dcg9381
Well-known member
I've been building a residence. Don't worry, I've done it right, we've been living in the shop for about 2 years now (the spouse is starting to get impatient, she's been a TROOPER on a chemical toilet). Hopefully we'll finish it up in the next 30-60 days. That house has a 20KW generator (Generac) and ATS system. I did quite a bit of the main electrical ranging from 320A service, 2 x 200A panels, shop, residential ATS, generator, 6KW solar system, and "load shed" modules.
This has taken years.
I'd like to discuss - as I've seen almost no information on - Generac's "Load Shed" modules. Generac calls them Smart Management Module (SMM). They They come in 50A and 100A and look like this:
I have two of these in my residence. Once of them (100A) offloads the garage and a garage apartment. The other (50A) offloads one of the main residential HVAC systems.
These require no wires to the ATS. They are simply hooked up (240V) to feed of a 240V device or sub-panel. They disconnect both hots and past through the neutral and ground.
They're designed to drop load when the generator is working too hard. Yet they have no wires or interface back to the generator itself. This stumped me for a while, and certainly stumped my electrician.
So how do they work?
These things are "dumb timers". What that means is that when utility power drops, they open a contactor (fancy word for 240V relay). That contactor stays open for a number of minutes, 6-10, depending on the setting of "priority".
So as soon as utility power stops, these cut downstream power, the generator auto starts, and these then turn back on at designated timings. You have them turn on at different times.
The only "smart" thing they do is monitor line frequency. If the line frequency drops below 58 Hz, they assume the generator is "lugging" and they'll drop out again for another designated period of 6-10 minutes.
They do have an electrical "buzz" (electromagnet) when they are on.
Mystery solved.. At least for me. Hope this helps someone else and their electricians.
This has taken years.
I'd like to discuss - as I've seen almost no information on - Generac's "Load Shed" modules. Generac calls them Smart Management Module (SMM). They They come in 50A and 100A and look like this:
I have two of these in my residence. Once of them (100A) offloads the garage and a garage apartment. The other (50A) offloads one of the main residential HVAC systems.
These require no wires to the ATS. They are simply hooked up (240V) to feed of a 240V device or sub-panel. They disconnect both hots and past through the neutral and ground.
They're designed to drop load when the generator is working too hard. Yet they have no wires or interface back to the generator itself. This stumped me for a while, and certainly stumped my electrician.
So how do they work?
These things are "dumb timers". What that means is that when utility power drops, they open a contactor (fancy word for 240V relay). That contactor stays open for a number of minutes, 6-10, depending on the setting of "priority".
So as soon as utility power stops, these cut downstream power, the generator auto starts, and these then turn back on at designated timings. You have them turn on at different times.
The only "smart" thing they do is monitor line frequency. If the line frequency drops below 58 Hz, they assume the generator is "lugging" and they'll drop out again for another designated period of 6-10 minutes.
They do have an electrical "buzz" (electromagnet) when they are on.
Mystery solved.. At least for me. Hope this helps someone else and their electricians.