Added a few gadgets over the past few weeks (Page 1/1)
CoolBlue87GT NOV 04, 01:57 AM
I added a few gadgets over the past few weeks.

First one is a soft start for the home AC. It took the starting Amps from 132 down to 24 starting amps. That's 108 less amps !



It starts the fan first, then starts the compressor. The starting sound used to be very loud, now it's very quiet.

Here's a sample of the sound now.


I picked up a new Generator, Predator 9500. (9500 starting watts & 7600 running watts) It should run most of the house, including the AC in the event of a power outage. It's just as quiet as my Honda's that are only 2200 watts. Those got me through 2 major hurricanes & countless power outages over the years.



I plan to install interlock & generator hook up socket to eliminate running extension all over the place.

[This message has been edited by CoolBlue87GT (edited 11-05-2025).]

Patrick NOV 04, 03:18 PM

quote
Originally posted by CoolBlue87GT:

First one is a soft start for the home AC. It took the starting Amps from 132 down to 24 starting amps. That's 108 less amps !
It starts the fan first, then starts the compressor. The starting sound used to be very loud, now it's very quite.



So it appears that the fan draws 24 amps when it starts. Just curious... what is the additional starting amp draw then when the compressor kicks in? 108? If so, is there actually any power saving?

[This message has been edited by Patrick (edited 11-05-2025).]

CoolBlue87GT NOV 04, 10:35 PM

quote
Originally posted by Patrick:

So it appears that the fan draws 24 amps when it starts. Just curious... what is the additional starting amp draw then when the compressor kicks in? 108? If so, is there actually any power saving?



I believe the 24 amps (Last Start Peak amps) was both the fan & compressor. I don't see how the fan alone could pull that many amps, it's rated at 3.5 amps.

Follow are the rating w/o the soft start.
The fan FRA is 3.5 amps
Compressor RIA is 17.0 amps
Compressor LRA 123.9 amps

Your question about power savings, once the unit has started, the running amps are most likely the same. The "savings" most would say would come from making the unit last longer by not hitting it with the 123.9 start up amps.

I will talk with the tech support guy tomorrow and ask if the 24 amp reading includes the fan & compressor. Will update you later when I find out.

[This message has been edited by CoolBlue87GT (edited 11-04-2025).]

Patrick NOV 05, 12:29 AM

quote
Originally posted by CoolBlue87GT:

I will talk with the tech support guy tomorrow and ask if the 24 amp reading includes the fan & compressor. Will update you later when I find out.



Thanks. Technically speaking, I'm just curious what the actual benefit of that device is. Yeah, see what the tech guy says.

[This message has been edited by Patrick (edited 11-05-2025).]

CoolBlue87GT NOV 05, 10:03 AM
Here what I found.

The soft start can make a compressor last longer by reducing the initial stress and electrical surges during startup. It does this by gradually increasing the power to the compressor instead of delivering a sudden, hard jolt of electricity, which minimizes wear and tear on the compressor and other components.

A 24-amp startup reading for a Trane AC compressor with a soft start added is likely normal and an expected outcome of using the device.
Soft starters are designed to significantly reduce the high inrush current (locked rotor amps, or LRA) that compressors typically draw on startup, which can often be 3 to 6 times their normal running load amps (RLA). The 24-amp reading indicates a successful reduction from a much higher potential LRA.

Here are some context points to consider:
Typical Reduction: Soft starters can reduce startup amperage by 55% to 75%. For example, one user reported their 4-ton unit's startup amps dropped from 76 amps to 24 amps after installing a soft start.

Running Amps: A typical central AC unit has running amps (RLA) between 15 to 45 amps, depending on its size (tonnage). A 24-amp startup reading is often close to or slightly above the unit's normal running amperage, which is the goal of a soft start.

[This message has been edited by CoolBlue87GT (edited 11-05-2025).]

Patrick NOV 05, 02:50 PM

quote
Originally posted by CoolBlue87GT:

Here what I found...



Interesting. So there's a lot more to what this device does then than simply stagger when the fan and compressor come on.

I'm surprised that an electric motor will actually start rotating if its usual starting amp draw has been forcibly reduced. I would've thought it would just sit there and hum!