Description

Multi-turn Electric Actuator Overview

The multi-turn electric actuator must guarantee absolute reliability when process uptime is critical. The BD250-C8 series from Bonray exemplifies this principle through robust engineering, specifically designed to withstand the rigors of demanding industries such as power generation, petrochemical, and water treatment. To achieve this, our manufacturing process emphasizes a dual-seal philosophy—from the main housing to the terminal box—ensuring an IP68 rating that protects against prolonged submersion. Additionally, the internal gear train is filled with high-grade lubricant at our factory, eliminating the need for routine maintenance and drastically reducing total cost of ownership. As a result, we designed this actuator to deliver precise torque control and fail-safe operation, ensuring that critical valves operate correctly every time.

Multi-turn Electric Actuator Features

• High-Grade Mechanical Lubrication: The actuator requires no lifetime oil changes. We seal the gearbox with premium lubricant that ensures smooth operation and minimizes wear over tens of thousands of cycles.
• Dual-Seal Terminal Box: This innovative feature allows maintenance personnel to connect cables without exposing the main control board to moisture or dust. Even with the terminal cover removed, a secondary seal keeps the electronics safe.
• Large LCD Display with Alarm Log: The screen does not just show current position; it stores a log of historical alarms and operations. This facilitates troubleshooting, allowing technicians to understand the sequence of events leading up to a fault.

  

Multi-turn Electric Actuator Protect Functions

• Valve Jam Protection: When starting from a seated position, the actuator temporarily ignores torque alarms for a few seconds to provide the necessary impulse to break a stuck valve free. This “hammer blow” effect prevents false alarms and ensures operational readiness.
• Motor Overcurrent Protection: The control logic constantly monitors motor current. If the current exceeds safe thresholds due to a mechanical obstruction or voltage sag, the actuator cuts power immediately to prevent burnout.
• Over-Torque Protection: Users can set a specific torque limit via the menu. If the actuator encounters resistance exceeding this set point, it halts and alerts the user, safeguarding the valve stem and seat.

Control Methods

The BD250-C8 multi-turn electric actuator provides unmatched control flexibility. Beyond standard open/close, it offers:

• Two-Wire Control: For applications requiring “Signal-On/Valve-Open” or “Signal-On/Valve-Close” logic, this reduces cabling costs.
• Inching (Intermittent) Operation: The actuator can operate in a start/stop manner, effectively increasing the total stroke time. This is essential for preventing fluid hammer in pipelines or managing surge conditions.
• Fieldbus Redundancy: For critical processes, we offer redundant Profibus-DP modules. If one bus network fails, the actuator automatically switches to the secondary path to ensure uninterrupted communication.

Model and Type

• On-Off Type (BD-C8) multi-turn electric actuator: This model focuses on end-position reliability. It features high torque output and is best suited for applications where the valve remains open or closed for extended periods.
• Modulating Type (BDM-C8) multi-turn electric actuator: This model focuses on accuracy. It uses solid-state relays to handle the high frequency of starts and stops required by flow control loops, providing a long service life and high positioning precision.

  

Specifications

• Output Torque Range: 50 N.m to 3500 N.m (Up to 300,000 N.m with gearboxes).
• Output Speed: 12 rpm to 144 rpm (Various combinations available).
• Operating Current: Optimized for low inrush and running current to reduce upstream electrical component sizing.
• Input Signals: AC/DC 24V, AC 220V, Dry Contacts, 4-20 mA.
• Feedback Contacts: 4 programmable bistable relays (retain state during power loss), 1 programmable monostable relay, and 1 fault relay.
  

  BD250-C8 Three Phase
  Output Speed (rpm)	Rated Torque (N.m)	Motor Power (KW)	Locked Current (A)	Rated Current (A)	Weight (kg)
  24	2500	5	82.73	15	140
  36	2200	5	82.73	15
  48	1800	7	108	20
  72	1500	8	141.39	28
  96	1200	8	141.39	28
  144	1000	8	141.39	28

How does the split-body version (C8F) multi-turn electric actuator work in high-temperature areas?

The split body separates the sensitive electronics from the heat source. The actuator mechanism (gearbox and motor) remains on the valve, while the control unit can be mounted up to 10 meters away (or longer with a custom order) in a cooler, vibration-free location.