Wilco Custom Fixture Build

Voltech offers many solutions to creating your own test fixture, but you may prefer a full turn-key build service.
Voltech have worked with fixture partner Wilco Control Service, based in Massachusetts, USA for over 20 years.
Wilco Control Services is a Voltech recommended global fixture manufacturer and has the capabilities and experience to create a fully customised fixture solution for your AT tester, anywhere in the world.

Please see below examples of their work.
If you are interested in obtaining a quote for a customer fixture made to suit your transformer then please contact WILCO directly and they will help you.
For more information, please visit their website

1. Pinned Transformer Fixture Using True Kelvin Blades

Pictured fixture is for the Wurth SMPS 750811290.
The fixture block contains 2 rows of Kelvin blades at 5mm pitch, with a row spacing of 25mm.
The transformer shown uses 9 of the 12 pins, but as the fixture is fully wired, it can be re-used on ANY transformer with the same footprint.
The Kelvin blades allows compensation to remove any parasitic effects of the fixture.
The fixture also contains an additional spring probe used to test the core-to-winding isolation

Typical cost around - 400 USD.
Typical life time > 100,000 tests
Typical cost per test < 0.01 USD

2. Surface Mount Transformer Fixture Using True Kelvin Blades

Here shown is a fixture for a Coiltronics CCFL transformer (CTX21607-R)
The socket used is a ZIF (zero insertion force) style socket.
The lever above the socket opens and closes the contact pins in the horizontal plane.
This means that no vertical force is applied to the gull wing transformer pins, which would result in damage to the legs.

Each pin still has two connections, thus allowing a true Kelvin connection to the item under test.This in turn allows the AT Tester to compensate out the effects of the fixtures (natural contact resistance, wire resistance and wire capacitance) from your readings. Hence you get a true value each and every time.
This is especially important when coil resistances are low (typically <0.5Ohm) where contact resistance becomes more of a factor.

Blade lifetime is in excess of 50,000 insertions.
Typical cost around - 525 USD.
Typical life time > 50,000 tests
Typical cost per test < 0.01 USD

3. Planar Transformer Fixture Using Dual Spring Probes

This example shows a WURTH SMPS power transformer (#750341144)
The part has 6 flat SMT contacts on the bottom of the transformer, and presents a problem for standard Kelvin pin type connections.
The solution here is to use two vertical spring probes for each pin, mounted in a locating recess.
The locating recess also provides a quick and easy location guide for the transformer and the yellow plate is spring loaded.
When the clamp is engaged, the plate lowers and the transformer is accurately and evenly pushed onto the test pins..Each pin still has two connections, still allowing a true Kelvin connection to the item under test.
This in turn allows the AT Tester to compensate out the effects of the fixture wiring.
This is especially important when coil resistances are low (typically <1.0 Ohm) where contact resistance becomes more of a factor.

Operation lifetime is in excess of 50,000 insertions.
Typical cost around - 525 USD
Typical life time > 50,000 tests
Typical cost per test < 0.01 USD

4. 'Adjusto' fixtures

Wilco's "Adjusto" fixture adds even more flexibility and versatility to your fixturing.
These allow the row pitch to be altered on the fixture so that several bobbin widths can be accommodated by the same fixture.
The pictures show the testing of a 16 pin SMPS transformer, with 5 mm pin pitch and 30 mm row pitch (which also uses the 4mm banana sockets for Screen and Core hi-pot testing)
The same fixture is then used for a 10 pin PFC transformer, with 5mm pin pitch and 18 mm row pitch.

All standard pitches = $650.00 USD
Typical life time > 100,000 tests
Typical cost per test < 0.01 USD

Specifications:
Adjustable Row Spacing = 300" (7.6 mm) to 2.1" (53.34 mm) / Lead diameter .020" (0.5 mm) to 0.060" (1.5 mm) / Minimum lead length .160" (4mm) / Contact material BeCu gold over hard nickel / Custom versions also available.

Available pitches:
WCS-0197 0.197" (5 mm)
WCS-0200 0.200" (5.08 mm)
WCS-0150 0.150" (3.81 mm)
WCS-0100 0.100" (2.54 mm)
WCS-098 (2.5 mm)