In overhead crane operations, exceeding the Safe Working Load (SWL) can cause catastrophic mechanical failure, wire rope breakage, motor burnout, and structural collapse. ZOKECRANE Overhead Crane Overload Limiters (Overload Protection Devices) are critical electronic safety systems designed to continuously monitor lifting loads in real-time, automatically trigger audible alarms, and cut off hoisting motor power instantly when safe capacity thresholds are exceeded.
Overview of ZOKECRANE Crane Overload Protection Systems
Manufactured by Henan Zoke Crane Co., Ltd., ZOKECRANE overload protection devices combine high-precision load cell sensors (pressure, tension, or pin-type) with intelligent microcomputer digital control units. Engineered for seamless integration onto wire rope electric hoists, double girder trolley winches, and heavy-duty EOT cranes, our overload limiters conform strictly to international safety standards, offering real-time LED load display, dual-relay contact cut-offs, and exceptional resistance to electromagnetic interference.
Key Technical Specifications & Parameters
| Technical Parameter |
Overload Limiter Specification |
| Equipment Type |
Electronic Overhead Crane Overload Limiter / Cut-off Device |
| Applicable Crane Capacity |
1 Ton to 500+ Tons (Custom sensor ranges available) |
| System Measurement Accuracy |
≤ ±1% to ±3% F.S. (Full Scale) |
| Alarm & Cut-Off Points |
90% SWL (Warning alarm), 100% SWL (Audible/Visual alarm), 105%–110% SWL (Instant motor power cut-off) |
| Sensor Types Available |
Side-clamp load cell, load pin sensor, plate pressure sensor, tension load cell |
| Operating Voltage |
AC 220V / 380V / 440V (50Hz/60Hz, customizable) |
| Display & Control Unit |
High-brightness LED digital load readout display with relay outputs |
| Enclosure Protection Class |
IP65 Waterproof & Dustproof Control Box |
| Operating Temperature |
-20°C to +70°C (High-temperature foundry options available) |
| Certifications & Standards |
ISO 9001 Quality System, CE Certified, SGS Verified |
Core Product Advantages & Safety Features
- Instant Automatic Power Cut-off: When the lifted weight exceeds 105%–110% of the rated capacity, the internal heavy-duty relay cuts off the motor’s upward hoisting circuit, preventing dangerous lifting while allowing safe lowering.
- Dual Alarm Warning Mechanism: Provides early acoustic and optical warnings at 90% SWL to alert crane operators before an actual overload occurs.
- High-Precision Load Cell Technology: Utilizes strain-gauge alloy steel load sensors with strong anti-vibration performance and thermal stability.
- Anti-Dynamic Peak Filter: Intelligent microchip algorithms filter out sudden dynamic peak forces during initial acceleration, preventing false tripping during smooth lifts.
Industrial Applications of Crane Overload Limiters
ZOKECRANE crane overload protection systems are mandatory safety devices installed across diverse lifting equipment and industrial sectors worldwide:
1. Overhead & Gantry Cranes
Protects single girder hoists, double girder trolleys, and gantry cranes from illegal or accidental structural overloading in manufacturing workshops.
2. Metallurgical & Foundry Steel Mills
Heat-resistant load limiter models installed on ladle cranes and scrap handling cranes to prevent overload hazards under high-temperature radiant heat.
3. Port & Container Terminals
Accurate load monitoring for rail-mounted gantry cranes (RMG), rubber-tired gantry cranes (RTG), and heavy yard winches.
4. Warehousing & Logistics Centers
Prevents overloading during heavy palletized goods loading, die/mold lifting, and automated crane hoist operations.
Frequently Asked Questions (Product FAQs)
How does a crane overload limiter protect the hoisting motor and crane structure?
The system measures the weight via a load cell sensor. If the load exceeds safe pre-set thresholds, the digital controller opens its output relay contact, which opens the motor contactor coil circuit. This halts the upward motion instantly, protecting the motor from thermal overload and preventing structural stress failure.
What is the difference between a side-clamp sensor and a load pin sensor?
A Side-Clamp Sensor clamps directly onto the fixed end of an existing wire rope without dismantling the crane, making it perfect for quick retrofits. A Load Pin Sensor replaces the original equalizing sheave axle pin, offering higher measurement precision (±1%) for heavy-duty industrial cranes.
Can the crane lower the load after an overload trip occurs?
Yes. The overload limiter strictly cuts off the upward hoisting power circuit while leaving the downward lowering circuit fully operational, allowing the operator to safely lower the overloaded object back to the ground.
Does ZOKECRANE provide overload limiters for outdoor or high-temperature environments?
Yes. Our control boxes feature IP65/IP66 weather-sealed enclosures. For metallurgical applications, we supply high-temperature sensors and heat-shielded cabling capable of operating near high thermal radiation sources.
Export & Logistics FAQs for International Buyers
Which international markets does ZOKECRANE export overload limiters to?
ZOKECRANE crane safety components and lifting equipment are exported globally, supplying crane builders and industrial maintenance teams in Russia, Uzbekistan, the Philippines, Bangladesh, Australia, Qatar, Tanzania, Singapore, Saudi Arabia, Brazil, Nigeria, and many other countries worldwide.
How are overload limiters and sensors packaged for international shipping?
Electronic display units, sensors, and connecting cables are wrapped in anti-static moisture-proof film, cushioned with shock-absorbing foam inserts, and packed in heavy-duty export-standard fumigated wooden cases or reinforced cartons.
What quality and safety certifications accompany ZOKECRANE overload limiters?
Every ZOKECRANE overload protection system is manufactured under ISO 9001 Quality Management System compliance, carries European CE safety certification, and is backed by factory calibration sheets and SGS inspection reports upon request.
What commercial shipping terms and lead times do you offer for overload limiters?
We support standard international trading terms including FOB, CIF, CFR, DDU, and DDP. Standard overload limiter models are kept in stock with fast lead times of 5 to 10 business days; custom sensor configurations or bulk orders take 15 to 20 business days.
Does ZOKECRANE provide wiring diagrams and technical support for installation?
Yes. Every unit is shipped with clear electrical wiring schematics, calibration manuals, and step-by-step installation guides. Additionally, our technical support team provides 24/7 remote video assistance to guide your site electricians through sensor mounting, electrical wiring, and weight calibration.
