RD35
Hello. First post, so please forgive me if I am doing this wrong in any way.
I am researching some options for load shedding. I came across these SMM modules by Generac. They appear to have only four wire termination points for power (two-pole contactor) and no control wiring from outside the box. If this is true, then can someone please explain to me how this module can know when the line power is from the generator. (The module needs to know this in order to disconnect its load during generator operation if the lock-out mode is selected....right??)
Thanks
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RD35
Okay, I was really needing an answer quick so was looking in several places at once including this forum. Well, I just finished a chat session with Alex at Generac. He answered my questions. As it turns out these modules are able to sense fluctuations in frequency very precisely and can determine if the line power is coming from a generator based solely on this frequency behavior information. No control wires required. During the 5-minute delay period for brining managed loads on-line, the modules also do a confirmation test by performing a "soft test" of the load (bumping the contactor) to confirm that the line power is generator derived. This way, it can accurately determine when to bring the loads back on line or, more importantly, leave them off-line if the lock-out feature has been enabled. Very impressive design!
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