ASTM D6786 Standard Test Method for Particle Count in Mineral Insulating Oil Using Automatic Optical Particle Counters
ASTM D6786用自动光学粒子计数器测定矿质绝缘油中粒子数的标准试验方法
Particles in insulating oil can have a detrimental effect on the dielectric properties of the fluid, depending on the size, concentration, and nature of the particles. The source of these particles can be external contaminants, oil degradation by-products, or internal materials such as metals, carbon, or cellulose fibers.
Particle counts provide a general degree of contamination level and may be useful in accessing the condition of specific types of electrical equipment. Particle counts can also be used to determine filtering effectiveness when processing oil.
If more specific knowledge of the nature of the particles is needed, other tests such as metals analysis or fiber identification and counting must be performed.
1. Scope
1.1 This test method covers the determination of particle concentration and particle size distribution in mineral insulating oil. It is suitable for testing oils having a viscosity of 6 to 20 cSt at 40°C. The test method is specific to liquid automatic particle analyzers that use the light extinction principle.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately)
ASTM Standards
D923 Practices for Sampling Electrical Insulating Liquids
ISO Standards
11171:1999 Hydraulic Fluid Power--Calibration of Automatic Particle Counters for Liquids
Index Terms
optical particle counter; particle count; particulate contamination; Automatic particle counters; Mineral insulating oil; Optical particle counters; Particle counters/counting;