ED301/6Ex Series Explosion-Protected Electro-Hydraulic Thruster

The ED301/6Ex series explosion-proof electro-hydraulic thruster is a compact integrated drive device combining motor, centrifugal pump and oil cylinder, designed for driving explosion-proof brakes (e.g., DYW series drum brakes) in hazardous areas. It meets the explosion-proof requirements of GB3836.2-2000 and IEC standards, with explosion-proof markings Exd IIB T4 Gb/Ex tD A21 IP65 T130℃, suitable for IIA/IIB flammable gas zones and combustible dust zones (T1-T4 temperature classes), widely used in mining, petrochemical, and port industries.

Core Technical Specifications

Parameter	Standard Value	Notes
Rated Thrust	3000 N	Stable output under explosion-proof enclosure
Rated Stroke	60 mm	External stroke limitation available
Motor Power	550 W	3-phase AC, insulation class F
Power Supply	380V/660V/1140V, 50Hz/60Hz	Compatible with hazardous area power grids
Explosion-Proof Marking	Exd IIB T4 Gb/Ex tD A21 IP65 T130℃	Dual protection for gas and dust environments
Working Temperature	-20℃ to +40℃	Standard range; expandable with heating kit
Protection Class	IP65	Dustproof and waterproof for harsh industrial conditions
Installation Angle	0°–180°	Balance air chamber enables flexible mounting
Weight	~45 kg	Compact design for easy integration with brakes

Key Structural Features

Explosion-Proof Integrated Design

Flameproof enclosure with precision-machined flame paths to contain internal sparks; all electrical components (motor, terminals, limit switches) are explosion-proof certified.

Cable entry uses sealed explosion-proof joints, and the motor junction box is fully sealed to prevent gas/dust ingress, maintaining IP65 protection.

Electro-Hydraulic Drive Principle

When powered on, the motor drives the centrifugal pump to generate hydraulic pressure, pushing the piston rod to extend (release brake). When power is cut off, the return spring retracts the rod (applies brake), ensuring fail-safe operation.

Hydraulic operation ensures smooth, impact-free motion with high switching frequency (up to 2000 cycles/hour in S3 mode).

Durable & Low-Maintenance

Motor adopts non-immersed design with high insulation grade; all seals and bearings use international brand components for long service life.

Fasteners are stainless steel, and the cylinder surface is anti-corrosion coated, suitable for humid and corrosive environments.

Working Principle

Brake Release (Power-On): The motor drives the hydraulic pump to build pressure, pushing the piston rod to extend against spring force, separating brake shoes from the drum.

Brake Application (Power-Off): Hydraulic pressure drops, and the return spring pulls the rod back, clamping the brake shoes to the drum for emergency braking.

Interlock Protection: Equipped with explosion-proof limit switches to send release/closure signals to the control system, preventing equipment startup before full brake release.

Installation & Maintenance Guidelines

Installation Requirements

Mounting angle: 0°–180° (ensure balance air chamber is properly vented).

Use explosion-proof cables and certified connectors; tighten flame path bolts to specified torque (30–35 N·m).

Ensure proper alignment with the brake to avoid lateral forces on the piston rod.

Maintenance Schedule (Hazardous Area Compliance)

Cycle	Core Tasks	Details & Standards
Daily	Visual Inspection	Check enclosure integrity, cable connections, and oil level (via sight glass).
Monthly	Lubrication & Leak Check	Apply explosion-proof grease to hinge points; inspect hydraulic system for leaks.
Quarterly	Thruster Performance Test	Test thrust output (≥2700 N) and stroke accuracy (±1 mm); check motor insulation (≥1 MΩ).
Annually	Comprehensive Overhaul	Replace hydraulic oil (ISO VG46), inspect flame path gaps (≤0.15 mm), and verify explosion-proof certificate validity.

Hazardous Area Precautions

Maintenance must be performed after power cut, lockout-tagout, and gas concentration confirmation.

Use only explosion-proof tools to avoid sparks; do not modify the thruster structure (e.g., drilling holes in the enclosure).

Common Faults & Solutions

Fault Phenomenon	Possible Causes	Solutions
Piston rod does not extend	Oil shortage, motor failure, or blocked hydraulic circuit	Replenish ISO VG46 oil; test motor windings; clean hydraulic filter.
Insufficient thrust	Leaking seals, worn piston, or weak return spring	Replace seals; inspect piston for wear; replace spring set.
Explosion-proof enclosure overheating	Poor ventilation, motor overload, or contaminated oil	Ensure proper ventilation; reduce load; replace hydraulic oil.
Limit switch signal failure	Loose terminals, damaged switch, or cable short	Tighten terminals; replace explosion-proof switch; repair cable.

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This thruster is a critical component for explosion-proof braking systems, ensuring safe operation in hazardous environments. Regular maintenance and strict adherence to explosion-proof guidelines are essential for reliable performance.

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