Generator - exercising

[laurice@email.com]

Quick question. Can I exercise my generator while on shore power?  I just replaced the automatic transfer switch and not sure if the exercising was the cause or nearly a coincidence. Thanks in advance

Laurice

[1nolaguy]

Assuming you have an on-board generator, consider exercising it when you move. I generally do this once month when moving from one CG to another. I try to run the generator while on the freeway so it gets good air exchange and I run the A/C or Heat Pump as a load about the last 15-20 minutes before I get to my stop to cool down or warm up the living quarters as needed.

[cbr046]

If there was load on the transfer switch while it switched that could be an issue (switching under load), but I doubt the exercising was the cause. 

- bob

[96 EVO]

30 minutes ago, laurice@email.com said:

Quick question. Can I exercise my generator while on shore power?  I just replaced the automatic transfer switch and not sure if the exercising was the cause or nearly a coincidence. Thanks in advance

Laurice

Remove any large loads before starting the generator and it will usually be fine.

I burned up the gen time delay board in my transfer switch doing what you want to do, when my gen didn't start due to a problem under the hood!

I now shut off the shore power breaker before starting the generator!

Edited November 8, 2023 by 96 EVO

[laurice@email.com]

Thanks all. Great information and confirmed was I thinking.  
we are full timers in southern BC so it can get a little col in the winter but based on your advise, we’ll venture out and throw the main break going forward. 
m

Many thanks for the info. Much appreciated 

[96 EVO]

I'm on the west coast of B.C.

I've visited Fort Steele. Cool little place!

[CAT Stephen]

Laurice,

 

Although transfer switches are designed to transfer under load, arcing does occur under all loads and the arcing is heavier and more severe as the load increases.  Arcing causes corrosion of the electrical contactors within the transfer switch which results in eventual transfer switch failure.

So, should you use your transfer switch under load?  The answer is that is exactly what it is designed for.  But, since most all transfer switches are inherently slow in their load transfer (defined as the momentary absence of power during the transfer from shore to generator or generator to shore), your air conditioners, microwaves, and clothes washers will cycle off during the transfer which is not helpful.  Thus, its better to power off the heavy loads before the transfer as they will just cause more arcing with no other benefit which reduces the service life of your transfer switch.

Also, keep in mind that all RV transfer switches are set from the factory as being generator preferred.  What this means is that the transfer switch will activate within a preset time (30 seconds to 2 minutes depending on your transfer switch) switching the load from shore to generator even if your RV is attached to shore power.

Your results may vary as some transfer switches have DIP switches to adjust the generator preference to shore power preference.

[laurice@email.com]

Great response.  Thank you so much. 

[Rocketman3]

One other issue of having the shore on and then starting the generator is when the transfer happens the sign waves of the power will not be in sync and probably not even close. (The same thing when running the generator then shutting it down and the transfer switch immediately switches back to grid).

While this will be fine for some loads - it can cause problems for other items - especially stuff with computer chips in them.

[1nolaguy]

As a rule of thumb, it is just better when you are going to exercise your generator, and you are plugged into shore power, turn off the breakers at the pedestal before you start the generator and cut off the generator before you turn on the breakers again. That keeps the systems separate and  buts less strain on the transfer switch.

[laurice@email.com]

Thanks all. Much appreciated