Generator Switch Box

[Darrell Snell]

(03-02-2013 11:27)davidmbrady Wrote:  Darrell,

The installation manual specs locked compressor inrush at 60A and locked fan motor at 6A. I don't think there's any delay built in to delay compressor startup. I believe this cause there are addons to dometics to insert delays. What are your leg voltages during compressor startup? If the genny is a weak voltage source then voltage will fall more than normal and inrush current will increase above those spec-ed in the manual. I think max inrush would occur only for the first half second or so and quickly disappear and be over within 3s (exponential decay). I have had no problems running three AC's on the genny. The manual specs a minimum generator capacity of 3.5KW per AC unit, so our 15KW units are easily adequate if operating normally.

http://www.dometic.com/1f24ead8-6316-41b...6bad.fodoc

Dave
Had a look at AC voltage today with shore power and genny.
SP has 125v no load, and 116~v when 1 compressor kicks in.
Genny shows 120v and 119v when 1 compressor kicks in.

I have an extension cord 100' long with #8 wire so I think this is part of the problem with voltage drop. It hasn't concerned me since I won't be using this arrangement once my permanent AC connection is in place in a couple of weeks (before air conditioning season).

But the problem with high starting current still occurs with genny power.
If I turn on the forward AC switch and create a demand at the thermostat all will work well. The fan will come on and a short time later the compressor will pull in with a quick spike. But if I should turn off the forward AC switch while there is a demand and turn it on again there is a prolonged spike of about 10 secs + that is kinda scary. This happens on all units.
I plan on contacting Dometic to see what gives with delays as it seems they have one for one condition but not one for an equally important condition.
D