Product category:
Industrial Motors
News Release from: Rockwell Automation | Subject: Motor starters
Edited by the Engineeringtalk Editorial
Team on 18 May 2001
Motor starters tested to BSEN 60439
Allen-Bradley starters, installed in a Motor Control Centre manufactured by leading supplier Rolla Ltd, have successfully completed heat rise and short circuit tests to BSEN 60439
Rockwell Automation is pleased to announce that Allen-Bradley starters, installed in a Motor Control Centre manufactured by leading supplier Rolla Ltd, have successfully completed heat rise and short circuit tests to BSEN 60439 This means that Rockwell Automation can now offer a high quality, independently accredited MCC package to its panel builder customers
An increasing number of users of MCCs are demanding such approvals as part of their standard specification.
However, the testing of individual cubicles is a costly exercise and can only be carried out by authorised testing stations.
For panel builders with limited resources, these costs can prevent access to a large potential market.
Rockwell Automation commissioned tests on a Rolla MCC fitted with Allen-Bradley starters.
The heat rise test was completed to BSEN 60439-1:1999 sub clause 8.2.1.
and ASTA certified.
It was made using an IP54 Rolla MCC section complete with mains and dropper busbars.
The test was conducted at the maximum packing density using 18 Allen-Bradley 22kW (45A) intelligent direct-on-line starters.
Using the data from these tests, the panel builder can calculate by extrapolation for any other combinations such as reversing or star delta starters.
The second test was for short circuit performance and was conducted on a fully wired assembly to validate the effect of short circuit stresses on the conductors between the main busbars and the supply side of the outgoing motor starter.
This is as defined in BSEN 60439-1 subclause 7.5.5.1.2.
and also referred to as the 'fault free zone'.
Users are increasingly requiring evidence that this area has the same short circuit capacity as the main busbars.
To provide a worst-case scenario at different ratings, three different frame sizes of 140-M circuit breaker and contactor were tested to cover a range of motor applications.
22kW, 11kW and 7.5kW starters were used with 10.00 mmę, 4.0 mmę and 2.5 mmę Tri-rated cable respectively.
Short circuit tests were made to BSEN 60439-1 sub clause 8.2.3.2.3a at 50 kA for each starter rating.
The tests used a shorting link fitted to the outgoing terminals on the contactor within the MCC.
In each case, the fast operation of the Allen-Bradley 140M circuit breaker limited the fault current to less than 10kA and the combination cleared the fault without damage to the interconnecting cabling.
The speed of the 140M limited energy let through obviating the need to uprate the connecting cables or provide additional bracing.
There was no damage to the contactor or circuit breaker.
The successful completion of these tests means that panel builders will be able to offer the Rolla high quality range of MCCs fitted with class leading motor starters from the Allen-Bradley Modular Control System.
The combination has the benefit of inherent short circuit and type approval to BSEN 60439.
News of the success will be of interest to all panel builders, particularly the smaller independent companies, that now have an attractive and competitive product to offer to this important area of the market. Request a free brochure from Rockwell Automation ...
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