901 PHT 24 50 420 AL5, Unison Scr, Input 4-20ma, output 240vac, 50amp

Product Description

The Unison 901 PHT 24 50 420 AL5 is a 50 Amp Analog SCR Power Controller designed for accurate and proportional control of AC power in industrial heating and automation applications. Unlike conventional ON/OFF solid state relays, this controller uses phase angle firing technology to continuously regulate the amount of power delivered to the load. This provides smooth temperature control, minimizes power fluctuations, and improves process efficiency, making it an ideal choice for precision heating applications.

This SCR power controller accepts a 4–20 mA analog input, allowing direct connection to PID temperature controllers, PLC analog output modules, DCS systems, and other industrial control equipment. It controls 230/240 VAC single-phase loads up to 50 Amps, making it suitable for electric heaters, industrial ovens, furnaces, dryers, plastic processing machinery, packaging equipment, and textile machines. The AL5 aluminium base plate provides excellent thermal conductivity and ensures efficient heat transfer to the external heat sink for reliable long-term operation.

The 901 PHT 24 50 420 AL5 incorporates back-to-back SCR technology, providing smooth linear power regulation throughout the complete input range. It features 6 kV input-to-output isolation, 4 kV body insulation, built-in 2700 Vrms surge protection, and short-circuit protection using a B-curve DP MCB, making it suitable for demanding industrial environments. Compared to conventional contactors, the controller offers silent operation, fast response, maintenance-free performance, and significantly longer service life.

Its compact 45 mm industrial housing enables easy installation inside electrical control panels, while DIN rail compatibility simplifies panel assembly. For reliable continuous operation at higher loads, Unison recommends using the G-68 heat sink or a larger heat sink depending on the application.

Key Features

• Model: 901 PHT 24 50 420 AL5
• Brand: Unison
• Analog SCR Power Controller
• Phase Angle Control
• Rated Load Current: 50 Amp
• Control Input: 4–20 mA
• Output Voltage: 230/240 VAC
• Smooth proportional power control
• Back-to-back SCR technology
• Built-in surge voltage protection
• Short-circuit protection using B-curve DP MCB
• 6 kV input-to-output isolation
• Compact 45 mm industrial housing
• DIN rail compatible

Technical Specifications

Applications

The Unison 901 PHT 24 50 420 AL5 is ideal for:

• PID temperature control systems
• Electric resistance heaters
• Industrial ovens and furnaces
• Infrared heater control
• Plastic extrusion and injection moulding machines
• Packaging and sealing machines
• Textile processing equipment
• Food processing machinery
• Industrial dryers
• Laboratory heating equipment

Why Buy from Voltkart?

• Genuine Unison SCR Power Controllers
• GST Invoice provided
• Pan India delivery
• Bulk pricing available for OEMs, machine builders, and panel manufacturers
• Expert technical support for product selection
• Trusted supplier of industrial automation components

Frequently Asked Questions

1. What is the difference between this SCR controller and a standard SSR?

A standard SSR only provides ON/OFF switching, whereas the 901 PHT 24 50 420 AL5 offers phase angle control, allowing proportional power regulation for highly accurate temperature control.

2. Which control signal is required?

This model accepts a 4–20 mA analog input, making it compatible with PID controllers, PLC analog outputs, and DCS systems.

3. Is a heat sink required?

Yes. For continuous operation, Unison recommends using the G-68 heat sink or a larger heat sink depending on the operating current and ambient temperature to ensure reliable performance.

Related Products & Collections

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