Portable Test Systems

Dynex has a range of small portable test equipment, for the testing of Power Semiconductors and contact resistance checks in the field.

Dynex Portable Test Equipment

Dynex has developed a number of portable test systems to assist in the testing of power semiconductors and high power electronic systems in the field. These range from standard Go-Nogo assessment systems to units that provide data for test and maintenance engineers. For a number of customers, we have also developed test “boxes” for power systems testing which are designed around the bespoke operation of the specific system. These can be optical signal assessment units as well as hard wired power testers (mostly operating at low voltage for safety). These can be programmed to digitally sequence test a more complicated sub system.

Portable GTO Tester

This tester is designed to enable the engineer to assess the operational health of GTOs that are already in a circuit. In railway traction modules it is often difficult to remove components or subsections to allow testing, so we can provide the specific interface connectors for your unit to be tested making field testing as simple as possible.

With Dynex’s experience, GTO devices rarely fail in a subtle way, when they do fail after many years of service, it tends to make the devices completely unserviceable, so this tester provides a simple low voltage (50V) assessment that the device under test is capable of turning on and off and is not in a short circuit or low resistance condition.
The connection configuration shown is to enable simple connections to the ABB oil filled valve modules used in a number of locomotive drive designs. (DB Shenker, GBRF, Brush Traction all use these).

Contact Resistance Checker

In high power systems, the busbar connections are prone to oxidation through time and a simple low current multimeter check will show a general “connection” of low resistance. It is important to test the joints with a more representative current and to measure the contact resistance at this higher current.

The Dynex contact resistance tester forces up to 100A d.c. through the joint and with Kelvin contact probes it can return an accurate measurement of the resistance across the joint.

This can be used for simple busbar or cable joints as well as the critical joints between the semiconductor pole-faces and the power connections.

Power Semiconductor Tester

This power semiconductor tester from Dynex is capable of providing a more rigorous test on the semiconductor devices which will assess the switching high voltage blocking capability up to 5kV. This can be used for field testing of SCR Thyristors, GTOs, Diodes and IGBTs. A clamping unit is supplied to ensure good positive clamping of the pressure contact semiconductors. The gate signal is a simple low voltage d.c. signal to provide a hard switching event.