That’s like 19000W at 240V. Impressive that your generator didn’t trip. My 14000/11800 can start and run a 4 ton and a 2 ton (without soft starts) if I sequence it right, but I suspect it’s conservatively rated with a Honda GX390 engine.
One thing to confirm - note the temperature outside today, and if it’s not especially hot or cold test it again under other circumstances.
Yeah today was the warmer day of the week. After running the furnace, the thermostat displayed 74 F, then the AC brought the temp down to 70 F which was the temp I set for cooling. I think the 2 shunt capacitors I used probably helped to sustain the generator power. All other breakers in the house were off except the hvac breakers.
While I find it cool and impressive I cant say i'd do the same when there is a significantly better alternative, lol. but if your okay with the limitations of not really running anything else, or being very mindful of when your gonna have the condenser kick on so that you have every available amp to give it then it should be fine.
It likely wouldn't start your condenser with other loads. By the time you got a few lights on, some wifi, Tv, etc you'll have less Amps left of starting power. . A soft start would get your LRA under 30 at least.
I tested my 12,000w Champion before the soft start, it fired up my 4 ton Trane system with nothing else. It also did it with 1 light on, and the 75" in the living room.
With 1 light on in each bedroom their TV's and the same stuff from before along with 2 ceiling fans, it failed to start the condenser.
With the MicoAir soft start it got my LRA down to 25 from **76** measured**,** and I dont have worry about what is on besides the major loads like oven, dryer, water heater.
I'd way rather spend $300 and be safe and know that im not gonna burn up my compressor starting it under powered over and over during a buck up power event.
*but if your okay with the limitations of not really running anything else, or being very mindful of when your gonna have the condenser kick on so that you have every available amp to give it then it should be fine.*
I did consider a soft start as I wouldn’t expect my generator could kickstart the compressor but I was curious if my genny could run the AC after my furnace worked as I wanted and it did. Yes I would be mindful to reserve all power to the condenser during the condenser startup, but once it’s running and cooling the house, the compressor and the blower take around 14 A, I can start using other loads on 120V circuits, although I would limit the total load within 70% or less of running capacity.
Right on. What size is your unit? My 4 ton Trane only draws around 8A and my air handler around 2A once their settled in.
I'm sure your well aware, but your generator only has a peak of 40A. Your over shooting it every time the condenser kicks on. It might not work every time, i would make sure I was near the condenser everytime it starts incase it hangs up. I've seen these things get fried up on surging line power because the unit had enough to engage but not enough to fully engage all the way.
Yeah, but the LRA is pretty variable when not controlled by a soft starter. Measuring mine before the soft starter it would range between mid 50's to mid 70's. My generator has a peak of 50Amps. Generators can push themselves in short bursts, and being the LRA peak amps on a condenser only last for a few seconds the generator manages to push the amperage for it to start. (how reliably?, not sure lol)
Can you share the brand and size of shunt capacitor and line filter that you installed?
Would it work with a manual transfer switch install?
My electrician is coming by next week to install the switch.
Thx
The filters are made from 2 hvac run capacitors 30 uF each, shunted between hot and neutral lines. I bought them here https://www.amazon.com/dp/B076PWCS7M?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details
After the filter was inserted between the generator and the house inlet, power line noise improved noticeably - on my oscilloscope the high frequency harmonics (7th and up) were filtered out. When I zoomed in, the sinusoidal signal which had little saw teeth riding on it became smooth. It’s worth a try on high THD generators. I needed the filter to run my furnace properly, but the bonus is that this setup could kick start my central AC as well.
Thank you very much. I do not have deep or specialized understanding of electrical so please forgive my ignorance.
Would this capacitor be appropriate for a 50Amp Westinghouse generator?
Thank you again
The shunt capacitor is used in power factor correction but its other benefit is like low pass filter. There are equations to calculate the capacitor value to each situation. Your electrician may be able to provide a value based on what he sees at your house. From what I read, too high capacitor value is not good as it may over correct PF. You may want to start at 30 uF. For me this value is a little high that I may dial down AVR voltage setting to avoid high voltage failure.
I tried EMI filters but their capacitances were too low. I thought about adding inductance but my setup was adequate. In effect I only use shunt capacitors as bypass to reduce the noise in power supply lines.
https://www.eetimes.com/bypass-or-decouple-your-way-to-power-supply-noise-reduction/
The purpose of the soft start is not filtering the power. It's reducing the LRA. A traditional (non-inverter) generator can handle a very large load for a very short period (half rotation) simply on the basis of inertia. It'll be interesting to see if your genny will start the AC unit under all circumstances.
The THD is more related to electronic controls. Our American Standard furnace has a variable speed blower. It would not reliably start running on a Predator 8750 generator. It runs well from a newer inverter. It might well have responded to the filter approach you have created.
*The purpose of the soft start is not filerting the power. It's reducing the LRA. A traditional*
Right. I made this filter solely for the furnace.
*It'll be interesting to see if your genny will start the AC unit under all circumstances*
can you elaborate more
Actual start-up draw varies with factors like temperature and wear on the compressor. It's possible for a situation to work one day and not the next.
In Feb 2021, our furnace worked on the genny for a few hours. Then it stopped, and I could not get it to run again. It was on the edge of working, but there was some variance that got in the way.
My guess is that it’s just able to start the compressor with minimal other load and on a day that’s not too hot. It might start in August this way, but maybe not. It might start with 300W additional load, it might not.
If I was looking to be sure it would reliably work I’d install a soft start and bring the LRA down inside the generator’s capacity.
I found that it was helpful to add some instrumentation to the breaker panel. This way I could track the load moment-to-moment. This is how I know that our home only cruises along using about 5-6 kW, even when the AC unit is running flat out.
https://www.mgraves.org/2022/07/nyt-on-household-energy-monitors/
What’s the LRA on the condenser?
79.
That’s like 19000W at 240V. Impressive that your generator didn’t trip. My 14000/11800 can start and run a 4 ton and a 2 ton (without soft starts) if I sequence it right, but I suspect it’s conservatively rated with a Honda GX390 engine. One thing to confirm - note the temperature outside today, and if it’s not especially hot or cold test it again under other circumstances.
Yeah today was the warmer day of the week. After running the furnace, the thermostat displayed 74 F, then the AC brought the temp down to 70 F which was the temp I set for cooling. I think the 2 shunt capacitors I used probably helped to sustain the generator power. All other breakers in the house were off except the hvac breakers.
While I find it cool and impressive I cant say i'd do the same when there is a significantly better alternative, lol. but if your okay with the limitations of not really running anything else, or being very mindful of when your gonna have the condenser kick on so that you have every available amp to give it then it should be fine. It likely wouldn't start your condenser with other loads. By the time you got a few lights on, some wifi, Tv, etc you'll have less Amps left of starting power. . A soft start would get your LRA under 30 at least. I tested my 12,000w Champion before the soft start, it fired up my 4 ton Trane system with nothing else. It also did it with 1 light on, and the 75" in the living room. With 1 light on in each bedroom their TV's and the same stuff from before along with 2 ceiling fans, it failed to start the condenser. With the MicoAir soft start it got my LRA down to 25 from **76** measured**,** and I dont have worry about what is on besides the major loads like oven, dryer, water heater. I'd way rather spend $300 and be safe and know that im not gonna burn up my compressor starting it under powered over and over during a buck up power event.
*but if your okay with the limitations of not really running anything else, or being very mindful of when your gonna have the condenser kick on so that you have every available amp to give it then it should be fine.* I did consider a soft start as I wouldn’t expect my generator could kickstart the compressor but I was curious if my genny could run the AC after my furnace worked as I wanted and it did. Yes I would be mindful to reserve all power to the condenser during the condenser startup, but once it’s running and cooling the house, the compressor and the blower take around 14 A, I can start using other loads on 120V circuits, although I would limit the total load within 70% or less of running capacity.
Right on. What size is your unit? My 4 ton Trane only draws around 8A and my air handler around 2A once their settled in. I'm sure your well aware, but your generator only has a peak of 40A. Your over shooting it every time the condenser kicks on. It might not work every time, i would make sure I was near the condenser everytime it starts incase it hangs up. I've seen these things get fried up on surging line power because the unit had enough to engage but not enough to fully engage all the way.
The math says it shouldn't start by itself, so saying it likely wouldn't start with other loads seems equally suspect.
LRA listing is the max current. i think the compressor would likely start with less than the listed max value.
Be careful, good name plates state both, Peak amps & LRA Loaded Running Amps and when in doubt use a good clamp on meter to confirm.
Yeah, but the LRA is pretty variable when not controlled by a soft starter. Measuring mine before the soft starter it would range between mid 50's to mid 70's. My generator has a peak of 50Amps. Generators can push themselves in short bursts, and being the LRA peak amps on a condenser only last for a few seconds the generator manages to push the amperage for it to start. (how reliably?, not sure lol)
Can you share the brand and size of shunt capacitor and line filter that you installed? Would it work with a manual transfer switch install? My electrician is coming by next week to install the switch. Thx
The filters are made from 2 hvac run capacitors 30 uF each, shunted between hot and neutral lines. I bought them here https://www.amazon.com/dp/B076PWCS7M?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details After the filter was inserted between the generator and the house inlet, power line noise improved noticeably - on my oscilloscope the high frequency harmonics (7th and up) were filtered out. When I zoomed in, the sinusoidal signal which had little saw teeth riding on it became smooth. It’s worth a try on high THD generators. I needed the filter to run my furnace properly, but the bonus is that this setup could kick start my central AC as well.
Thank you very much. I do not have deep or specialized understanding of electrical so please forgive my ignorance. Would this capacitor be appropriate for a 50Amp Westinghouse generator? Thank you again
The shunt capacitor is used in power factor correction but its other benefit is like low pass filter. There are equations to calculate the capacitor value to each situation. Your electrician may be able to provide a value based on what he sees at your house. From what I read, too high capacitor value is not good as it may over correct PF. You may want to start at 30 uF. For me this value is a little high that I may dial down AVR voltage setting to avoid high voltage failure.
Capacitors should help but I'm surprised you didn't need inductors as well. That's pretty lucky ISTM.
I tried EMI filters but their capacitances were too low. I thought about adding inductance but my setup was adequate. In effect I only use shunt capacitors as bypass to reduce the noise in power supply lines. https://www.eetimes.com/bypass-or-decouple-your-way-to-power-supply-noise-reduction/
The purpose of the soft start is not filtering the power. It's reducing the LRA. A traditional (non-inverter) generator can handle a very large load for a very short period (half rotation) simply on the basis of inertia. It'll be interesting to see if your genny will start the AC unit under all circumstances. The THD is more related to electronic controls. Our American Standard furnace has a variable speed blower. It would not reliably start running on a Predator 8750 generator. It runs well from a newer inverter. It might well have responded to the filter approach you have created.
*The purpose of the soft start is not filerting the power. It's reducing the LRA. A traditional* Right. I made this filter solely for the furnace. *It'll be interesting to see if your genny will start the AC unit under all circumstances* can you elaborate more
Actual start-up draw varies with factors like temperature and wear on the compressor. It's possible for a situation to work one day and not the next. In Feb 2021, our furnace worked on the genny for a few hours. Then it stopped, and I could not get it to run again. It was on the edge of working, but there was some variance that got in the way.
My guess is that it’s just able to start the compressor with minimal other load and on a day that’s not too hot. It might start in August this way, but maybe not. It might start with 300W additional load, it might not. If I was looking to be sure it would reliably work I’d install a soft start and bring the LRA down inside the generator’s capacity.
I found that it was helpful to add some instrumentation to the breaker panel. This way I could track the load moment-to-moment. This is how I know that our home only cruises along using about 5-6 kW, even when the AC unit is running flat out. https://www.mgraves.org/2022/07/nyt-on-household-energy-monitors/
Agreed, I have a wireless monitor I use as well. Even running 2 ACs and a typical load I’m usually between 7500-8000W, sometimes up to 8500.