How to distinguish between good and bad quality bearing heaters

Bearing heaters are an application of Faraday's principle. They primarily utilize a magnetic field to induce eddy currents within a conductor workpiece, causing it to heat up. Based on the principle of thermal expansion and contraction, a bearing is then mounted onto a shaft for heating.

The bearing heater industry has been developing for many years, but the market is now flooded with products of varying quality. This can be confusing for those unfamiliar with such equipment, as seemingly similar bearing heaters can have vastly different prices.

This article analyzes the bearing heater industry and the materials used in its main components, hoping to help readers make informed choices and avoid being scammed. If this article is helpful, please consider giving it a thumbs up.

First, let's introduce the components of a bearing heater. The core components of a power frequency bearing heater consist of silicon steel sheets and an induction coil.

1: Coil: Currently, most manufacturers use recycled copper coils, while some unscrupulous manufacturers use aluminum coils or copper-clad aluminum coils that have been partially filled. These materials are much cheaper than pure copper, but the resulting magnetic field strength is significantly weaker. Furthermore, it is not durable and cannot be used frequently, otherwise the coil will easily burn out.

2: Silicon Steel Sheets: Silicon steel sheets are mainly divided into cold-rolled silicon steel sheets and hot-rolled silicon steel sheets according to the manufacturing process. Cold-rolled silicon steel sheets have a higher magnetic saturation point, and begin to saturate at a magnetic flux density of 1.9T (19000Gs); the saturation point of hot-rolled silicon steel sheets is about 1.6T (16000Gs). Under the same magnetic flux density and frequency, cold-rolled silicon steel sheets have lower unit losses than hot-rolled silicon steel sheets. Cold-rolled silicon steel sheets are available in both non-oriented and oriented types. Oriented cold-rolled silicon steel sheets have obvious directionality, that is, good magnetic properties along the rolling direction, high saturation magnetic flux density, and low unit loss and unit excitation capacity. Currently, cold-rolled oriented silicon steel sheets are used in transformers. Hot-rolled silicon steel sheets are all non-oriented. Currently, the bearing heaters produced by Qingdao Weike Terui Automation Equipment Co., Ltd. all use cold-rolled oriented silicon steel sheets with a thickness of 0.35mm, which are among the better silicon steel sheets on the market. Small factories in Jiangsu mostly use recycled hot-rolled silicon steel sheets, which are quite inexpensive. However, their heating efficiency and durability are far inferior to those of cold-rolled silicon steel sheets. Some might say, "I bought a very cheap one, and it works fine." This is a misconception. Many people buy bearing heaters for maintenance purposes, typically using them only a few times a year, and heating only a few bearings each time, so they don't notice a significant difference in efficiency and product quality. If your bearings are large, require long heating times, or operate continuously, then the difference between the two will be very noticeable.