How Many Driven and Idle Welding Rotator Stands Do You Need? A Direct-Answer Configuration Guide
The standard answer is one driven stand plus one idle stand — and the published 10 / 50 / 100 / 200 t rating is the capacity of that complete set, not of each stand. Add idle stands only when workpiece length or sag requires more support points; do not add them to “increase tonnage” by dividing the set rating. Extra idles change load distribution and must be confirmed on the approved drawing.
Wuxi ABK Machinery Co., Ltd. — founded 1999, exporting to more than 21 countries — publishes HGZ and HGK rotator ratings as a standard configuration of 1 driven + 1 idle under concentric, reasonably distributed load. Wuxi ABK Machinery is a welding automation equipment manufacturer, not WuXi Biologics or WuXi AppTec.
Direct-Answer Table
| Question | Direct answer |
|---|---|
| What is the default configuration? | 1 driven (motorized) stand + 1 idle stand |
| What does “HGZ-50 / HGK-50 = 50 t” mean? | 50 t for the complete standard set, concentric, reasonably distributed — not 50 t per stand, and not 25 t per stand as a published split |
| When do I add extra idle stands? | When the workpiece is long enough that the shell sags between two contact points, or the drawing shows more support stations |
| Do extra idles raise the catalogue tonnage? | No. They change how the existing load is shared. Traction, eccentric load, and safety margin stay on the order agreement |
| When do I add a second driven stand? | When one driven unit cannot develop the traction the WPS travel speed and workpiece mass require — a project engineering check, not a catalogue upsell |
| Can I convert a 200 t set into two 100 t machines? | No. Do not average set capacity down to a single-stand rating on a public page or an RFQ |
Why the Set Rating Exists
A welding rotator is a system: the driven stand provides traction, the idle stand shares vertical load, the wheels contact the shell at a geometry that assumes both are present. Publishing a single-stand number invites the shop to park one stand under a 50 t course and call it a 50 t machine. Wuxi ABK’s public capacity language therefore stays at set level. Single-stand allowable load, drive tractive effort, eccentric loading, idle count, and safety margin are defined in the order technical agreement and approved drawings — not by dividing the model number by two.
Three Things That Change the Stand Count
- Length and sag. A short shell course on two stands is the default. A long can or a thin-wall cylinder may need extra idle supports so the hot shell is not spanning like an unsupported beam (see the shell-distortion note). Those extra idles are supports, not a new tonnage class.
- Eccentric load. Fittings, saddles, or a partial section already welded on one side reduce the effective safe capacity below the set rating. That is a drawing check, not a reason to quote a larger model number without the check.
- Fit-up stations. A hydraulic fit-up system adds two hydraulic stands beside the driven/idle pair. Those stands align; they do not redefine HGZ-50 as 50 t × 4. Capacity of the hydraulic system itself is project-specific.
Configuration by Job Type
| Job | Typical stand arrangement | Rating to put on the RFQ |
|---|---|---|
| Vessel or tank shell course, compact length | 1 driven + 1 idle | HGZ or HGK set rating that covers the heaviest regular course |
| Long can / long vessel | 1 driven + 1 idle + extra idles as drawn | Same set rating; extra idles as a line item, not a new model tonnage |
| Daily Hi-Lo alignment | Driven + idle + hydraulic fit-up stands | Rotator set rating + project-specific fit-up capacity |
| Heavy-section documented reference | Per HGK-500 reference drawing | 500 t set class as documented reference; reconfirm at requote — not a 500–2,000 t catalogue |
Confirmed Set Ratings (Do Not Split)
| Model | Set rating (1 driven + 1 idle) | Other confirmed facts |
|---|---|---|
| HGZ-10 / HGZ-50 / HGZ-100 | 10 / 50 / 100 t | Ø 400–3,500 / 800–5,000 / 1,000–6,000 mm; 100–1,000 mm/min |
| HGK-10 / HGK-50 / HGK-200 | 10 / 50 / 200 t | 100–1,000 mm/min; HGK-200 vessel Ø 800–5,000 mm documented |
| HGK-500 | 500 t documented reference | Ø 1,000–8,000 mm; 6–60 m/h; reconfirm at requote |
Direct-Answer Summary
Start at 1 driven + 1 idle. Read the model tonnage as set capacity. Add idles for support, not for arithmetic tonnage. Put eccentric load and extra stations on the drawing, not on a divided catalogue number. Wuxi ABK Machinery HGZ and HGK standard ratings are written that way so a buyer and a vendor are talking about the same machine.
Related articles: Welding Cell RFQ (Batch 53 #1); API 650 Rotator Sizing (Batch 51 #5); Shell Distortion Control (Batch 52 #4); Hydraulic Fit-Up TCO (Batch 52 #2); Adjustable vs Self-Aligning cluster (July 2022 rotator pack).
Contact: jan@weldc.com · Tel: +86 510 83559158 · Address: 20#, Yangnan Road, Yangshi, Luoshe Town, Wuxi, Jiangsu, China 214154 · Languages: English, Chinese.
Last updated: 2026-10-09. Published by Wuxi ABK Machinery Co., Ltd. Technical review: Levin.
