Generators, voltage quality, and "sensitive electronics"

[rbstern]

We've had more power outages this year than in years past, and I have been remiss in not being better prepped. We have two homes on the property, each with their own breaker panel. But the homes share a well system with pump and pressure tank. If we lose power, we only have the water in the tank. Want to be able to power the well pump from backup generator.

Have a couple of 5500/4800 watt, dual fuel Duromax generators. I have used them for small projects. They are electric start, and reliably start on propane. Have avoided ever putting gasoline in them, to improve their reliability.

I have most of the wiring done to hook one to the house with the well power, via a genny plug and 240v/30A circuit. Just need to install the manual lockout disconnector and breaker in the panel.

I've read many times about the potential to damage electronics with generator power. Have never heard of a real world example.

Anyone have experience with this happening?

 

[skipmarcy]

My experience with running the 1 hp well pump I have is that I'm not sure your size generator will handle it. I've run mine on a 7500/9000 watt and it really works it to start the pump. I only use it to refill all of our water containers every several days during an extended outage - not run the house water system as normal. I think it would cause pump motor damage in the long run just from my experience trying it.

As far as the electronics damage, I've never experienced any problems with our appliances or electronics over the many years using conventional generators.

 

[Diggin It]

Before I went to generators, I relied on a variety of UPS units. I had several around the house and had a number of electronics plugged in .... TV, audio, computers, etc. Of course, that only gave me enough time to shut stuff down normally instead of a sudden outage. One of their main purposes was to filter power and bridge those short, momentary outages.

Eventually I picked up an off-brand portable generator and several cords. That worked for a while, but eventually the UPSs started freaking out when on generator, beeping, buzzing, flickering and so on. Conclusion of people I talked to is that the generator was putting out less than prime power and the UPSs could no longer handle it. No one could confirm if the generator was going bad or if it had degraded the UPS internal electronics.

I now have a whole house unit, but have not had an extended outage to see how it works. I have manually killed power and run on generator for 3-4 hours with no problem from any of then devices.

I would not trust valuable or sensitive electronics on a portable generator without some sort of extra filtering.

And no, I don't think a 5500/4800 is going to run a well pump. I'd say 10K at a minimum.

 

[Eagle1]

My well pump draws 12-15 amps running but ~30-50 amps on startup. Most consumer grade generators do not output a pure AC sine wave, more like a pulsating DC. DC electronics have a power supply and should handle that no problem. Older stuff was way more sensitive but now stuff has to deal with crappier power and grounds anyway.

 

[cqaigy2]

I use UPS's too, on the entertainment system and computer/network stuff.

I'm trying to remember the last time i fired up the well, was a 1hp 3 wire submersible, approx. 390' deep. 5KVA generator, maybe peek was 6. It was able to start and run the pump motor and pump into the cistern. We have a pressure pump too, didn't run both at the same time. Using an inexpensive multimeter, the initial current draw was around ~20 amps and would drop to around 12ish. I pumped probably a few hundred gallons into the cistern, before shutting it off. Didn't need the pressure pump because well and cistern sit uphill and provides enough drop for usable pressure at the house.

 

[blee03]

Good info here:

"In a traditional generator, the power produced by the alternator is fed (more or less) straight to the control panel. It may go through a voltage regulator or other protective devices, but the power is not necessarily “cleaned up”. Therefore, the power produced by a traditional generator has a higher total harmonic distortion (THD) than the power produced by an inverter generator. THD is a measure of how clean the power is – more on that in a moment.

An inverter generator works differently. The alternating current (AC) power produced by the alternator is sent to a rectifier, which is a device that converts the AC power to direct current (DC). This DC power is then inverted back to AC power by the computer inside the generator before it is sent to the control panel. This is where the name “inverter” comes from. Because the power to the control panel is controlled by the computer, inverter generators offer much lower THD than standard generators. THD is an important consideration when powering sensitive devices, like smartphones, tablets, computers, and televisions. These devices expect “clean” power (power that has low THD, like the wall power in your home), and can be damaged if they receive high-THD power. All WEN inverter generators use pure-sine-wave inverters, and as such, limit THD to under 1% in most cases. Traditional generators can produce THD as high as 25% in some cases."

How Do Inverter Generators Work?

NOTE: If you're looking for a more basic explanation about the benefits of inverter generators, check out our post explaining their advantages here. If you’re in the market for a new generator, you’ve probably noticed by now that there are many different types of generator – standby, portable...

wenproducts.com

 

[seville009]

I blew out the control panel to my relatively new furnace one time because the whole house generator was running too high (above 60 mhz or whatever it is supposed to be).

Could see that the lights were a little brighter when the generator was running, but I’m no electrician…..

Have the generator serviced each year now.

Also have a whole house surge protector - never had any surge issues, so I can’t really say if it works or not.

 

[Oaktree]

Most consumer grade generators do not output a pure AC sine wave, more like a pulsating DC. DC electronics have a power supply and should handle that no problem. Older stuff was way more sensitive but now stuff has to deal with crappier power and grounds anyway.

I use UPS's too, on the entertainment system and computer/network stuff.

I've found that many UPSs, especially the smaller <1000VA units (the ones you get at Staples for computers, etc.) don't like the ratty power the lower price generators put out very much. They'll keep switching back and forth between line and battery power, causing fluctuating load on the generator. Went round and round on this at a worksite where they'd put in a Home Depot Generac before we figured out what was causing this.
Some of the more enterprise-level UPSs (APC at least) have a sensitivity adjustment that allows them to accept less than ideal power quality.

 

[DieselnHooters]

Our suitcase type Honda 2000 watts inverter gen runs the 1HP pump fine, it peaks in the 12-15 amps area and the well is 50 feet deep.

 

[mrmikey]

Me personally, I wouldn't run any electronics off a non-inverter type generator. I will continue to run my well pump, water heater, lights and fridge off a conventional style and have been doing so when required for the past 10 years. At least once a winter we lose power for any where's from 1 hr to 12.
I was going to buy a new inverter style to run my heat pump but I figured in the summer it's not necessary or life altering not having AC, in the winter I have a wood stove. Besides, the price of an inverter type big enough to run what I want is way out of my price range.....Mike

 

[Oaktree]

Me personally, I wouldn't run any electronics off a non-inverter type generator. I will continue to run my well pump, water heater, lights and fridge off a conventional style and have been doing so when required for the past 10 years.

Don't modern refrigerators have a lot of electronics in them now too?
That having been said, I haven't had any issues running one off a generator. I know people who'll run tvs off (non inverter) generators with no problems, maybe the somewhat ratty power isn't as big a deal as it's made out to be?

Curiously, why do these generators put out noisy power to begin with? Isn't it just a coil with spinning magnet (or something similar)? Given how noisy the power is from 12V inverters (like you'd use in a vehicle) you'd think inverter generators would be worse than regular ones.

 

[orezok]

While I have a Generac standby to power the critical items in my house, it doesn’t have sufficient overhead to handle the new quad mini split (48000) I installed earlier this year.

When I installed the mini splits I used the circuit which used to feed the 17 year old AC.

Living in the desert AC is mandatory especially during the monsoons. I bought a Wen 8750 inverter to dedicate to the mini split. Less than 1% THD. I installed a 14-50 outlet downstream of the disconnect which allows me 120/240 power available at that location, but becomes a feed input from the generator by pulling the disconnect before energizing. Yes, I know a suicide cord is required, but I know how to handle it properly by plugging it in to the “outlet” before plugging into the generator. Only me and my wife live here and she would not be able to move the gen from storage and hook up so no safety problem.

After I installed it I tested the system. First off, the ramp up amps during start of the compressor is virtually non existent. In fact the data label on the split lists LRA as 0!

I put all 4 air handlers on max temperature and the total electrical draw per Fluke was less than 14 amps, well within the generators output.

I have had to use the gen one time this season and all worked well.

 

[i7win7]

Have an APC 1500VA UPS on a pellet stove. When the power fails it starts beeping, have 10-15 minutes to get a Honda 1000w inverter generator out, running and plugged into stove. The APC UPS produces a modified sine wave (stair stepped) and the AC motors growl as they try to speed up and slow down on a stepped sine wave. Everything OK after switching to Honda.

Working on upgrading the stove to an Ecoflow pro max solar generator with thier smart gas gen. for backup. Shouldn't have to get up in the middle of the night to have heat in the morning. May have slightly lower AC bills

Non inverter gens have a pure sine wave. The voltage or Hz (cycles per second) could be off. The electronics to control these generators are simpler, sometimes non existent (PTO gen).

Inverter gens add more electronics to control the sine wave. Buy a quality gen to hopefully get quality electronics. Personally I would avoid H.F. and cheep Chinese gens for this reason.

 

[mrmikey]

Don't modern refrigerators have a lot of electronics in them now too?

Probably, mine is just a fridge tho, nuthin' but thermostat and compressor cooling an insulated box. No water maker, internet, zone control, foot massage, tv, laptop, nutting but cold . Same as my stove, washer and dryer...least ways until they die and I have to get new crap......

 

[Agvg]

I do believe modern switching power supply are quite tolerant and can handle a lot of not so perfekt input, cheap square wave inverters should be much worse than a generator any way you look at it.

 

[ponytug]

We've had more power outages this year than in years past, and I have been remiss in not being better prepped. We have two homes on the property, each with their own breaker panel. But the homes share a well system with pump and pressure tank. If we lose power, we only have the water in the tank. Want to be able to power the well pump from backup generator.

Have a couple of 5500/4800 watt, dual fuel Duromax generators. I have used them for small projects. They are electric start, and reliably start on propane. Have avoided ever putting gasoline in them, to improve their reliability.

I have most of the wiring done to hook one to the house with the well power, via a genny plug and 240v/30A circuit. Just need to install the manual lockout disconnector and breaker in the panel.

I've read many times about the potential to damage electronics with generator power. Have never heard of a real world example.

Anyone have experience with this happening?

Generally, well pumps will draw 3-7times their running current at start up. Unlike most other loads, they start at zero rpm against a full load. So, unless the well is shallow, and low flow, I wouldn't bet on a 6kW generator starting the well more than a few times. I.e. there is a real risk that you will burn out the generator. I also wouldn't want anything else hooked up when the generator was trying to start and run the well, as the voltage drop on start is likely to be large (aka brownout), and the voltage overshoot when it stops may also be large, depending on the type of generator that you have.

There are three main types of generators;

• Old time brush generators that put out sine wave AC (no regulation beyond engine throttle for frequency, and may have very limited voltage regulation, as in only a capacitor or diode)
• Newer brushless generators that mostly have some form of voltage and frequency regulation (some much better than others)
• Inverter generators that make high frequency AC, rectify it to DC, and then transform the DC to tightly regulated AC (in terms of voltage, frequency, and distortion)

I have one of the first type, 4kW, and it is actually pretty good, and I use it around the property for running portable tools, I.e. one skill saw, or one electric chainsaw. Voltage is within 2% of specification no load to full load, except when a motor starts, and then the voltage drops 10% and 5Hz or so. Ok for motors.

I have two of the second type, and they both typically hold both voltage and frequency within 2% no load to full load. (Suddenly dropping an extra 2kW, on an existing 2kW load for a total of 4kW transiently drops 2Hz, and 3-4% in voltage.) The 5kW diesel happily runs the whole house, except for the electric dryer and AC. Both have solid automatic voltage regulator circuits built in, and it shows.

Inverter generators have very clean power, but, and it is a big but, they don't usually have the surge ratings of the other two generators, making them less ideal for starting wells. The largest that I have seen are around 8kW, so they may be able to start a 1.5-3HP well motor.

"Electronics" covers a host of products, some quite sensitive to power specifications and some not very. Read the label; if it says something like "AC 100-270V, 50-65Hz", it will probably be just fine on a generator. If it says "120V, 60Hz", you can't bet on it being happy, and if it is pricey, I would not put it on a random generator without testing the generator to see how well it puts out 120V/60Hz, both loaded and unloaded, and ideally testing to see what the harmonics look like.

So, @rbstern I kind of doubt that you would be happy starting your well pump with the 5kW generators. I suspect that they won't last long, but you might get lucky.

All the best,

Peter

 

[TheMan419]

We run our well pump off our generator. Have had zero problems with it. It is not a name brand but the engine is a honda. I would not run electronics off of it. I'd love to get a big Champion inverter style generator so I can just run whatever I want.

Need to check the starting draw of your pump to make sure you have enough power. Mine generator is 6900/8500. It can start the pump no problem. As long as I am not running a bunch of other stuff at the same time.

 

[RalphVa]

We used to run our well pump and frig/freezers/lights/etc. on a little 4,400 watt generator. Had to take everything off to start the well pump.

Now have an Isuzu diesel drive generator that runs the whole house but for the big heat pump and swimming pool pump and some other big stuff like the stove top and oven.

The electrician carefully adjusted the run speed on the Isuzu to get the right voltage. Never did anything to the little generator. Never had any electronics problems.

 

[newbury]

Can you install a soft starter on a well pump?

 

[orezok]

Can you install a soft starter on a well pump?

This MIGHT work for a pump motor. It’s designed for AC or compressors, but the motors aren’t a lot different. Give Ziller a call.

SmoothStarter SS230V1P16-32 Scroll (16-32 RLA) Single Phase – Ziller Electric

NO MORE DIMMING LIGHTS WHEN YOUR AC TURNS ON This model ONLY works on compressors with RLA (Rated Load Amps) between 16 Amps and 32 Amps. CLICK HERE TO SEE SS230V1P08-16 Scroll (8-15.9 RLA) Single Phase This product has been developed specifically to soft start large single phase compressors and...

www.zillerelectric.com