Haefely Test AG is market leader in various high-voltage test products including the test, measurement and diagnostic equipment for a wide range of electrical applications. Test systems for laboratory, factory and field use are available. Haefely a single source supplier unifying powerful resources from design, development, engineering, marketing and support - from high-voltage design over electronics to software in one company. Impulse voltage testing Impulse current testing Alternating voltage ac testing High-voltage construction kit C & tan delta (power factor) measurement Instrument transformer measurement Resistance measurement Partial discharge pd measurement Transformer measurement