Cressall

Power Resistors

Testing Facilities

Testing and test equipment

We have calibrated test equipment for all routine testing, including resistance and inductance meters, temperature gauges and a 100kV dielectric tester.
For high power or high voltage testing, including impulse tests up to 400kV and full load testing of load banks and brake resistors, we have access to the best-equipped test laboratory of any resistor manufacturer in the world.
This is used both for in-house development and for routine and type-testing customers’ equipment.

Controlled power supply

A 1.5kV chopper-controlled DC power source, continuously rated at 1.5MW, enables us to test resistors at full load power and under simulated cyclic conditions. Full-scale test results are at the heart of all our design models and enable us to produce designs that are ‘right first time’.

Resistor test bay control system

Test bay control system with the test curve shown on the monitor.

Impulse test to 400kV

We have a 400kV impulse generator on site in Leicester which is used for dielectric and through impulse tests of our equipment.

Impulse test stack for resistors

Impulse test stack with spark gap settings

Thermovision equipment

A recording thermal vision camera is used to identify hot spots and ensure that designers have an accurate picture of the overall thermal performance of their products, particularly in traction applications where space and weight constraints make good airflow design essential.

2M x 2M Vibration Table

vibration table for testing resistor designs
We have two 2000kg capacity hydraulically driven vibration tables (with vertical and horizontal axes respectively) for vibration, shock and seismic tests. Traction resistor tests are carried out to IEC Standard 60373. We have the capability to carry out dynamic strength tests, long life tests, road simulations and noise level measurements, as well as static and dynamic finite element analysis of resistor structures.

Computerised data logging

The test laboratory is equipped with computer-controlled 32 channel data logging equipment and optically-isolated transducers for high voltage measurement and recording. Test variables such as temperature, power and current are also recorded.

Data logging equipment for resistor development

Impulse test for pre-insertion resistors

We have access to other test facilities, as shown here, as a Cressall Pre-Insertion Resistor is prepared for RIV (Radio Interference Voltage) and through impulse testing. It passed the RIV test at 275kV and the through impulse tests at 475kV.