IEC 61000-4-11 and 61000-4-34
voltage dip immunity standards

Both standards specify the same depths and durations of voltage dips, and explain how to apply these dips to single-phase and three-phase equipment. 61000-4-11 applies to equipment rated up to 16 amps per phase, and 61000-4-34 applies to equipment rated at more than 16 amps per phase; otherwise, the two standards are essentially identical. PSL was deeply involved with developing and writing both standards. The PSL Industrial Power Corruptor is essentially the reference design for test equipment specified by these standards. Although these standards are similar to the SEMI F47 standard, they use slightly different dip depths. These standards also make the three-phase testing vectors much clearer than SEMI F47.
A typical IEC 61000-4-11 voltage dip (top) and how it affects a power supply (bottom).
Just like SEMI F47, this problem was fixed by increasing the size of a capacitor, at a cost of a few dollars.

How do you test for compliance with these standards?

Insert a voltage dip generator in series with the mains cable of the equipment under test. Use the voltage dip generator to create the voltage dips specified in the standards, and verify that the equipment under test works properly. That's all there is to it! PSL can help you with on-site certifications services, or we can work with you to provide a third-party certification of your own testing - see our TestingPartner program. For smaller products, testing at PSL's lab can be the lowest cost approach. Contact us, and we'll get you started!
IEC 61000-4-11 and 61000-4-34 are a pair of standards that set the requirements for voltage dip immunity. 61000-4-11 is for equipment that is rated at 16 amps per phase or less, and 61000-4-34 is for larger equipment.