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When test before you sell beats try before you buy

The saying try before you buy must be as old as time itself. But here at Cressall we pride ourselves on being different, so we’ve created another saying: 100% test before you sell. In fact, we believe all electrical manufacturers should apply this one!

So, applying our 100 per cent test before you sell motto, we have recently equipped our Leicester headquarters with an impulse test facility, which enables us to carry out impulse tests of up to 400,000 Volts. Impressive – right? Read on, it gets better.

Our impulse voltage unit is a 10kJ, four stage generator with up to 100kV per stage. In order to ensure the safety of our testing team and other members of staff, we’ve created a purpose built test area. The area is fully secured, interlocked, boasts bright warning lights and an alarm sounder, all of which prevent unauthorised personnel from entering.

The equipment is used in conjunction with a four channel digital oscilloscope. Our oscilloscope has a sample rate of five Gs/s and a nine bit vertical resolution, which helps us produce and save the required wave shapes.

Much of the equipment we manufacture is for use in high voltage applications and safety critical systems, both here in the UK and abroad. Customers specify the fault voltage that our equipment must withstand, and – although we ensure all of the components we use meet and exceed these demands – in order to prove designs and test prototypes, we always 100% test and inspect our equipment in our fully equipped test bay. The impulse test facility helps us take that to another level in a totally separate and secure area.

For instance, this week we are testing a standard high voltage mesh bank construction. We know it is suitable for 50kV per bank, but we’ve never had the opportunity to see if it could operate at higher voltages. The tests we’ve conducted so far indicate that the mesh would be suitable for at least 70kV per bank, so now we know without shadow of a doubt, this bank operating at 50kV is well within its limits.

Knowing by exactly how much an application has been over-specified is very important; it enables us to use more closely specified banks in future designs – potentially reducing cost for the end user. This increases our competitiveness as a supplier of high voltage load banks or filter resistors.

Having a high tech in-house testing facility is beneficial for the products we manufacture, but it also gives us an additional edge in our sector. We are now able to offer complete testing services to other equipment manufacturers. ‘100% test before you sell.’

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