-air cooling fan
• Easy-access signal and power terminals for straightforward installation
• Suitable for floating-star and closed-delta resistive load configurations

Technical Specifications

Electrical

• Power rating: 225kW (313A)
• Supply voltage: 415V RMS nominal
• Input voltage: 400V RMS ±10%
• Frequency: 50/60Hz

Control Input Options

• 0–10V DC (factory default)
• 0–5V DC
• 4–20mA input
• Manual control via 5kΩ potentiometer

Burst Fire Control

• Fast burst firing (flicker inhibited)
• Slow burst firing (1-second proportional time base)

Alarm & Monitoring

• Voltage-free alarm relay
• Alarm relay rating:
  • 2A @ 125V AC
• Configurable relay operating modes (normally open or normally closed)
• Status LED tracks output activity
• Remote alarm supply option (24V AC/DC)

Protection Features

• Automatic over-temperature trip activates at:
  • 90°C ±1°C
• Automatic reset temperature:
  • 85°C ±1°C
• Phase loss detection
• Temperature sensor loss detection
• Integral high-speed semiconductor fuse protection

Cooling

• Permanently operating 120mm cooling fan
• Standard 230V AC fan
• Optional 110V AC or 24V AC fan available

Terminal Connections

Phase Power

• M8 setscrew with nut and washer

Earth

• M6 stud with nut and washer

Auxiliary Alarm Relay

• 2.5mm² rising clamp terminal block

Control Signal

• 2.5mm² rising clamp terminal block

Torque Settings

• Power and earth terminals:
  • 12–15Nm

Fusing

• 355A High-Speed Semiconductor Fuse (355MT or equivalent)

Environmental

• Maximum operating temperature:
  • 65°C

Mechanical

Dimensions

• 260mm (D) × 245mm (W) × 215mm (H)

Fixing Centres

• 141mm (W) × 170mm (L)
• Alternative mounting:
  • 141mm (W) × 100mm (L)

Weight

• 6.5kg

Applications

Suitable for 3-wire, three-phase floating-star or closed-delta configured resistive loads, including:

• HVAC air curtain systems
• Industrial furnaces
• Industrial ovens
• Dryers
• Hot plates
• Process heating equipment
• Commercial heating systems
• High-capacity industrial heating applications
• Large resistive load temperature control systems