Can my generator handle my AC unit?

[electron]

So I am looking at transfer switches, and I am trying to figure out if I should bother paying extra for another 220V circuit for my AC unit.

AC User Manual (PDF)

Pictures of all the AC hardware, and the generator:
http://mydotsoft.com/products/my.Gallery/?album=AC

Also, if you have any good suggestions on which transfer switch to get, don't hesitate to share. Thanks!

 

[Michael McSharry]

So I am looking at transfer switches, and I am trying to figure out if I should bother paying extra for another 220V circuit for my AC unit.

AC User Manual (PDF)

Pictures of all the AC hardware, and the generator:
http://mydotsoft.com/products/my.Gallery/?album=AC

Also, if you have any good suggestions on which transfer switch to get, don't hesitate to share. Thanks!

The inrush current is usually the killer for A/C or heat pump. I doubt if a standard generator can deal with the startup current necessary to start the A/C. Once it is going there will be problem. There may be "easy start" devices that can store sufficient energy to start the A/C, but I'm familiar with any in particular.

 

[upstatemike]

I guess my thinking would be that if it will not trip a 30 amp breaker on startup (6600 watts) then the 7350 startup watt rating of the generator should cover it. Of course you need to have absolutely nothing else connected to the generator at the time this thing kicks on so maybe not so practical.

After the Labor Day storm a few years back I got a generator and quickly realized I would have a similiar problem when the well pump started. Turns out the cheapest solution was to get a second generator that I could dedicate to the well. (also serves as a backup in case the first one won't start... I got real serious about backup power after that storm!)

 

[CollinR]

I was smack dab in the middle of the OK ice storm back in Jan, I went 30 days without power.


If you are for real about this you need to get a natural gas generator... I didn't have enough power to run my furnace but I couldn't afford to run the damn thing 24/7 anyway. Mine goes through about a gallon of gas per hour, the load doesn't seem to have a huge effect on it. What I wound up doing in reality was fire it up for several hours in the morning and charge everything that had a charger. Because the ice broke all the trees I had no firewood troubles, unfortunately the house I was in had no fireplace. 100% electric house so I was fawked.

I have since moved back to Tulsa, now I have gas furnace and gas fireplace. All I need is like 10-15amps of 110 to run the actual fan to circulate it.

 

[electron]

Natural gas generator is on my wishlist I have a natural gas furnace, so I don't think running that on the genny will be a problem, since the HVAC fan should be the only major current draw. I think I am just going to skip the AC all together, and use a backup window AC unit if something does happen while it is hot outside.

 

[gcimmino]

Natural gas generator is on my wishlist

I've been drooling for a natural gas powered generator for years. The wife started a business out of the home last year and we may soon have a "reason" to get one. Seems like every major storm a tree takes out power in the 'hood.

Anyone have any specific experience with these?

 

[AnotherOne]

Natural gas generator is on my wishlist

I've been drooling for a natural gas powered generator for years. The wife started a business out of the home last year and we may soon have a "reason" to get one. Seems like every major storm a tree takes out power in the 'hood.

Anyone have any specific experience with these?

I have a generac natural gas generator and it's been great. Had it for 8 years now and have abour 400 hours on it (probably 100 of those hours are the run once a week for 15 minutes test). Had to replace the battery twice, but that's about it. I have it serviced (oil change, cleaned, checked for mice eating wiring, etc) every 16 monhts. We had a terrible storm last winter and lost power for 8 days. We just ran the generator from 9am to 11am and invited the neighbors over to watch football games, take showers and stay warm.

 

[Rick_G]

Hello-

I'm a newb here but, I have a little experience with electric motors.

In the picture you provided it shows the compressor having a LRA (Locked Rotor Amperage) of 91 amps I believe that is the starting current on single phase motors.

91 amps x 230 volts = 20930 watts to properly start this motor.
91 amps x 200 volts = 18200 watts to properly start this motor.

I would say no, ymmv

Rick

 

[electron]

wow, definitely a no go then, thanks for posting!

 

[WayneW]

In the picture you provided it shows the compressor having a LRA (Locked Rotor Amperage) of 91 amps I believe that is the starting current on single phase motors.

91 amps x 230 volts = 20930 watts to properly start this motor.
91 amps x 200 volts = 18200 watts to properly start this motor.

I would say no, ymmv

I am not saying you are wrong because I don't know. But I have never seen a 90 amp breaker on a residential AC unit. How long does the starting current last? If the starting current doesn't trip a XX amp circuit breaker, does that equate to a XX amp peak load from a generator?

 

[DavidL]

http://ths.gardenweb.com/forums/load/wirin...0060723730.html
pretty much the same discussion with almost exact same specs.

 

[CollinR]

You can convert gasoline generators to natural gas without much trouble.

 

[upstatemike]

[/quote]
I have a generac natural gas generator and it's been great. Had it for 8 years now and have abour 400 hours on it (probably 100 of those hours are the run once a week for 15 minutes test). Had to replace the battery twice, but that's about it. I have it serviced (oil change, cleaned, checked for mice eating wiring, etc) every 16 monhts. We had a terrible storm last winter and lost power for 8 days. We just ran the generator from 9am to 11am and invited the neighbors over to watch football games, take showers and stay warm.
[/quote]

You only ran the generator 2 hours per day? I thought the point of natural gas "auto starting" generators was to provide power through the full duration of an outage?

 

[deranged]

I have done some work with electrical motors, before I found it it was much easier to deal with computers..
( now I am not so sure... )

Anway, LRA ratings are generally for a stalled motor, one that cannot turn for some reason. So you have to use that as a rule of thumb for starting current, as the compressor when starting may reach the LRA rating. Especially during a low voltage situation, or a unexpected start. A/C compressors must have a certain off time between cycles.

The startup current is so short, usually in milliseconds, and circuit breakers are very slow to respond, sometimes in seconds, so the breakers do not normally trip with the startup current.
Then you add in starting capacitors, hardstart capacitors, phase problems, frequency problems and it becomes a real mess.

My suggestion would be to email one of the generator manufacturers, as they would know thier equipment the best.
You might even be able to get info from the A/C manaufacturer.

StevenE

 

[Rick_G]

Hello-

I just googled "nec LRA single phase motors" this is the first hit http://www.generators.smps.us/sizing.html Does a good job of explaining what's happening.

Rick