The influence of electrical parameters on INSOCOAT insulated bearings

The influence of electrical parameters INSOCOAT electrically insulated bearings have different performances in DC and AC applications. In DC applications, INSOCOAT bearings function as normal (pure ohm) resistors. The alumina coating is an insulator, so its ohmic resistance (R) is very important. The breakdown voltage of the standard coating is 3,000 VDC and the resistance is greater than 200 M, which makes INSOCOAT bearings with efficient insulation performance. In AC applications, especially when the inverter provides high frequency, the performance of the bearing is different. Electrical insulating coatings (such as INSOCOAT ceramic coatings) function as parallel resistors and capacitors. Therefore, impedance (Z) must also be considered, as described in Equation 1: Equation 1: The electrical impedance of a capacitor connected in parallel with an ohmic resistor. Equation 1 shows that the higher the frequency, the larger the term including the capacitance in the formula, and the lower the impedance. In this case, the electrical impedance depends on the ohmic resistance (R), capacitance (C) of the resistor and the frequency (f) of the applied voltage. The capacitance of INSOCOAT bearings (Formula 2) depends on the size of the coating surface area of u200bu200bthe bearing (A), the thickness of the insulating coating (s), the material of the coating itself (r) and the dielectric constant (0, a material constant) . Formula 2: Capacitance of parallel plate capacitor. In order to increase the impedance of the bearing, the capacitance of the coating should be as small as possible. In practice, this means that the inner ring coating will always have a higher impedance than the outer ring coating. The same is true for coating thickness. The electrical impedance of VL0246 is much larger than that of VL0241 (Figure 2). How to measure the electrical parameters of INSOCOAT bearings Effective ohmic resistance measurements can only be obtained under controlled environmental conditions, because the measurement results may be affected by many different factors, such as humidity, cleanliness, temperature and contact surfaces. Figure 1 and Figure 2 respectively introduce the measurement principle of INSOCOAT bearings with outer ring coating and inner ring coating, which are in line with the actual installation conditions. Therefore, the electrical parameters described in Table 1 are only valid under installation conditions, a dry and clean environment, and the relevant shaft and bearing housing dimensions that meet the requirements of the comprehensive catalog.