Generators and computers

[Lucid Moments]

I have my home networking equipment, including my Starlink internet, on a UPS. When I lose power the UPS will run the network for about 45 minutes which is great. But for some reason the UPS does not like the power from my generator so once it is done it is done until grid power comes back. This is rarely an issue for me so I am not willing to spend much money to fix it, but am curious if there is a relatively cheap fix to condition the power from my generator at this one outlet.

 

[RPH]

The power from the generator is dirty in the sense it has noise. Most cheaper generators are not sine wave units. But use a modified square wave output. There are many products that won’t run on them. Short of getting a true sine inverter product, you’re going to find nothing cheap. Figure a $1000, more or less to get some functional. How much time that buys you depends on which way you go.

 

[MongoTA]

"Inexpensive", my brother (software engineer) picked up a couple of ~$125 power conditioners for his place in Maine. He said he got them via Amazon. I have an inverter generator for my house so I never asked questions about how well they work.

 

[dcg9381]

I have my home networking equipment, including my Starlink internet, on a UPS. When I lose power the UPS will run the network for about 45 minutes which is great. But for some reason the UPS does not like the power from my generator so once it is done it is done until grid power comes back. This is rarely an issue for me so I am not willing to spend much money to fix it, but am curious if there is a relatively cheap fix to condition the power from my generator at this one outlet.

Interesting. UPS are notoriously particular about input power. Have you looked at the actual signal from your genset on a scope? It could just be that it needs frequency (RPM) adjustment. A "power conditioner" in front of the UPS might work.

It might be as simple as a different UPS. I'm running 5 different UPS' currently. They're happy with the generator power out of a 20Kw Generac unit... We never lose internet or POE power even for a second... Often I don't even know until the generator kicks on.

 

[rlitman]

The power from the generator is dirty in the sense it has noise. Most cheaper generators are...

I don't recall the last time I've seen a square wave inverter generator. Cheap UPS, sure, but all the Chonda knockoffs are true sine wave, and won't have the issue the OP is describing.

Lucid, what sort of generator do you have? That makes SOME difference. But one thing to consider is that most noise on your system comes from your connected equipment, and not from the generator itself. The thing is that on utility, that noise reflects back out your service to the utility transformer. When you're on generator, the noise reflects back to the generator. The best analogy I can give is it's like farting in a phone booth, vs in a stadium.

So, the first thing I'd try is to turn off EVERYTHING else and see if the UPS is happy to run on your generator's power without any other loads.

Knowing what type of generator you have, and if it produces clean enough power for the UPS (the above test), is critical to know before I can give you any more relevant advice.

 

[FJ 432]

I sell generators. You need an inverter style generator which produces clean power. As others have mentioned some generators put out noisy power which is fine for running power tools at a construction site. Inverter gens are quiet and put out less nosie.

 

[The Cobbler]

not to derail this thread, but I have a very cheap inverter generator from Walmart. it was under $200 and rated for 1,000 watts. I've often wondered if it puts out clean power .

 

[rlitman]

not to derail this thread, but I have a very cheap inverter generator from Walmart. it was under $200 and rated for 1,000 watts. I've often wondered if it puts out clean power .

So long as the power draw is within it's limits, I would expect the power to be incredibly clean, because sinewave inverters are effectively active power filters. But if you try to say start a circular saw on it, assuming it doesn't trip the overload, there is going to be an incredible amount of momentary noise.

 

[Lucid Moments]

My generator is from Harbor Freight. The Predator 9KW (starting) version, and I suspect that the power from it is pretty dirty. It does the main thing I need which is to power my well pump. Honestly my power is less of an issue than I thought it would be when I built this place in 2019. I have only needed the generator maybe 3 or 4 times in 5 years, but I do like being able to flush toilets without worrying about it.

As an alternative I have a group 31 battery that I ended up with. I mostly use it to power the winch on my trailer, but it lives on a battery maintainer in my shop. I may just buy a true sine wave inverter and bring it into the office for the network at need.

 

[Denwood]

We had issues with a generator for both the UPS units in my home, as well as the HVAC system which uses a communicating stat, ECM motors etc. Switching to an inverter/generator resolved all issues.

 

[RPH]

The pictures explain the modified sine wave versus our sine wave. The scope pictures shows the output wave forms that the device deals with. Computers, even the industrial grades are power sensitive.

 

[rlitman]

My generator is from Harbor Freight. The Predator 9KW (starting) version, and I suspect that the power from it is pretty dirty...

Ok, 3600 RPM synchronous. That shouldn't be too noisy harmonics wise for a UPS, but it might be if something is severely wrong with it. More likely, it could be running too fast or too slow frequency wise (UPS can get pretty picky about that), or possibly over or under voltage (better UPS deal with this using auto-transformers, but cheaper ones will fall over to battery). Do you have a multimeter that can check voltage? Better yet, one that can count frequency?

...
The pictures explain the modified sine wave versus our sine wave. The scope pictures shows the output wave forms that the device deals with. Computers, even the industrial grades are power sensitive.

Again, not relevant here.

 

[dcg9381]

Do you have a multimeter that can check voltage? Better yet, one that can count frequency?

Frequency being off or varying is my suspicion as well.

 

[Lucid Moments]

Ok, 3600 RPM synchronous. That shouldn't be too noisy harmonics wise for a UPS, but it might be if something is severely wrong with it. More likely, it could be running too fast or too slow frequency wise (UPS can get pretty picky about that), or possibly over or under voltage (better UPS deal with this using auto-transformers, but cheaper ones will fall over to battery). Do you have a multimeter that can check voltage? Better yet, one that can count frequency?

I do have a multi meter that can check voltage, I don't think it can do frequency but I bet I know someone that does.

 

[rlitman]

Frequency being off or varying is my suspicion as well.

If it is the problem, and the generator isn't hunting due to carb issues, getting the voltage and frequency into spec may just take some gentle screwdriver turning. But since this isn't computer controlled, you can expect the voltage and frequency to start out a little high on idle, and bog down a bit under load.

 

[Jsf721]

i have a UPS on my cameras, internet equipment and alarm and I don't expect to have that issue with my Generac 22KW whole house generator. I have never lost power for longer than the UPS covers.

 

[RPH]

Not my issue but I’ve seen distorted waveforms before and it can definitely affect the circuitry inside the backup. Do as you choose but it was stated to be aware of what the output of a generator. Clean power will come from a very good sine wave inverter.

 

[David Paul]

I had a UPS that would not work with my Honda generator that had AVR? Auto voltage regulator I believe. CyberPower makes an UPS that has a specific generator mode. Works like a charm with the same generator. I’ve since upgraded to Honda inverter style to head off any issue with new equipment, ie electronic controls in a new furnace.

 

[yatg]

UPS does not like the power from my generator

meaning what? it gives an error? it shuts down?

Maybe a double conversion aka online UPS will solve the problem.

Typical UPSs are line interactive, meaning they use line voltage when present then switch to battery when the voltage drops above/below its limits. Some conditioning is usually done on the incoming line voltage to regulate voltage to 120, but probably not hz.

In an online UPS, the line charges the battery, the battery powers the outputs. Considerably more expensive:

Amazon.com

And it could still not like the generator input power, if that's your issue.

Probably cheaper to get a decent generator.

 

[wyliesdiesels]

just buy an inverter generator. should solve the problem

 

[theoldwizard1]

The power from the generator is dirty in the sense it has noise.

That is a VERY BROAD statement !

Yes, some are, but I would say most ARE NOT ! Get a meter that measures THD or better yet, an oscilloscope.

But use a modified square wave output (and) there are many products that won’t run on them.

I have never heard of an engine powered generator that outputs a modified square wave ! I don't think it is possible !

 

[dogdog]

some people here are confused with Inverter generator, generator, and.... those dc-ac inverter outputs and that marketting ****

Pure Sine Wave​

https://www.sciencedirect.com/topics/engineering/sinusoidal-pulse-width-modulation

 

[theoldwizard1]

not to derail this thread, but I have a very cheap inverter generator from Walmart. it was under $200 and rated for 1,000 watts. I've often wondered if it puts out clean power .

Highly likely, YES !

Inverter generators make variable voltage and variable frequency AC voltage. It is immediately converted to high voltage DC. An inexpensive "chip" and some transistors make clean AC.

The cost difference between MSW and PSW is so low, I am surprised you can even buy a MSW inverter !

 

[Lucid Moments]

meaning what? it gives an error? it shuts down?

Maybe a double conversion aka online UPS will solve the problem.

Typical UPSs are line interactive, meaning they use line voltage when present then switch to battery when the voltage drops above/below its limits. Some conditioning is usually done on the incoming line voltage to regulate voltage to 120, but probably not hz.

In an online UPS, the line charges the battery, the battery powers the outputs. Considerably more expensive:

Amazon.com

And it could still not like the generator input power, if that's your issue.

Probably cheaper to get a decent generator.

Meaning that when I am on the generator the UPS doesn't recognize it. Powers what is plugged into it off the internal battery and will eventually run out of power.

A better generator isn't going to happen. It isn't a problem often enough to justify the expense.

 

[Lucid Moments]

just buy an inverter generator. should solve the problem

Again, not worth the expense. I haven't needed the generator but 4 times since I built my house 5 years ago. For that little bit I will just do without internet for a few hours.

 

[RPH]

Highly likely, YES !

Inverter generators make cariNle voltage and variable frequency AC voltage. It is immediately converted to high voltage DC. An inexpensive "chip" and some transistors make clean AC.

The cost difference between MSW and PSW is so low, iam surprised you can even buy a MSW inverter !

Little more involved than a “chip” and some transistors. I’ve dealt with all kinds of generators and inverters for 40 years. Takes more engineering than you indicate.

 

[theoldwizard1]

Little more involved than a “chip” and some transistors. I’ve dealt with all kinds of generators and inverters for 40 years. Takes more engineering than you indicate.

EGmicro EG8010 Single Phase Sinusoid Inverter ASIC
Several years old. Requires a MOSFET driver and as many MOSFETs as required to power the transformer to make the desire power.

EG8011. Next generation (already out for several years.) The ASIC and the driver are sold preassembled on a board called the EGS003.

Chinese schematic.

 

[theoldwizard1]

EGS002 (old version) Amazon $7.43

 

[theoldwizard1]

My generator is from Harbor Freight. The Predator 9KW (starting) version, and I suspect that the power from it is pretty dirty.

Probably not !

After watching dozens and dozens of James Condon YouTube videos (and a 50 year old EE degree), I have learned a couple of things.

The worst waveforms come from brushless generators. Probably because the DC created to power the rotor is not very clean. Brushed generators are usually pretty good (clean the contact rings helps a little.) He always load test the generators he fixes. Lately he has been posting "total harmonic distortion" (THD) and oscilloscope waveforms.

Just a SWAG. The UPS charging circuit might not have a "soft start" circuit built in. This means, as soon as it see "power" it wants to pull a extreme load to charge up capacitors, just for a split second. The voltage may sag and then the UPS says, "Nope, don't want that !"

No guarantee that an inverter generator will have the same problem. You just have to try it !

 

[theoldwizard1]

EGmicro EG8010 Single Phase Sinusoid Inverter ASIC

And they make a 3 phase ASIC also !

 

[RPH]

EGmicro EG8010 Single Phase Sinusoid Inverter ASIC
Several years old. Requires a MOSFET driver and as many MOSFETs as required to power the transformer to make the desire power.

EG8011. Next generation (already out for several years.) The ASIC and the driver are sold preassembled on a board called the EGS003.

Chinese schematic.

I will give you credit for trying. That schematic has a lot of missing connections to drive the circuitry. Many of the first tube welders used mosfets in parallel for current capacity. This module had forty large mosfets. Modules were then paralleled to increase overall power output. The distance between module one and the last module required the gating signals to be transmitted optically. It was the way to insure the modules all turned on and off at the same time. The length of the optic cable was the same for all modules. Shoot through is a real and distinct threat to any power transistor. It’s not just the potential that’s a concern but current controls. Back emf is destructive if not handled appropriately.
I will have to dig some board schematics for the things labeled pcb in most schematics. Lot more going on down deep that requires continuous overwatch. Even phase loop locked circuits are more complex then most envision.

 

[HotelMike]

Could it be a grounding issue? I’ve heard Tesla’s need ground and neutral to be bonded to charge.

 

[rlitman]

Could it be a grounding issue? I’ve heard Tesla’s need ground and neutral to be bonded to charge.

Ground testing circuitry is called for on EV charging, because the vehicle is sitting on tires. It's not something you would ever encounter on a UPS.

 

[alfredeneuman]

I’ve heard Tesla’s need ground and neutral to be bonded to charge.

Neutrals are all bonded at the main panels.

 

[Denwood]

Could it be a grounding issue? I’ve heard Tesla’s need ground and neutral to be bonded to charge.

You do need to either purchase or make a neutral to ground plug in order to get an EVSE to work with a typical inverter/generator. Our EV charges fine from the inverter/generator with a cable where ground/neutral is bridged. Have only tested with a 120V unit though.

 

[Denwood]

I do have a multi meter that can check voltage, I don't think it can do frequency but I bet I know someone that does.

Been there, done that. Tuned the old generator to nail down both voltage and frequency…it likely won’t work. The inverter/generator fixed the issues.

 

[MushCreek]

Several years ago, we had a bad storm and lost power for several days. I hooked up my Honda generator, and it worked fine, but as soon as I turned the microwave, it died with a loud 'POP' noise. I always wondered if the genny was to blame. It's a 5500 W Honda, and a very pricey rig, but it is fairly old. During this recent storm, it ran everything fine, but I didn't try the MW.

 

[rlitman]

Several years ago, we had a bad storm and lost power for several days. I hooked up my Honda generator, and it worked fine, but as soon as I turned the microwave, it died with a loud 'POP' noise. I always wondered if the genny was to blame. It's a 5500 W Honda, and a very pricey rig, but it is fairly old. During this recent storm, it ran everything fine, but I didn't try the MW.

There are two main types of microwaves on the market. The old style switches the magnetron on and off to control power output, and uses a single diode on the input (half wave rectifier), so it has a massively dirty current draw. And there's the newer style that's inverter powered, and that has the ability to control the magnetron power level without pulsing it. Even though inverter inputs themselves are fairly dirty (more modern designs are far less so), the diode design is about the absolute worst thing you can plug into a generator I can think of.

 

[MushCreek]

This was a Panasonic inverter-type MW, fairly new (4 years ago).

 

[rlitman]

This was a Panasonic inverter-type MW, fairly new (4 years ago).

Well that *****. At least the diode design is fairly bulletproof, and just won't work on generator. Though they're known to cause so much noise on generator that they can wreck other stuff like TVs. Inverters OTOH may make a little less noise, but they can also try real hard to accept incoming noise to the point of destruction. And the thing about generators is that no matter how clean the generator output power is, a noisy load (and microwaves are pretty bad in that department) will reflect back from the comparatively small generator when your pole transformer eats hundreds of times more harmonics for breakfast.