How long can the coil of an AC contactor remain energized after a power loss? ?
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This post was last edited by Bohai Taotao on 2021-2-1 09:47. RT: How long can the coil of an AC contactor remain magnetized after the power supply is cut off? In other words, how long does it take before the main circuit stops functioning in the event of a power loss? Of course, this time value must be on the order of milliseconds, or even less. Where can I find relevant data on this? ? ? For example, Chint’s NC3-170 contactor, and Renmin’s SRMC-170 contactor.
How do I find out what it is at 0.1? ?
This is probably not related to time, but rather to the level to which the voltage drops. If there are many rotating devices, the bus voltage drops slowly, making it difficult to release the device; in such cases, it’s necessary to check the release voltage of the contactor coil
Generally, it does not exceed three cycles, that is, 60ms
Is this based on experience or are there standard requirements? ? ?
Everyone says that, and I haven’t found any source either
Why worry about this issue? Generally, in communication contactors, if the voltage drops below 70% (80% for DC) and this condition persists for more than 20 ms, the relay will trip. However, this time is not reliable, as it is affected by hysteresis caused by the manufacturing process as well as contamination on the armature engagement surface. What you should focus on is ensuring the reliability of power supply for the control circuit; methods such as using UPS systems can be employed to address this issue.