Automatic Transfer Switch

[Papote]

Has anyone used any of these Chinese AC Automatic Transfer Switches?

I have been looking into the Geya W2R-3P.
I'm planning on using one of these, but at the moment using it as a manual bypass if I need to connect inverter output or generator to breaker panel. I don't really see what's the thickest wire (AWG) these devices hold. They say they work up to 100 amps @ 110V AC. I've messaged them, but get conflicting responses.

 

[timselectric]

Rated working current is 63a.
So, a 60a breaker and #6 is what you want to use. (Maximum)
You may have to use a lug or crimp terminal to connect to it. If the existing terminal won't accept #6.

 

[beastman]

I personally would not run more than 30a through it. Might be a great setup for a portable generator like the tri-fuel firman's sold by costco (7500w).

 

[iwish2fish]

Anyone know anything about an automatic 3 way transfer switch? I found one on Amazon. No idea what the brand is. It would be perfect for my rv. I have shore power generator and inverter. 1.2 kw solar but lacking some batteries. More will be added. Anyway the switch I'm looking at has all the inputs sharing the neutral and isolating the hots. Not sure that's a good or bad thing. Any thoughts?

Automatic Transfer Switch,Automatic Switching Between Utility Power、Generator and Inverter,Overcurrent Protection,Overvoltage and undervoltage Protection,63A https://a.co/d/6TGwgQC

 

[Aridom82]

Has anyone used any of these Chinese AC Automatic Transfer Switches?

I have been looking into the Geya W2R-3P.
I'm planning on using one of these, but at the moment using it as a manual bypass if I need to connect inverter output or generator to breaker panel. I don't really see what's the thickest wire (AWG) these devices hold. They say they work up to 100 amps @ 110V AC. I've messaged them, but get conflicting responses.

I am using two chinese ats in my system. They switch fast from solar to grid, but they are slow from grid to solar so if you are using a computer or a modem you need a ups to avoid them shutting off.

 

[Papote]

I am using two chinese ats in my system. They switch fast from solar to grid, but they are slow from grid to solar so if you are using a computer or a modem you need a ups to avoid them shutting off.

Are you using 2 in parallel?
Do you have pictures?

 

[timselectric]

Are you using 2 in parallel?
Do you have pictures?

Two in parallel would not be safe.
The purpose of a transfer switch is to switch between sources, without the possibility of connecting to both sources at once.
You need to choose one that is large enough, on its own.

 

[Aridom82]

Are you using 2 in parallel?
Do you have pictures?

I am using a three phase one for my warehouse and a single phase one for my appartment in the same building.
I have them so i can switch manually to grid power.
This photo is from when i installed and tested them first a couple of months ago.

 

[daklein]

I am using two chinese ats in my system. They switch fast from solar to grid, but they are slow from grid to solar so if you are using a computer or a modem you need a ups to avoid them shutting off.

How slow is slow? Is the slower time occurring in the detection of the grid going away, or taking longer to switch once it has triggered? These have an internal control relay that runs the solenoids to move the contacts.

 

[OffGridInTheCity]

I use 4 x Progressive - https://www.amazon.com/gp/product/B003VAWNVK/ref=ppx_yo_dt_b_search_asin_title - for 240v/120v US Split-phase and 2 x Go-Power - https://www.amazon.com/dp/B00153EYTO ATSs for 120v over the last 6 years in my off-grid solar system.

I use these because they're UL/ETL listed to switch between grid and solar powered inverter. Also use refurbished APC UPSs for sensitive (computer, tivo, etc) circuits as mechanical relays just aren't fast enough during back/forth between grid and inverter. Sometimes they'll switch fast enough but mostly not. I wouldn't think the one in the link above would be better.

While my system works well and is low maint... lately I've become a I'm a fan of AIO(s) with built-in APS/UPS if one want's to run an off-grid system. I have an MPP Solar 3048LV in my trailer and it works great.

Warning: The mechanical interlock on the Progressive(s) tend to stick after 4-5 years of switching (~3,000 switches) - so I have to replace the relay mechanism. It's not catastrophic because it will stick on grid rather than completely fail. Have replaced 3 of 4 so far during the my 6 years of operations and I don't have to 'rewire' since I don't have replace the metal box/conduit/wire - just the relays. But it's not as long a service period as I was hoping.

 

[Aridom82]

How slow is slow? Is the slower time occurring in the detection of the grid going away, or taking longer to switch once it has triggered? These have an internal control relay that runs the solenoids to move the contacts.

About 0,5 to 1 second. Once the grid power is shut off it needs that time to connect to solar so there is that time (0,5 to 1 second) of power interruption. Idk about the internal mechanism, this is just what i have observed.

 

[daklein]

I think I will be using one of these, to switch a heat pump load between grid and off-grid inverter. It will only be up to 20a continuous load, it's an inverter heat pump so there are not any startup surges. If it does switch real fast sometimes causing a discontinuity sort of spike in the AC waveform, the inverter heat pump load is not a spinning hard-wired motor. I don't know that I'd use one of these little transfer switches for a whole house load.

 

[daklein]

This explains and shows what happens with a fast transfer switch, with rotating PSC motors like motor compressor, fan or blower motors. Not the end of the world, just a little clunk maybe, but likely not good for parts of the system. https://diy.stackexchange.com/quest...-before-transfer-back-to-utility-from-generac

 

[daklein]

A while back, I made this contactor transfer switch, and it's been working fine with no trouble for 2+ years now. I wanted at least several seconds between switching sources, so that the microinverters would not potentially be connected out of phase, moving to/from the grid and off-grid system The off-grid system is typically not in phase with the grid). https://diysolarforum.com/threads/diy-timer-controllable-transfer-switch-contactor-box.25702/

 

[Aridom82]

I think I will be using one of these, to switch a heat pump load between grid and off-grid inverter. It will only be up to 20a continuous load, it's an inverter heat pump so there are not any startup surges. If it does switch real fast sometimes causing a discontinuity sort of spike in the AC waveform, the inverter heat pump load is not a spinning hard-wired motor. I don't know that I'd use one of these little transfer switches for a whole house load.

Uf, i would not trust my dear heat pumps to my ATS without an UPS or some other protection. I am afraid that the abrupt switch or power interruption could damage the electronics. I have UPS protection in my workstation and Starlink antenna too.

 

[daklein]

Here's a detailed description of what's in this style of ATS, and how they work.

At around 23m in the video, there may be explanation about why grid to backup vs. backup to grid might be a different reaction time. I looks like the control relay coil is always energized by the grid. Maybe the control relay has a different reacting time to switch for energizing the relay coil, vs. de-energizing the coil.

 

[dagb]

Curious if anyone got any long-term experiences with this style of ATS.
The spec says "Electrical: 2000times; Mechanical:5000times" for the lifetime of the device. Are there any low-cost ATSes which can deliver more operations during the lifetime of the device?

My thought (for a design utilising an ATS) was to avoid all grid-tie complications and regulations by hooking up the water-heater (and eventually heat-pump) to an ATS and power these loads from battery when there is sufficient charge on the battery. But the somewhat limited lifetime of the ATS (in terms of number of operations) makes me question the suitability of this device for the purpose. At least for the design I had in my head, which doesn't have a lot of battery capacity.

The idea was to ensure that I can consume every drop of energy I produce, and back-fill any shortfall with grid power. And for this, I only need enough battery to hold a day's production minus whatever is consumed during production. The water heater can even be controlled to only run while there is production or when grid energy cost is at or below a certain minimum.

 

[Aridom82]

Curious if anyone got any long-term experiences with this style of ATS.
The spec says "Electrical: 2000times; Mechanical:5000times" for the lifetime of the device. Are there any low-cost ATSes which can deliver more operations during the lifetime of the device?

My thought (for a design utilising an ATS) was to avoid all grid-tie complications and regulations by hooking up the water-heater (and eventually heat-pump) to an ATS and power these loads from battery when there is sufficient charge on the battery. But the somewhat limited lifetime of the ATS (in terms of number of operations) makes me question the suitability of this device for the purpose. At least for the design I had in my head, which doesn't have a lot of battery capacity.

The idea was to ensure that I can consume every drop of energy I produce, and back-fill any shortfall with grid power. And for this, I only need enough battery to hold a day's production minus whatever is consumed during production. The water heater can even be controlled to only run while there is production or when grid energy cost is at or below a certain minimum.

I really dont use it for everyday switch from solar to grid. The inverter already does that. I have it for when i want to switch manually to do maintenance on the solar equipment and in auto mode to not have any power interruption if something goes wrong with the inverter and solar energy stops suddenly.