Electrical equipment overheating is usually due to the Joule heat (\( I^2R \)) generated when current passes through conductors exceeding the normal heat dissipation capacity of the equipment, or due to abnormal conditions causing a sharp increase in heat. The following are common causes of electrical equipment overheating:
1. Resistance increase (poor contact)
Due to loose connections, oxidation or corrosion, the contact resistance increases sharply.
Loose connection: Loose screws, inadequate welding.
Contact aging: The contacts of switches, relays, and contactors become uneven or oxidized due to arc burn.
Internal strand breakage: Partial breakage within the wire, resulting in a reduction of the actual current-carrying cross-section.
2.Cooling system failure
For equipment with fans or oil cooling, such as transformers and large frequency converters, if the cooling fan stops rotating or the oil passage is blocked, the heat cannot be discharged.
3.Insulation Damage and Leakage
Inter-turn short circuit: The insulation layer inside the motor or transformer coil is damaged, causing a short circuit between adjacent coils. This results in a reduction of the number of coil turns, generating a huge circulating current and causing local high temperatures.
Phase-to-phase short circuit or ground short circuit: A huge short-circuit current will generate extremely high heat in a very short period of time, burning the equipment.
4.Harmonic Current
Non-linear Load: When a large number of equipment such as frequency converters, rectifiers, and switching power supplies are used, high-order harmonics will be generated. When the harmonic current flows through the conductor, due to the skin effect, additional losses will occur, causing abnormal heating of the equipment (especially transformers and neutral lines).
5.Improper design or selection
Insufficient capacity margin: During the design process, no consideration was given to future capacity expansion or startup surge current.
Low-quality materials: Insufficiently sized wires were used or conductive components made of non-pure copper/aluminum materials were employed.
6.Core component failure
Bearings wear: The rotating part of the motor rubs against the stator.
Capacitor aging: The internal dielectric loss of the filtering or compensation capacitors increases, resulting in overheating.
vTZ-12 vacuum circuit breaker
VTZ-12 vacuum circuit breaker (special model of Tongzhong Electrical Co., Ltd.) is an indoor switchgear for rated voltage 12kV, AC 50/60Hz. It adopts a modular operating mechanism and is suitable for various industrial and mining enterprises, as well as power grid equipment. It can be used as a handcart unit for use with KYN28A-12 switchgear, or as a fixed unit with relevant mechanical interlocking, making it suitable for XGN2 and other fixed cabinets.
Shaanxi West Power Tongzhong Electrical Co., Ltd.
Shaanxi West Power Tongzhong Electrical Co., Ltd. is a leading manufacturer with over 20 years of experience, specializing in high quality 7 to 40.5kV vacuum circuit breakers, switchgears, and a wide range of electrical products. Our advanced manufacturing process ensures reliable, durable solutions, especially our VTZ series vacuum circuit breakers, which are maintenance-free for up to 20 years. With a team of expert technicians, we excel in R&D, manufacturing, and after-sales service for both high and low voltage equipment, delivering excellence at every stage.
Contact us
Contact: Ms.Grace Liu (Director of Sales Department)
Tel: +86 917 3661109 Fax: +86 917 6739416
Mobile: +86 18091765882(WhatsApp/Wechat/facebook )
Website:https://www.xdtzelectrical.com
Add: Nanpo Village, Chencang Avenue Jintai District Baoji City, Shaanxi Province, China.
