Where's the transfer switch?

[68 Overlander]

The ATS is a automatic switching relay that is prioritized to one circuit or the other, usually the generator depending on how its wired. Gen is usually selected as priority simply because most would not run the genny unless it were needed. If that circuit is lost, the automatic feature switches to the non-priority side in a few milliseconds to avoid loosing power. Conversely, there is a 30 second delay when powering back up the genset to let it get up to speed. Pretty simple device.

[lewster]

A quick word about inverters and transfer switches. Most 'quality' inverter unit ( like Magnum) already contain a fully integrated transfer mechanism that allow you to energize all of your 'inverter circuits' while on shore power.

These will be the same circuits that get energized while off-grid with the inverter 'on'. I'm not sure if the 1000 watt WFCO inverters that Airstream in now using have a transfer switch feature, as my only interaction with them has been removal and upgrade.

I did notice that they do ave a 120 VAC cord set and plug that are bundled but not used.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

[acstokes]

Well the verdict is in from AS and it is that there was once a transfer switch installed, but has been removed by someone for some reason.

But that's okay because now I have reason to upgrade and replace it. The original one would have been for switching between shore power and gen power. The one I intend to replace it with will automatically switch between shore power, gen power, and solar/inverter power. I like the one shown here:

AIMS 3-Way Auto Transfer Switch

Anyone own one of these or one they feel is better for 30 amp circuit?

[rmkrum]

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[Bbelk]

Originally Posted by FishinHatteras

It IS normal to have to turn a transfer switch inside of your rig if you are to use the front 30 amp male receptacle?

The transfer switch is important. It could be manual, but it is automatic in my 2010.

Its main purpose is to protect your generator from being exposed to the utility grid. If you were plugged in to the grid, and there was a power failure, you might start your generator. If there was not a transfer switch, your generator would attempt to re energize the entire grid.

A transfer switch is not necessary if your trailer only has one power inlet. If you have to unplug from the grid to plug into the generator, everything is cool.

[instax]

Mine is behind a panel in the rear under bed compartment, left side

[lewster]

Most automatic transfer switches (ATS) that I find in Airstreams are located directly behind the circuit breaker panel, and is an integrated part of the Parallax AC/DC power center. It is a steel box about 4" on each side.

An ATS is not required by code, as a manual device like a switch can be used, including a plug that you physically move from out receptacle to another (many older motor homes with generators used this plug-switching method; one plug from shore power cord and another from the generator that you simply connected to the receptacle that led to the breaker box.). The idea is to not allow shore voltage input from 2 source points into the power center at the same time.

If you research this Forum a bit, you will find several threads about the failures of these ATS devices and how many were left stranded with not 120VAC input power while camping. On some of my projects, I have removed the front power inlet from the power center and also removed the transfer switch at the owner's request while for others, I have upgraded the ATS to a 30 amp unit made by TRC.

Just be aware that if you have dual shore power inlets on your trailer that you WILL have the ATS and that it might be prone to failure.