Potential Problems And Tightening Standards For Loose Bolts In Dry-type Transformers

If abnormal noise or increased vibration occurs during operation of the dry type step up transformer system, it often points to a hidden but fatal mechanical defect: loose fixing bolts. Long-term electromagnetic force and thermal expansion and contraction cycles can easily lead to connection failures in components such as clamps, core clamping screws, and fan supports. This micro-displacement not only alters the magnetic circuit structure but can also trigger partial discharge, directly threatening the integrity of the winding insulation system.

Vibration-Induced Chain Reaction of Mechanical Failures

Loosening is not an isolated event; it triggers a vicious cycle. When the core clamp bolts lose preload, the density of the silicon steel sheets decreases, amplifying the magnetostrictive effect and generating high-frequency noise. Continuous abnormal vibration will be transmitted to the low-voltage busbar connections, causing increased contact resistance, which can lead to overheating or even melting of the contacts. If the fan components become unbalanced due to loose bolts, the resulting additional mechanical stress will accelerate bearing wear, ultimately causing the cooling system to fail.

Standardized Torque Verification Process

To address such potential problems, maintenance work must abandon the traditional practice of tightening by feel and instead implement strict torque verification standards.

• Tool Selection: Always use a calibrated torque wrench. Never use an adjustable wrench for final tightening to prevent uneven force application.

• Value Comparison: Refer to the manufacturer's torque chart based on the bolt size (e.g., M10, M12) and strength grade, strictly controlling the torque within the specified range (Newton-meters (Nm)).

• Operational Details: When tightening, apply torque in stages using a diagonal, alternating sequence, and use two wrenches to prevent damage to insulation components from twisting at the bolt root.

Regularly conducting special inspections of the bolts on equipment dry type transformer supplier is a core element in maintaining the long-term stable operation of the equipment. The maintenance team must include fastener condition in the preventative testing checklist, using quantitative data rather than experience-based judgment to eliminate potential risks. Only by implementing standardized fastening processes can the structural rigidity and electrical safety of the dry type transformer types be guaranteed under complex operating conditions.