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Tom 1957 08-01-2022 11:37 AM

Generator Questions
 
Howdy folks!


I have questions about generator use with my Keystone Cougar Half Ton 28SGS and a NorthStarô 5500 open frame generator converted to run on gas, propane, or natural gas. (I understand that when powering the generator off of propane, that my output is a bit less than with gasoline, but trying to see if that's enough generator to power the RV).



Generator is 5500 watts peak and 4500 watts when running on gasoline. It accepts a a NEMA L14-30P 30 AMP twist lock male plug. My adapter has that on one end and a NEMA 14-50R female on the other end that connects to the RV 50 AMP plug. The 12 inch long adapter cables (4) are STW 10 AWG. I did a continuity test to verify all four conductors are consistent.



When running off of this generator, are both 120 VAC legs of the 50 AMP service to the RV receiving 2,750 surge watts and 2,250 running watts, 22.91 AMPS and 18.75 AMPS respectively? Do they load balance at all?


Of course I'll have lower output when running on propane.



I'm about to install two Micro-Air ASY-364-X36-BLUE EasyStartô Soft Starters on the main room 15K BTU Dometicô BriskII AC and bedroom 13.5K BTU Dometicô BriskII AC units to help reduce the inrush current required to start either or both AC units simultaneously when running off of the above generator. (AC units are on separate legs of the 120 VAC service).



Thank you in advance for sharing your technical expert advice.



Tom

flybouy 08-01-2022 12:24 PM

The 30 amp plug you cite is a 4 conductor 220 v plug. I would consult the literature that came with the generator as to how the 30 amps I'd distributed. Is the circuit breaker on the generator a 2 pole breaker, i.e. two 30 amp breakers mechanically connected so that if one trips they both trip?

bsmith0404 08-01-2022 12:32 PM

Itíll probably work the way youíre doing it, however you will be close on power and may find there are times itís not enough or you may need to shut down some items such as the converter. When you switch to LP, you will lose quite a bit, I doubt itíll be enough to run both ACs even with the soft start. My understanding from dealing with factory reps and from other discussions weíve had on this forum is your converter will need about 7 amps. When you factor that in with the loss of output with LP, I donít think itíll be enough.

Canonman 08-01-2022 12:48 PM

Short answer to your question is both legs will be hot at 120v. That said, they will "share" the total 18.75 running amps. No load balancing. If one leg is pulling 15 amps (your main A/C) there are still only 3.75 amps left to share between the two legs.
Add up the amp load from both A/Cs and your over the running output for this generator.
1725 watts Main A/C + 1300 watts bedroom A/C = 3025 watts or 25 amps. This does not take into account the start up power requirements.
So, I'm pretty sure you'll be a bit short on power for both AC's if that's your plan.
Plus, that open frame generator is really noisy (73db) compared to an inverter type.

bsmith0404 08-01-2022 01:15 PM

Quote:

Originally Posted by Canonman (Post 511617)
Short answer to your question is both legs will be hot at 120v. That said, they will "share" the total 18.75 running amps. No load balancing. If one leg is pulling 15 amps (your main A/C) there are still only 3.75 amps left to share between the two legs.
Add up the amp load from both A/Cs and your over the running output for this generator.
1725 watts Main A/C + 1300 watts bedroom A/C = 3025 watts or 25 amps. This does not take into account the start up power requirements.
So, I'm pretty sure you'll be a bit short on power for both AC's if that's your plan.
Plus, that open frame generator is really noisy (73db) compared to an inverter type.

Iím a little confused on his available power. Iím not sure how itís getting split to 22 amps on one leg and 18 on the other. His 4500 watt running power should be providing 37.5 amps constant power. I would have thought if it split in the plugs that it would be roughly 19 amps per leg. Iíve never tried or used a setup the way the OP has it, so I was just going off what he said he had for available power.

Canonman 08-01-2022 01:35 PM

You're right. I misread the original post. 4500 watts would mean 37.5 amps. But he only has a 30 amp plug and I would guess a 30 amp breaker providing 3600 watts. Still not much headroom if he's using 3000 watts for the 2, A/Cs.
Apologizes for the mistake.


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