Conclusion

AN1296

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Doc ID 8159 Rev 3

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Conclusion

Ring wave surges, as defined in the UL858A, can be applied on systems including ACSs as

long as the loads used are also compatible with the UL858A.

●

Valves: 50% of the tested valves sustain the 6 kV surge. In this case, ACSs are

compatible with the 100 kHz ring wave defined in the UL858A.

●

Pumps: driven by an ACS, it is compatible with the UL858A. These loads can be up to

700 mA. In these case, thermal behavior has to be mastered to keep the junction below

maximum junction temperature.

●

For a 150

Ω resistor, which seems to be the worst case for the power range of the

targeted loads, ACSs also are in line with the UL858A standard without any risk of

damage.

ACSs comply with the UL858A when the loads are able to withstand the required level of

voltage (6 kV). If not, a spark gap can be implemented by bringing closer the two non-

insulated copper tracks where the mains plug is connected. A 3 mm distance will reduce the

input over voltages to approximately 3 kV.