YW-K400/E121 Normally-Open Electro-Hydraulic Drum Brake

YW-K400/E121 Normally-Open Electro-Hydraulic Drum Brake

The YW-K400/E121 is a specialized Normally-Open (Fail-to-Safe) Electro-Hydraulic Drum Brake. Unlike standard "Normally-Closed" brakes which stop a machine when power is lost, this unit is designed to hold a machine stationary when powered and release it (allowing it to move) when power is cut or in the event of a power failure.

The "K" in the model designation typically stands for "Kai" (Open) in Chinese industrial nomenclature, indicating the Normally-Open function.

The model number breakdown is as follows:

YW: The series designation for Electro-Hydraulic Drum Brakes.

K: Indicates Normally-Open configuration (Electrically Released, Spring Applied).

400: The Brake Wheel Diameter of 400 mm.

E121: The specific Thruster Model (equivalent to Ed121/6). The "121" indicates a high-thrust frame size (approx. 1250N), suitable for large 400mm brakes.

💡 Key Features & Characteristics

Normally-Open Operation (Safety Release):

Holding (Powered): When the thruster is energized, it pushes the brake shoes against the drum, creating friction to hold the load or keep the machine stopped.

Releasing (Unpowered): When power is cut (or in an emergency), the springs retract the shoes, releasing the brake and allowing the machinery to move freely (e.g., allowing a crane to lower a load via gravity in a controlled manner or freeing a stuck conveyor).

Application Logic: This is often used as a "safety release" or "holding brake" rather than a service brake.

High-Capacity Thruster (E121 / Ed121):

Thrust: The E121 thruster generates a rated thrust of approximately 1250 N (125 kgf).

Stroke: Typically 60 mm (standard for the 121 frame size).

Design: It is an integrated electro-hydraulic unit designed for high force output to clamp the large 400mm drum effectively.

Interlocking Equalizing Mechanism:
The YW series features a mechanical linkage that ensures both brake shoes retract and apply equally. This prevents uneven wear and ensures the brake releases symmetrically.

Visual Torque Adjustment:
The main compression spring is housed in a square tube with a graduated scale, allowing operators to easily read and adjust the holding torque (clamping force).

Maintenance-Free Linkage:
The main pivot points are equipped with self-lubricating bearings, eliminating the need for manual greasing.

🏭 Typical Applications

The YW-K400/E121 is used in specific safety-critical applications where a machine must be held by the brake and released to move:

Cranes & Hoists: Used as a holding brake on the high-speed shaft to prevent the motor from drifting when stopped, but releasing instantly to allow lowering.

Conveyors: Used as a "backstop" or holding device to prevent reverse movement on inclined conveyors when powered down.

Wind Turbines: Often used as a rotor lock or parking brake that releases to allow rotation.

Emergency Release Systems: In machinery where a "fail-safe" state requires the brake to be disengaged (open) to prevent damage or allow manual movement.

📋 General Technical Specifications

表格

Note: The Normally-Open configuration is the inverse of the standard YWZ series (which is Normally-Closed). Ensure your control system is wired correctly: this brake consumes power to hold/brake and releases when power is off. Installing a Normally-Open brake in a Normally-Closed application (or vice versa) can lead to dangerous safety failures.

Hot Tags: yw-k400/e121 normally-open electro-hydraulic drum brake, China, manufacturers, supplier, factory, customized