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menoble · 07-21-2013, 06:19 AM

Running my A/C with tandem EU2000's in ECO mode hasn't always been successful, so a hard-start capacitor kit is on the way. Looks like the OEM is making it easy for me, only two wires and the anchor strap has few extra holes in it for a fatter capacitor. Still wish there was some way to automatically give the gens a 2-3 second head start before throwing the load at them, but maybe this will be enough.

jesilvas · 07-21-2013, 07:58 AM

That does have a hard start on it.
How do you run the ac: auto fan or on all the time?

menoble · 07-21-2013, 08:33 AM

Quote:

Originally Posted by jesilvas

That does have a hard start on it.
How do you run the ac: auto fan or on all the time?

Yes, it has a standard start capacitor, I believe the kit's is about 2X the Mf what I have now.
With ECO on, I've had the best luck running the fan on manual and the compressor on auto. But the lights dim and fan pulls down as the compressor starts and the gens wind up. It's not a critical situation, but I feel like the hard starts accumulate over time, shortening the life of the motor windings. If it doesn't help and I toast the motor anyway, at least I won't kick myself for not trying!

Ray,IN · 07-21-2013, 03:29 PM

Don't attempt to power the A/C in ECO-mode. It's easier on your gensets and the A/C unit. Then you don't have to be concerned with a "head start" for your genset.

Stan.Birch · 07-21-2013, 03:57 PM

Does anyone have the specs for the actual current-demands for an A/C??

So . . . locked-rotor runs around 50 amps or so, which I presume represents max current demand on a really hot day, a couple minutes right after the A/C
has been shut off. That's similar to starting an air compressor when the reservoir is already at 110 PSI; but when the compressor is first started at 0 PSI, the startup current is insignificant.

I suspect that same is true for an A/C. If the A/C is started up after a long rest, then the startup current should be nominal. ?? So . . . if you only start the A/C after a long rest, with nominal startup current, then even a 2000w generator should be able to handle an A/C as long as you keep the A/C running continuously after startup. ??

Anyone know:

1. Startup current for an A/C that has been resting??

2. Startup current with a hard start cap, for an A/C that has been:
(a) resting, or
(b) that was running only a couple minutes ago??

jesilvas · 07-21-2013, 04:18 PM

There are LRA and other ratings on the AC unit itself.

menoble · 07-21-2013, 04:22 PM

Quote:

Originally Posted by Ray,IN

Don't attempt to power the A/C in ECO-mode. It's easier on your gensets and the A/C unit. Then you don't have to be concerned with a "head start" for your genset.

The gens cruise along quietly and efficiently on ECO, except for the brief seconds it takes to start the A/C every few minutes. If a $20 part will take care of those, I'm a happy camper.

menoble · 07-21-2013, 04:27 PM

Quote:

Originally Posted by jesilvas

There are LRA and other ratings on the AC unit itself.

Such as:

jesilvas · 07-21-2013, 04:48 PM

Quote:

Originally Posted by Stan.Birch

Does anyone have the specs for the actual current-demands for an A/C??

Compressor is 10.4A once running. Fan is 3.4 once running.

So . . . locked-rotor runs around 50 amps 54A or so, which I presume represents max current demand on a really hot day, a couple minutes right after the A/C
has been shut off. That's similar to starting an air compressor when the reservoir is already at 110 PSI; but when the compressor is first started at 0 PSI, the startup current is insignificant.

The issue with your analogy is that the AC system always has pressure on it, it is never 0PSI. What changes is that after resting for 3-5 mins (current thermostats force the compressor to delay anyway) the pressure pre and post compressor is pretty equal, whereas immediately after shutdown, the pressures are not equal.

I suspect that same is true for an A/C. If the A/C is started up after a long rest, then the startup current should be nominal. It should be 54A for the compressor. ?? So . . . if you only start the A/C after a long rest, with nominal startup current, then even a 2000w generator should be able to handle an A/C as long as you keep the A/C running continuously after startup. ??

Anyone know:

1. Startup current for an A/C that has been resting??

LRA of 54A.

2. Startup current with a hard start cap, for an A/C that has been:
(a) resting, or
(b) that was running only a couple minutes ago??

I'm not sure what else you're wanting or I just don't understand.
A PTCR just helps it start easier because the compressor is allowed to receive more power than it would have before.

Stan.Birch · 07-22-2013, 06:43 AM

Quote:

Originally Posted by jesilvas

The issue with your analogy is that the AC system always has pressure on it, it is never 0PSI. What changes is that after resting for 3-5 mins (current thermostats force the compressor to delay anyway) the pressure pre and post compressor is pretty equal, whereas immediately after shutdown, the pressures are not equal.

A PTCR just helps it start easier because the compressor is allowed to receive more power than it would have before.

Thanks. That makes sense.

Ray,IN · 07-22-2013, 02:14 PM

Quote:

Originally Posted by menoble

The gens cruise along quietly and efficiently on ECO, except for the brief seconds it takes to start the A/C every few minutes. If a $20 part will take care of those, I'm a happy camper.

It's your money and equipment to do with as you please. I stand by my statement, and this article agrees. It's that "few seconds" that spells future problems with your genset and A/C unit.

menoble · 07-22-2013, 02:55 PM

Quote:

Originally Posted by Ray,IN

It's your money and equipment to do with as you please. I stand by my statement, and this article agrees. It's that "few seconds" that spells future problems with your genset and A/C unit.

Thanks for the information, that's relative to my earlier comment that I wish there was some kind of data link between the A/C and the generators to spin them up 2-3 seconds before startup. I understand the problems repeated brown starts can cause.