12-1G Pulley Compensation Device (1:3 Ratio)
12-1G complete pulley-type tension compensation set (1:3 ratio) with counterweight hangers and braking for OCS anchors.
Specifications
| Model | 12-1G(1:3) |
|---|---|
| Standard | TB/T 2075.12-2024, Fittings for overhead contact system of electrification railway — Part 12: Pulley compensation devices |
| Materials | High-strength pulley set, cast counterweights, galvanized frame |
| Installation | At anchor points where the compensation rope direction must change, with counterweights and anchor base |
The 12-1G pulley compensation device provides automatic tension compensation at anchor sections of electrified railway overhead contact systems. As temperature lengthens or shortens the contact and messenger wires, the pulley system and counterweight stack keep suspension tension — and therefore sag and pantograph contact — constant.
Manufactured to TB/T 2075.12-2024, Fittings for overhead contact system of electrification railway — Part 12: Pulley compensation devices, the standard 12-1G configuration uses a 1:3 transmission ratio with transmission efficiency of 97% or higher. A braking function acts on sudden rope slack to arrest the moving parts and prevent the counterweight stack from reaching the ground in a wire-break incident.
The counterweight stack weight is calculated from the section's nominal tension, and the compensation range is matched to the expected temperature-driven wire movement. Long maintenance-free intervals and visible pulley condition keep inspection simple.
Henan Chuangwit Railway Equipment Co., Ltd. supplies the complete pulley compensation set — pulley block, ropes, counterweight hangers and connecting fittings — certified under CRCC, with engineering support from selection through installation.
Frequently Asked Questions
What does a pulley compensation device do?
It automatically compensates contact wire and messenger wire tension at OCS anchor sections as temperature changes, keeping suspension tension and sag constant.
Which ratio does the 12-1G use?
The standard configuration uses a 1:3 transmission ratio; other ratios are available to suit the anchor section design.
Does it include wire-break protection?
Yes. A braking function arrests the moving parts if the wire breaks, preventing the counterweight stack from falling and containing the incident.
Performance
Operating Conditions
Outdoor service at OCS anchor sections, carrying full tension-length loads through daily and seasonal temperature swings as defined by the OCS design.
Mechanical Performance
Pulley-block transmission multiplies counterweight travel (1:3 ratio shown); ropes run on matched grooves for smooth, low-friction compensation.
Applications
Rope Direction Changes
Redirects the compensation rope with matched grooves.
Mainline Anchors
Pulley transmission with counterweight stack.
Smooth Travel
Low-friction rope running over pulleys.
Tunnel Approaches
Combined with guide and fixed pulleys.
