lembede
Electrical
- May 27, 2003
- 2
I have a classified trip request signal from the emergency shutdown system to trip the main contactor in the thyristor control panel for a heater (435kW). The contactor has to be classified to SIL 2 according to IEC 61508, which means it must not fail to trip more than once in 1000 requests to trip (as a worst case).
Is there an off-the-shelf contactor with this classification, rated 400V (50 Hz)630 Amps? There are only four of these in this application and local suppliers are not prepared to go through the certification process for such a few.
Do you think using a contactor with utilisation category AC-4 (according to IEC 947-4) would be a justifiable solution?
Your help will be appreciated.
lembede
Is there an off-the-shelf contactor with this classification, rated 400V (50 Hz)630 Amps? There are only four of these in this application and local suppliers are not prepared to go through the certification process for such a few.
Do you think using a contactor with utilisation category AC-4 (according to IEC 947-4) would be a justifiable solution?
Your help will be appreciated.
lembede