Endurance E-3120 & E-4660 Spring Tubes Upgrade
A key part of the safety system on the Endurance E Series turbines is the blade spring tubes.
This is an essential part of the mechanism that pitches the blades to aerodynamically restrict rotor speed in the event of a brake failure.
DC21 are pleased to offer the Serenity Wind spring tube upgrade to all E-3120 and E-4660 models.
Endurance Wind Turbine E-Series Spring Tube Problems
No matter which version of the E-Series turbine you own, the original Endurance spring tubes are vulnerable to wear and failure, which can cause catastrophic blade damage.
Springs are also known to buckle during operation, resulting in loud noises, bangs, and rattles, which may disturb your neighbours.
Buckled springs could also compromise spring tube function if there is an overspeed.
Repeated buckling (blade knock) can lead to premature spring failure and may cause significant damage to the turbine components.
Superior Quality, UK Designed, Spring Tube Upgrade Installed by DC21
The Blade Spring Tube Upgrade (BSTU) is UK-designed and manufactured by Serenity Wind to overcome the failings of the original Endurance design.
With almost 100 sets fitted since 2017 accumulating over 1,000,000 service hours, including several winters, Serenity Wind BSTUs are constructed using only quality materials and components sourced from UK suppliers.
They are exclusively available for installation by DC21 Group.
The BSTU is a high-quality engineered item and comes with a 5-year return-to-factory limited warranty.
Blade Spring Tube Upgrade – Design Deep Dive
As shown in the illustration below, the SW-BSTU has a host of new features, designed to overcome the original spring tube flaws.
These Features Include:
- Spring Placement: The spring is trapped between the 45mm diameter chrome steel rod and the tube, so it cannot knock. In the E3120 RR and E4660 versions, nylon spacers keep the spring constrained and central.
- Waterproofing: Water is kept out by heavy-duty glands with seals and wear bands.
- Shock Absorption: Fully captive rubber buffer washers absorb shock during rotor overspeed, safeguarding other turbine components from unexpected, high-force impacts (shock loads) during startup, shutdown, or sudden gusts of wind.
- Upgrade Feature: The blade spring tube upgrade features an all-new rod end bearing housing, threaded onto the rod and secured with four locking screws.
- Protection System: A cover plate system has been developed with precision machining to ensure grease retention and water exclusion.
- Parts Reuse: No Endurance original parts are re-used.
- Seal Quality: Heavy-duty oil seal—more rugged than previous seal arrangements not present on OEM spring tubes.
- Design Improvement: The cover plate system has a tapered throat to simplify blade pin insertion and assist correct pin alignment.
- Maintenance Ease: All removable head components are secured with circlips for ease of maintenance.
- Long Life Bushes: Phosphor bronze or aluminium bronze (4660) shell bushes are used for long life.
- Bearings: The shell bushes are encased in a replaceable, press-fitted SKF hardened steel bearing shell, ensuring that inaccuracies and wear in adjacent components can be accommodated without side-loading the bushes.
New Endurance Wind Turbine E-Series Spring Tube Upgrade Benefits
Additional benefits from upgrading your E-Series spring tube include:
| Design Feature | Benefit |
|---|---|
| Spherical bearing | Prevents fatigue loads from transferring to the rod |
| Spring tension is calibrated specifically and accurately to the blade weight and centre of gravity | Less “fidgeting” during operation results in reduced wear and tear on other components
Preventing partial spring tube deployment in high winds can improve the power curve |
| Designed to prevent springs from buckling | Silent in operation
Ensures the spring tube deploys when demand arises |
| Rod is 45mm dia vs 24mm dia for the EWP design | More durable component |
| Sprung components are fully contained | Cannot damage the blade in the event of rod failure |
These spring tubes come with a 5-year return-to-factory limited warranty.
Thinking of Upgrading Your Endurance E-3120 / E-4660 Spring Tube?
Designed and manufactured in the UK by Serenity Wind, exclusively available for installation on your E-Series by DC21 Operations Ltd, contact us today to discuss your options.
E-4660 Products, Upgrades & Repairs
Spring tubes
DC21 are pleased to offer the Serenity Wind spring tube upgrade with all E-3120 and E-4660 models. These spring tubes come with a 5 year insurance backed limited warranty.
E-4660 Flex Coupling Upgrade
An upgraded coupling that is designed to prevent secondary damage in the event of flex plate failure.