400NM Dual Brake Secures Heavy Loads – Wheatstone Ex Servo Motor Delivers True Redundanc

A Single 200NM Brake Failure Could Drop a Multi-Tonne Cutting Arm in an Instant – Wheatstone Flameproof Servo Motors with Dual-Brake Redundancy Secure the Safety Baseline for Underground Heavy-Load Vertical Lifting

On underground coal mine intelligent excavation faces, bolter-miner cutting arms weigh several tonnes. When the cutting arm is in a vertical or steeply inclined position, a power failure or brake failure could send the heavy cutting head accelerating downward under gravity – resulting in equipment damage or casualties.

Brake-equipped flameproof servo motors are the critical solution to this problem. The braking torque of a single brake is typically only approximately 1.2 times the motor‘s rated torque. Faced with a multi-tonne cutting arm, this marginal braking torque offers virtually no safety margin. Industry standards require that the braking torque for vertical lifting axes must exceed 1.5 times the load torque. A single brake with only 1.2 times margin means every power outage is a potential life-or-death event.

A single brake can fail due to wear, sticking, or coil damage. In underground environments of high humidity, high dust, and frequent impact, brake wear accelerates far more rapidly than in surface equipment. If the brake fails, the motor‘s electromagnetic torque alone cannot hold a multi-tonne cutting arm – the consequences are catastrophic.

WHEATSTONE Dual-Brake Design: One Braking System, Two Independent Safeguards

WHEATSTONE offers custom dual-brake flameproof servo motors, integrating two independently controlled braking devices at the motor rear end. The two brakes can be driven by separate control signals, delivering true redundancy.

One Brake at 200NM, Dual Brakes at 400NM – Safety Margin from “Barely Enough” to “More Than Sufficient”

Each Wheatstone dual-brake flameproof servo motor delivers 200N·m static friction torque per brake. When both brakes engage simultaneously, total braking torque reaches 400N·m. This value far exceeds the 1.5× safety factor required by industry standards, providing ample safety margin for underground heavy-load vertical lifting.

200N·m × 2 = 400N·m total braking torque – sufficient to lock multi-tonne cutting arms, lifting platforms, and heavy-duty valves

Safety margin far exceeding industry requirements – from “may not hold” to “absolutely holds”

Dual brakes engaging simultaneously with true redundancy – one brake failure does not affect the other

Three Core Advantages of Dual-Brake Design

Advantage 1: True Redundancy – One Fails, the Other Still Holds

Two independent braking devices are installed in series or parallel. If either brake fails, the other still locks the load reliably. Control system monitoring and periodic self-checks on both brakes eliminate the fall risk caused by single-brake failure. This design complies with international safety standards including EN ISO 13849-1 for high-reliability vertical axes.

Advantage 2: Programmable Timing Control – Eliminating “Instant Drop on Start”

WHEATSTONE drives feature programmable brake control logic, allowing flexible configuration of “brake release delay” and “brake engage delay” parameters. On start-up, the motor energises and builds torque first, then releases the brake after a delay. On stop, the brake engages first, then motor excitation is cut after a delay. For heavy-load vertical lifting systems exceeding 10 tonnes, this timing control fundamentally eliminates the hazardous time window where “the brake has released but the motor has not yet built torque.”

Advantage 3: Independent Control and Status Monitoring – Catching Every Hidden Hazard

The two brakes are driven by separate control signals, enabling independent control and real-time status monitoring. The control system can perform periodic self-checks on both brakes to detect potential issues such as wear and sticking in advance. Brake power supply is isolated from the motor main circuit within the flameproof terminal box, ensuring that even under control system faults or unexpected power loss, heavy lifting platforms remain securely locked.

Typical Applications for Wheatstone Dual-Brake Flameproof Servo Motors

Bolter-miner cutting arm lifting: Multi-tonne cutting arms in vertical or steeply inclined positions require 400N·m braking torque from dual brakes to ensure no drop on power failure

Underground heavy lifting platforms: Vertical transport of tens of tonnes of materials and equipment – single-brake safety margin is insufficient; dual brakes provide double protection

Coal silo discharge gates: Fall protection for heavy gates under coal dust pressure

Flameproof gantry robot Z-axis: Vertical lifting axes carry extreme loads – industry standards require braking torque exceeding 1.5× load torque; dual-brake design meets and exceeds this requirement

When a multi-tonne bolter-miner cutting arm is securely locked by 400N·m of dual-brake torque at the instant of power failure; when an underground heavy lifting platform completes every vertical transport operation under dual-brake redundancy; when every Wheatstone dual-brake flameproof servo motor operates reliably for thousands of hours in high-humidity, high-dust underground environments – inside every heavy-load vertical system requiring zero fall risk, Wheatstone dual-brake flameproof servo motors are securing the final line of defence for underground heavy-load safety with 400N·m total braking torque and true redundant safety design.

Applicable Standards Reference

About Wheatstone

With more than 20 years of specialised experience in flameproof and special-purpose motors, Wheatstone offers a comprehensive portfolio including dual-brake flameproof servo motors, flameproof servo motors, high-temperature motors, deep-sea motors, and axial flux motors. The company is ISO 9001 and IATF 16949 certified, holding Ex d I Mb coal mine flameproof certification, Ex db IIB T4 Gb / Ex db IIC T4 Gb gas explosion protection certification, and Ex tb IIIC T130℃ Db dust ignition protection certification. Custom dual-brake flameproof servo motor solutions are available, with 200N·m static friction torque per brake and 400N·m total braking torque, suitable for bolter-miners, underground heavy lifting platforms, flameproof gantry robots, and other heavy-load vertical lifting applications.

For customised dual-brake flameproof servo motor solutions, please contact the Wheatstone technical team.