The drop test tops out. IEC 60112 discriminates between poor, moderate and good tracking resistance for indoor equipment under moist conditions, and for that job it works. But it runs at hundreds of volts on 20 mm specimens for under an hour, and its own scope says the results do not qualify a material for outdoor service. Outdoor… Read More: IEC 60587 Inclined Plane Test: Tracking and Erosion »
CTI tells you what a material can do. PTI tells you whether the part in front of you still does it. The two come out of the same machine, run the same drops of the same electrolyte across the same platinum electrodes. The difference is the question. CTI hunts for a ceiling. The proof tracking index checks a… Read More: Proof Tracking Index (PTI): IEC 60112 Acceptance Test »
Insulating material does not have to break down through its bulk to fail. It can fail across its face. A thin film of dirty water, a few hundred volts, and enough time will burn a conductive path into a plastic surface that measured hundreds of megohms when it was clean. That path is called a track. IEC 60112… Read More: Comparative Tracking Index (CTI): IEC 60112 Test Method Explained »
Two conductive parts at different potentials need to be kept apart. You can measure that separation two ways: straight through the air between them, or along the surface of the insulation that connects them. Those are two different numbers, set by two different sets of rules, and a design has to pass both. Clearance is the air gap.… Read More: Clearance and Creepage Distance: How They Differ and What Sets… »
IEC 61238-1 is the standard that qualifies compression and mechanical connectors for power cables (up to 30 kV, Um = 36 kV). It doesn’t measure a connector once — it ages one through 1,000 heat cycles and checks two things the whole way: that its resistance stays stable, and that it never runs hotter than the cable conductor… Read More: Cable Connector Testing: The IEC 61238-1 Heat Cycle Test »
The standard behind the contact resistance test on high-voltage switchgear and circuit breakers is IEC 62271-1. It doesn’t use the phrase “contact resistance” — it calls the test “measurement of the resistance of the main circuit.” The method is a DC measurement across the contacts, taken as the average of three readings, at a test current of at… Read More: Contact Resistance Test: The IEC 62271-1 Standard »
The standards don’t change when you move from medium to high voltage. IEC 62271-1 and IEC 62271-100 cover every AC circuit breaker above 1 kV, so the same three-tier logic applies — type tests for the design, routine tests for the unit, field tests for the condition. What changes is the severity of the duties and the complexity… Read More: HV Circuit Breaker Testing: What Changes Above 52 kV (IEC… »
A medium-voltage circuit breaker has one job that matters above all others: interrupt a fault current safely, on demand, possibly after sitting closed and untouched for years. Testing exists to prove it still can. But “circuit breaker testing” covers three completely different activities done by three different people in three different places — and most of the confusion… Read More: MV Circuit Breaker Testing: Type, Routine & Field Tests (IEC… »
A lightning strike on a transmission line lasts microseconds. A power transformer is designed to run for forty years. The lightning impulse test is the bridge between those two facts — it proves, in the factory, that the transformer can survive the microsecond event so it can deliver the four decades of service. The test applies a standardized… Read More: Lightning Impulse Testing for Power Transformers: Why It Works and… »
If you’ve been doing motor insulation testing for any length of time, you’ve heard the standard cited a hundred times. “IEEE 43 says the PI minimum is 2.0.” “IEEE 43 requires correction to 40°C.” Most techs and engineers work from the rules without ever opening the document. That works fine until it doesn’t. Until an auditor asks where… Read More: IEEE 43-2013 Explained: A Clause-by-Clause Guide to Motor Insulation Testing… »