Description
Quarter-turn High Torque Electric Actuator Overview
The quarter-turn high torque electric actuator BJ/BJM101-IIC series from Bonray prioritizes operational safety and equipment protection. Our factory designed this actuator to operate reliably in hazardous environments (gas and dust) and to protect itself and your valve from damage under fault conditions. You can deploy it in Zone 1, 2 gas explosive atmospheres (IIA, IIB, IIC groups, T1-T4 temperature class) and Zone 21, 22 dust explosive atmospheres (IIIA, IIIB, IIIC, T130°C). We achieve this through flameproof enclosures (Ex db), thermal management, and comprehensive electronic protections.
Even in non-hazardous areas, the actuator includes phase loss detection, motor thermal overload, instant reverse delay, torque limiting, and valve stuck release logic. This overview explains each safety feature, how to correctly install the actuator in hazardous areas, and how our factory tests each protection function. We also cover the double-seal IP68 design that keeps water and dust out even when the terminal cover is removed for wiring.
What certifications does the explosion-proof version hold?
Our factory certifies the quarter-turn high torque electric actuator to Chinese standards GB/T3836.1-2021 and GB/T3836.2-2021. Gas explosion-proof marking: Ex db IIC T4 Gb. Dust explosion-proof marking: Ex tb IIIC T130°C Db. We can also provide IECEx or ATEX certification on request (additional lead time). The certificate number is printed on the nameplate.
Quarter-turn High Torque Electric Actuator Features
Flameproof Construction (Ex db IIC T4 Gb)
Our factory machines the enclosure with flameproof joints:
Flameproof spigot joint: gap ≤0.15 mm, length ≥25 mm.
Flameproof shaft joint: uses labyrinth + O-ring.
Flameproof bonding: for cable entry threads.
All materials (aluminum alloy for housing, stainless steel for shafts) are non-sparking. The actuator contains no internal ignition sources. The flameproof design contains any internal explosion and cools escaping gases to below ignition temperature.
Field Application Diagram of BJBJM-IIC
Dust Ignition Protection (Ex tb IIIC T130°C Db)
For dust hazardous areas, the enclosure limits surface temperature to 130°C (max) under all operating conditions. The double-seal prevents dust ingress (IP6X). Our factory applies a special anti-static coating to the housing to prevent dust accumulation from generating static charges.
Motor Thermal Protection
We embed a Klixon-type thermal protector directly in the stator windings. This sensor responds to actual winding temperature, not just case temperature. Trip point: 130°C ±5°C. The actuator displays “Motor Overheat” and disables operation until temperature drops below 90°C. Our factory tests each motor’s thermal curve on a dyno.
Electronic Torque Limiting
The absolute encoding torque sensor provides real-time measurement. You set separate limits for open and close directions (30% to 100% of rated torque). When the measured torque exceeds the limit, the actuator stops and the alarm relay toggles. The LCD shows “Torque Trip – Open” or “Torque Trip – Close.” Our factory pre-sets limits to 100% but recommends lowering to 80% for new valves.
Phase Sequence Auto-Correction
Instead of requiring you to swap wires, the actuator detects L1, L2, L3 order and energizes the appropriate contactor. This works for both forward and reverse. However, phase loss protection remains active. Our factory uses a rotating field simulator to verify auto-correction.
Instant Reverse Delay
Prevents full mechanical reversal without stopping. The quarter-turn high torque electric actuator builds in a 200 ms dead time after a stop command before accepting a command in the opposite direction. This extends gear life. Our factory endurance test shows 2 million cycles without gear wear.
Valve Stuck Release Logic
Two scenarios:
From closed position moving to open: torque trip disabled for first 5-8 seconds.
From any position: torque trip disabled for first 0.2-0.3 seconds.
After these periods, if torque still exceeds limit, the actuator stops and reports “Valve Stuck.” Our factory recommends using this logic only for valves with occasional stiction (e.g., butterfly valves with seat rubber swelling).
Power Fail-Safe (Mechanical Self-Locking)
The planetary gear train has a self-locking ratio. When power is removed, the valve position remains fixed even under line pressure up to the rated torque. No brake or holding relay is needed. Our factory tested self-locking with 150% of rated back-driving torque.
Double-Seal IP68 Terminal Box
The outer cover uses a silicone O-ring. The inner seal plate (removable for wiring) uses a flat gasket. Even with outer cover removed, the inner seal maintains IP54 protection. When both covers are installed, the assembly passes 48-hour submersion at 2 meters (GB4208-2017). Our factory randomly samples one unit per batch for this test.
Data Sheet
| BJ101-IIC | Output speed (rpm) | Rated torque (N.m) | Motor power (W) | Rated current (A) | Locked-rotor current (A) | Number of manual turns (n) | Weight (kg) |
| Three phase | 1 | 1000 | 200 | 1.9 | 3.4 | 20.25 | 30 |