Hughes Autoformer & EMS Surge Guard

[H. John Kohl]

This came from another topic. I am posting here to prevent hijacking the original topic.

quote:Originally posted by exav8tr

I put the EMS first, then the Autoformer and the power cuts out. Seems like this should work as others have done it, Bingo, I believe is one.....When I use them seperately they work fine......

Phil,
Your problem brings up some interesting questions.
1. There have been many discussions about the placement of the autoformer before or after the surge protector.
- Have you tried powering your trailer with the autoformer connected to the power pedistal, hughes, surger protector and then Monty?

2. Have you contacted both Hughes and EMS about this problem?
- My limited mind thinks the EMS does not like connecting to a transformer instead of the main trailer. Do you remember what error code the surge protector gives you when the autoformer is plugged in between the surge protector and Monty?

[Tom S.]

I think the problem is the order in which he is connecting them. If he connects the Autoformer first, it should work fine. The AC that comes out of any electrical outlet has been stepped up and down by transformers, so the transformer in the Autoformer shouldn't cause any problems with the EMS if it's in line before the EMS. Putting it in line after the EMS may be causing an issue due to how the Autoformer is grounded.

[H. John Kohl]

Tom S.,
Your comment is along the same lines as I was thinkg. Thanks for the proper words.

[exav8tr]

I will experiment with this either today or tomorrow. Thanks for moving topic and for the advice.

[Exnavydiver]

Ok, here is one other idea, if you put the autoformer after the EMS then how is it supposed to do any good? If the voltage goes low enough that the autoformer is needed the EMS will shut down the system. Same for high voltage. I Believe that the autoformer has to go first, then the EMS. JMHO...Dave P.S. Actually the more I think about it the more I think that it should be just the EMS until it finds a low voltage situation then put the autoformer between the EMS and pedestal. Since the EMS is there to prevent both low and high voltage episodes from hitting the rig. The autoformer is to remedy a low voltage situation. If you have a low voltage situation and you can't change campsites or camp grounds then use the autoformer to bring voltage back to usable levels so you can have power to the rig, at that point you should be able to use the EMS again...

[8.1al]

Good points Dave. If you put the EMS first it will cut out under low voltage and you won't get the benefit of the Autoformer. I used to always use both and had continuing problems with high voltage. I found out that the autoformer is still boosting 2% even when the voltage is high, so if the park voltage is on the high side and then you boost it, well you'll be wondering where your power went. Now I do as Dave suggested, I use the EMS and if conditions warrant I throw the Autoformer out.

[NCFischers]

The autoformer will boost the power 10% when voltage drops to 116 and 2% when it hits 118. This equates to 127.6 volts and 120.7 volts respectively. The surge guard works in the range of 102 to 132 volts, well outside the parameters of the autoformer. I couldn't find spec's on surge cut out voltage on the autoformer. Maybe someone can help me here. The manufacturers recommend that the autoformer be placed first in line but according to these numbers, the surge protector will not shut down before the autoformer will kick in. Grounding shouldn't be a problem since both units are grounded through the fourth wire back to the pedestal.

[exav8tr]

Thanks again, I did not have time to try anything today, Lazy days of fall you know......Will put the autoformer first, then the EMS. When I plug in the EMS, I always seem to get good voltage, but once a load is placed on it, it usually goes down somewhat. Is this normal???? I could live with one or the other, but would prefer to have the EMS system on line most of the time....Can use autoformer when needed.......Sounds like a plan.....

[ken]

Thats strange. I was told that the 30 amp autoformer has a surge protector built in. This was told to me by a Hughs technician at one of the rallys we went to. We bought the Model RV2130 and the brochure states that it will suppress spikes and surges, preventing damage to your electrical system.

[bncinwv]

Ken,
That is correct to an extent. The autoformer is equipped with a lower joule rating surge suppression. Seems like somewhere around 7200 joules. The EMS is rated for substantially more.
Others,
The previous posts regarding a boost of high power are correct. I have had instances where the Autoformer will boost above the EMS resulting in power shut down to the rig. The boost was confirmed with voltage meter readings in the rig that approached red-line (130-132 volts). My autoformer (for those who recall) is configured where I can take it out of the loop in the battery compartment (loop being autoformer, Iota smartswitch and EMS - autoformer first) if needed. I have had to do this a couple times to rememdy the EMS cutting off power to the rig because of over voltages.
Bingo