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Circuit breakers help with global compliance

A Siemens Automation and Drives product story

Edited by the Engineeringtalk editorial team Feb 27, 2004

Compact high-capacity air circuit breakers approved to both IEC and UL standards are helping a leading British manufacturer of load banks meet the needs of the global market.

Siemens Automation and Drives is helping a leading British manufacturer of load banks meet the needs of the global market, by providing compact, high-capacity air circuit breakers (ACBs) which are approved to both IEC and UL standards.

Based in Stamford, Lincolnshire, NJ Froment and Co is a leading manufacturer of load banks for the load testing of power generator sets and UPS systems.

The company's Proofloader load bank system is used the world over to ensure generating systems meet their specifications, to prove that a given generator set will perform when it is installed with all systems fitted, and to provide regular test loads for strategic power supplies.

Proofloader load banks can provide both resistive and inductive load in a single system, with capacities up to 6MVA.

Available in permanently installable or easily removable versions, the Proofloaders come in a range of sizes, with the largest housed in 20ft ISO shipping container sized enclosures.

Critical protection and isolation within the load banks is provided by a pair of 4000A ACBs.

To meet global supply requirements for the containerised load banks, Froment looked to source a range of ACBs that carried both IEC and UL approvals.

The company was prepared to significantly redesign the Proofloaders to accommodate the new ACBs, but with a very high density of equipment within each Proofloader, space was at a premium, so the size of the ACBs and the associated busbars was critical to meeting the rating, cooling, spacing and installation standards.

Having used Siemens ACBs before, Froment's Managing Director Keith Williamson was keen to see whether the company had a product that could meet Froment's needs.

Siemens responded with the recently launched 3WL5 - a compact, dual standard (IEC/UL) ACB, rated at full capacity at ambient temperatures up to 55C, and with adaptable and flexible terminal arrangements allowing customised power connections.

"As well as the new Siemens product, we investigated a number of other ACBs from various manufacturers, to get the best picture of our options", says Williamson.

"We had strict requirements in terms of the ACB specifications, its price and our delivery window.

But while a number of these manufacturers could meet two of our three requirements, only Siemens was able to meet them all".

With much of the market for load banks being for the proving of new generator systems, short term leasing of these products is commonplace, and equipment rental companies account for a significant percentage of Froment's sales.

These rental companies often operate globally, so the ability of the load banks to meet local standards is critical.

Williamson explains: "One of our load banks could be in the USA one month and in Singapore the next so it's important that we can build them to meet the widest possible range of regional standards.

For our products to be used across North and South America, Asia and Europe, we have to ensure that the critical components in the load banks comply with multiple standards and meet the requirements of the various approval and inspection bodies.

These components must also be rated to operate, without derating in environments up to 55C".

Froment has now modified its Proofloader design to accommodate the Siemens 3WL5 ACB in the containerised load banks, and the first new products are already en route to join a global load bank fleet.

As a further benefit, mechanically identical versions of the ACB are available to IEC standards only, at reduced cost, allowing Froment to standardise construction of the Proofloader for use where dual-standard construction is not required.