The WST I series is the most widely used solution for standard voltage adjustment. By changing the high-voltage winding turns at the terminal point, it stabilizes output voltage and ensures peak transmission efficiency. Its precision-machined copper contacts minimize power loss and provide long-term reliability in mineral or silicon oil environments.

Technical Principles & Notice
Voltage Regulation: Adjusts the high-voltage winding turns ratio to stabilize output voltage.
Loss Minimization: Optimized contact design reduces power losses. Since voltage loss is inversely proportional to the voltage level, our switches ensure peak transmission efficiency.
Compatibility: Fully compatible with Mineral Transformer Oil and Silicon Oil.

“Please select the corresponding Model No. (1-15) from the dropdown list according to the dimension table above.”
Technical Table
Frequently Asked Questions (FAQs)
Q: How do I choose between WST I and WST III?
A: WST I is for Terminal Point regulation, while WST III is for Neutral Point regulation. Check your transformer winding diagram before ordering.
Q: Why do WST II, IV, and V have two operating handles?
A: These are “Combination Types” (ZH2/ZH3). The dual handles are required to perform complex tasks like Y-Delta switching or Series-Parallel transitions.
Q: Can I operate the WST tap changer while the transformer is powered?
A: NO. This is an Off-Circuit device. Switching must only be performed when the transformer is completely de-energized.
Q: What is the significance of the “T” suffix in model numbers?
A: The “T” indicates a specialized design with modified dimensions or terminal points. Please contact us for specific drawings.
Q: What is the standard regulation step?
A: The standard regulation is 2.5% per position, allowing for precise voltage control across 3 to 9 steps.
Safety Operation (Mandatory)
This is an OFF-CIRCUIT device. Switching must ONLY be performed when the transformer is completely DE-ENERGIZED and isolated from the grid. Manual operation during energized states is strictly prohibited and will cause catastrophic equipment failure.
Important Procurement Notice
Please cross-check the Total Length (L) and Mounting Height (H) in the dimension table against your internal tank clearance.
Refer to the serial number (1-15/23) in the datasheet to select the exact model from the dropdown menu.











