How to handle grid fluctuations during thunderstorm weather?
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The summer thunderstorm season has arrived again; the large motors here often trip due to sudden fluctuations in the power grid, resulting in shutdowns. In fact, the circuit breaks and trips only because the voltage required to energize the coil of the contactor (or circuit breaker) drops momentarily. The motor still has considerable inertia, and if the contactor does not break, it will not have any impact on production at all. Is it possible to keep the instantaneous fluctuations in the power grid within 2 seconds, so that the contactors (or circuit breakers) do not disconnect? However, pressing the stop button can bring it to a stop immediately. I would appreciate some guidance from an expert.
Hehe, I just read an article today about ways to prevent surge currents; some solutions involve varistors, which could be tried, though they might be a bit expensive.
You can try connecting an R-C circuit in parallel across the coil, using the capacitor to delay the release. It’s very troublesome, as each coil has to be installed, and resonance has to be prevented; it’s also necessary to calculate the capacitance value and so on.
It’s not necessary to use a contactor for each one; I once connected them to the control power supply in the drawer, in an attempt to prevent shutdowns caused by temporary voltage drops, but it didn’t work – perhaps the parameters weren’t set correctly.
Reply to 4# langdon88: Thank you, 4th floor! I hope you’ll study this as soon as possible; now, whenever it’s overcast, I’m extremely worried~
Install a surge protector! Power systems generally use reclosers!
Just install an anti-vibration relay; consider the cost and opt for one with a moderate price
For a short period, it is possible to use a self-locking time relay for power-off delay
Basically, with 2 seconds, it can be controlled using a relay