Qualification
Whoever the customer, whatever the application, the product has to work. Viable Power prides itself on its commitment to quality and stands by every product we produce. This commitment starts at the proposal phase and is maintained throughout the life cycle of every product.
During the design and development phase, Viable Power’s team of engineers addresses each requirement to ensure that it is capable of meeting all the performance criteria. A detailed compliance matrix is prepared which states the expected performance for each requirement.
The matrix also identifies the method of verification, be it analysis, test, inspection, demonstration or similarity, and at what phase each requirement is verified. A combination of the listed verification methods qualifies the product’s performance against the requirements. Upon successful completion and with customer concurrence, the product is considered qualified.
Acceptance Test Sequence
Every product manufactured undergoes an acceptance test sequence consisting of a series of functional tests (Acceptance Test Procedure, ATP) and a series of Environmental Stress Screening (ESS) tests which include vibration testing (single or three axis) and thermal cycling. These tests are designed to address infant mortality and identifying manufacturing imperfections. After a successful Acceptance Test Sequence, a product is considered acceptable to deliver to a customer.
The performance characteristics tested during acceptance is a subset of all the performance characteristics. Those tested are usually the basic characteristics such as inrush current limiting, line and load regulation, hold up, output ripple, over and under voltage protections, current limits, power factor and efficiency, for example.
Qualification Tests
For those performance characteristics that are not included in the acceptance test sequence, they are addressed in a series of stringent tests, or Qualification Tests. These tests are performed on a dedicated ‘Qualification’ unit (or units) which are manufactured to the identical configuration as a standard production unit, in fact they are tested to the full acceptance test sequence prior to undergoing any qualification level tests.
The qualification tests include any remaining electrical performance characteristics not covered during acceptance testing plus any applicable environmental tests.
Environmental Tests
The environmental tests may include 3 axis random vibration at design levels, shock, bench handling shock, functional and crash safety shock, storage temperature, temperature shock, temperature and altitude, humidity, immersion and rain/spray and salt fog.
Electrical Tests
The electrical tests may include phase imbalance, phase failure, power factor and distortion, dynamic loading, input transient tests, output sequencing, output transition times, remote sense voltage drop, remote sense line shorting, load capacitance, inrush current plus full characterization across the temperature range of key performance parameters such as load and line regulation, efficiency and power factor.
Electromagnetic Tests
The electromagnetic compatibility (EMC) tests are performed to ensure compliance to the relevant standards. Those tests are typically performed in accordance with MIL-STD-461 and MIL-STD-462 by an accredited test facility.
Using Dedicated Qualification Units
Viable Power uses dedicated qualification units for the stringent qualification tests as the test levels, particularly the environmental tests, can be so high that they may reduce the long-term life expectancy of a particular unit. Once all these tests have been satisfactorily completed the design is considered ‘qualified’, as such the design standard is considered fixed.
During the lifecycle of the product, if any changes are required, most likely due to parts obsolescence, any changes are carefully assessed as to their impact to any performance characteristic before being approved and incorporated. If necessary, some qualification tests may be repeated to re-verify performance.
Contact Our Experts
Viable Power qualified experts are available to answer any questions you might have about our qualification process. Feel free to contact us to speak with one of them.
If you would like to know more about our custom power supply units, please visit our Power Supply Solutions page.
