Seven Sheave 660 Series Stringing Block for Multi Bundle UHV
Conductor Pulling
The SHQ660A is the seven sheave member of the 660 Series frame. It
was developed for the multi bundle spans on 750kV and 1000kV lines,
where six or eight sub conductors have to run at the same time and
every sheave has to hold its own share of a 75KN pull. The outer
six wheels are MC nylon, the centre wheel is cast steel, and the
assembly sits on a forged 40Cr axle inside a reinforced galvanized
frame. Practical result: one block replaces a pair of three sheave
units on the crossarm, the bundle stays parallel, and the crew
makes one lift instead of two.
Model Data and Comparison
| Item No. | Model | Sheaves | Rated Load (kN) | Weight (kg) | Groove Configuration |
| 10130 | SHQ660A | 7 | 75 | 190 | Centre cast steel sheave, six MC nylon conductor sheaves |
| 10128 | SHWQN660 | 5 | 60 | 110 | Five MC nylon sheaves |
| 10127 | SHSQN660 | 3 | 40 | 70 | Three MC nylon sheaves |
All three share the 660mm sheave diameter, so groove radius, hanger
hardware and crossarm spacing stay common across a fleet. Load
figures are per block with conductors seated in the grooves.
Engineering Behind the Seven Sheave Layout
Balanced bundle geometry: seven grooves at 660mm diameter keep sub conductor spacing close
to the design spacing of the bundle, which limits conductor
oscillation in the span and helps the final sagging match the
stringing calculation.
Load shared on a forged axle: the 75KN rated load is carried by a 40Cr forged axle rather than a
tube, with the frame gusseted at the axle seats. Under proof load
the frame shows no permanent set at the hanger eye.
Sealed rolling bearings: double sealed spherical roller bearings take both radial and small
axial misalignment, so the wheels keep turning even when the block
hangs slightly out of plumb on an angle structure.
Mixed wheel materials by design: MC nylon wheels protect the aluminium strands, while the cast
steel centre wheel handles the wear from spacers, running boards
and the occasional steel rope lead.
Positive conductor retention: each groove is closed by a keeper with a locking pin, so a slack
conductor cannot lift out of the sheave when tension is released
during changeovers.
Selection Guidance
A 1000kV eight bundle span normally uses the SHQ660A with a pair of
matching three sheave units; a six bundle line can run on the seven
sheave block alone plus one single sheave block at the lead
position. Match groove radius to the sub conductor diameter, keep
the first block at least ten times the sheave diameter behind the
tensioner, and confirm hanger bolt diameter against the crossarm
drawing before ordering. If the site has long pulls with high
tension, we recommend the seven sheave unit even on six bundle
lines for the extra safety margin.
Quality Control and Inspection
Each SHQ660A is assembled from inspected castings, forged axles and
nylon blanks. The axle is dimensionally checked and dye penetrant
inspected before assembly, the frame is checked for hanger eye
alignment, and the finished block is proof loaded and the sheaves
spun under load to confirm bearing seating. Blocks ship with a
nameplate showing model, rated load and serial number, plus an
inspection sheet; a 1.5 times rated load certificate and third
party inspection reports can be provided against the order drawing.
Packing, Handling and Service
At 190kg the unit is packed in a reinforced plywood case with
lifting points marked, and the sheave faces are protected against
impact in transit. Stock units move in 3 to 7 days, with monthly
capacity around 300 pieces. Spare sheaves, bearings, axles and
keeper pins are held as service parts, so a worn wheel can be
swapped on site instead of replacing the whole block.
Frequently Asked Questions
Can the seven sheave block be supplied with all cast steel wheels?
Yes, a steel wheel build is available for steel rope and mixed
duty, on request against the order drawing.
Is a custom groove radius possible? Groove radius, marking language
and hanger dimensions can be made to the buyer drawing for orders
above the standard MOQ.
What is the service interval? Bearings are sealed for life; the
sheaves, keeper pins and hanger eye should be inspected before each
project and after any overload event.
