Introduction
The phase-breaking limit switch consists of a housing, moving contacts, fixed contacts, push rod, return spring and transmission mechanism, installed at the electric hoist drum end, with the push rod connected to the rope guide via a connecting rod. During normal hoisting, the rope guide moves left and right with the wire rope; when the hook rises to the limit position, the rope guide touches the push rod, pushing the moving contacts apart from the fixed contacts and cutting off the motor’s three-phase main power supply; similarly, when lowering to the limit position, it acts in reverse. The phase-breaking limit switch directly cuts off the power circuit, safer and more reliable than control-circuit limits, forcibly cutting power even if the contactor sticks. The contacts adopt silver-based alloy with good conductivity, arc resistance and long life; the housing adopts cast iron or cast aluminum with protection grade IP54. Widely compatible with various CD/MD wire rope electric hoists, it serves as the most basic terminal protection device for hoisting mechanisms.
Our Advantage
Direct main-circuit breaking for safety: Directly cuts off the motor’s three-phase main power supply (power circuit), not the control circuit; even if the contactor sticks or contacts weld, it forcibly cuts power, fundamentally eliminating over-hoisting accidents, with safety level far higher than control-circuit limits.
Dual-direction limit for comprehensive protection: Simultaneously provides both upper limit and lower limit protection—upper prevents over-hoisting and wire rope breakage, lower prevents over-lowering, rope tangling and hook falling—one device achieves full-stroke terminal protection for hoisting with comprehensive functions.
Simple structure with low cost: Consisting of simple mechanical parts such as contacts, push rod and spring, no electronic components, with extremely simple structure, easy manufacturing and low cost, serving as the most economical and practical terminal limit solution for electric hoists, with convenient maintenance and replacement.
4.Silver-based contacts with arc resistance and long life: Moving and fixed contacts adopt silver-based alloy materials such as silver cadmium oxide, with good conductivity, arc erosion resistance and weld resistance, mechanical life ≥1 million cycles, electrical life ≥100,000 cycles, maintaining reliable make-and-break even after long-term frequent operation.
Easy installation with strong adaptability: Fixed to the drum end via bolts, with push rod connected to the rope guide, no need to modify the hoist body, compatible with 0.5t~100t various CD/MD electric hoists, 4-pole/6-pole optional, convenient for both new installation and renovation, with extremely strong versatility.
Specification
| Parameter | 0.5~5t | 10~20t | 32~50t | 80~100t |
| Applicable Capacity | 0.5/1/2/3/5t | 10/16/20t | 32/50t | 80/100t |
| Applicable Motor Power | 0.8~7.5kW | 13~18.5kW | 22~30kW | 37~45kW |
| Poles | 4-pole | 4-pole / 6-pole | 6-pole | 6-pole |
| Rated Voltage | AC 380V | AC 380V | AC 380V | AC 380V |
| Rated Current | 10~20A | 30~40A | 50~60A | 80~100A |
| Control Directions | up+down | up+down | up+down | up+down |
| Trigger Stroke | 10~20mm | 15~30mm | 20~40mm | 30~50mm |
| Mechanical Life | ≥1M | ≥1M | ≥1M | ≥1M |
| Electrical Life | ≥ 100K | ≥ 100K | ≥ 100K | ≥ 100K |
| Contact Material | AgCdO | AgCdO | AgCdO | AgCdO |
| Housing Material | cast iron /cast aluminum | cast iron /cast aluminum | cast iron /cast aluminum | cast iron /cast aluminum |
| Protection Grade | IP54 | IP54 | IP54 | IP54 |
