Is it possible to "clean up" my older generator's power for sensitive electronics?

[Larry Caldwell]

I've several older, but well running generators in the 7K to 15K range. But with the increasing addition of sensitive electronics to almost EVERYTHING I'm apprehensive about using them to run my devices.
I had initially thought just slap a UPS in the loop, but now they can be fried by dirty power (or so I've read).
Is there any inexpensive solution short of buying all new generators?

I have an old darkroom line stabilizer that I use when running electronics off of a generator. It's a big auto-transformer and capacitor that automatically holds voltage stable. Thanks to about 20 lbs. of iron and copper, plus a huge capacitor, it also filters spikes and RF noise, though that was not a design consideration when it was built. You can pick up a decent power conditioner pretty cheap, because they have little or no active electronic components. They are designed to take a ratty power input, filter and stabilize it. There is no battery backup.

 

[MTGreen]

Please educate me here:

Is the perceived issue with generators potentially having too variable voltage output or too variable frequency output or both? Or is it with AC RF noise?

Nearly all modern consumer grade electronics run on DC with an AC/DC converter. My understanding is there are one or more capacitors after the rectifier in the wallwart or power supply that perform a smoothing/regulating function for both. The rectifier also negates frequency fluctuations. In addition, the stepdown transformer in the same unit by it's nature reduces voltage output variability by a factor equal to the voltage stepdown. For example if you have a 10:1 stepdown transformer reducing 120v to 12v it always reduces by a factor of 10 -so 125v input yields 12.5v output, 115v input gives 11.5v output, etc. Typically electronics are designed to run at a fairly large range of input voltages -a 12v unit may work at 8-15v for example

So I'm trying to understand if this is a legitimate current issue given modern DC electronics and power supplies or a carry-over from older lower technology times, especially with hearing from many here that it's been working fine for them?

 

[Larry Caldwell]

Step-down transformers are obsolete. Nowadays they just rectify the juice into a cap and use an IC to extract the power. On the up side, the electronics are indifferent to input voltage, and will work anywhere in the world where line voltage is between 50v and 240v. However, they are vulnerable to spikes and RF interference.

 

[MTGreen]

Step-down transformers are obsolete. Nowadays they just rectify the juice into a cap and use an IC to extract the power. On the up side, the electronics are indifferent to input voltage, and will work anywhere in the world where line voltage is between 50v and 240v. However, they are vulnerable to spikes and RF interference.

So is there anything wrong with just using a surge protector and a ferrite ring and calling it a day?

 

[Larry Caldwell]

So is there anything wrong with just using a surge protector and a ferrite ring and calling it a day?

I have no idea what a ferrite ring is.

 

[MTGreen]

I have no idea what a ferrite ring is.

For RF interference reduction around cords aka ferrite bead:

Ferrite bead - Wikipedia

en.m.wikipedia.org

 

[ponytug]

Please educate me here:

Is the perceived issue with generators potentially having too variable voltage output or too variable frequency output or both? Or is it with AC RF noise?

Nearly all modern consumer grade electronics run on DC with an AC/DC converter. My understanding is there are one or more capacitors after the rectifier in the wallwart or power supply that perform a smoothing/regulating function for both. The rectifier also negates frequency fluctuations. In addition, the stepdown transformer in the same unit by it's nature reduces voltage output variability by a factor equal to the voltage stepdown. For example if you have a 10:1 stepdown transformer reducing 120v to 12v it always reduces by a factor of 10 -so 125v input yields 12.5v output, 115v input gives 11.5v output, etc. Typically electronics are designed to run at a fairly large range of input voltages -a 12v unit may work at 8-15v for example

So I'm trying to understand if this is a legitimate current issue given modern DC electronics and power supplies or a carry-over from older lower technology times, especially with hearing from many here that it's been working fine for them?

The problem with "dirty power" is that it comes in all sorts of flavors, and whether it is a problem depends on what is being powered. So, yes, you can fry lots of modern electronics and motors with "dirty power", but the "who, what, when, where" will differ. In general, motors care a lot about voltage and harmonics, semiconductors (digital) care about RF/EMI "noise", voltage, voltage spikes, and harmonics.

Most power supplies have some amount of filtering on the AC line to keep the power supply noise from leaking back out, but that is mostly focused on leaking out, not coming in. The internal design of modern power supplies is a lot more complicated than what you describe. Pretty much since the 80s, there have been microcontrollers to regulate the power by switching large transistors (MOSFETS/IGBTs) at high frequency to make DC (or AC for pure sine wave). Lots of fine tuning to make the voltage very stable.

Generator power controls, other than inverter types, are much, much simpler, but even so, most modern ones have pretty sophisticated voltage regulators, and it can be very productive to upgrade an older generator with a higher quality regulator.

Does that help?

All the best,

Peter

 

[MTGreen]

Thanks Peter that was very informative.
So upgrading to a modern quality regulator sounds like a good solution at least for my needs. Is there a good user friendly source for these as packaged units or does one need to order by specs from Mouser or the like?

 

[ponytug]

Thanks Peter that was very informative.
So upgrading to a modern quality regulator sounds like a good solution at least for my needs. Is there a good user friendly source for these as packaged units or does one need to order by specs from Mouser or the like?

I think that there are a number of folks who make good modern automatic voltage regulators. Stamford makes a variety of quality regulators, and there are many clones. If it were me, I would do some Google searches for your generator models and see whether there are drop in replacements, and what other owners may have done. The basic principle in any voltage regulator is the same, but tuning the voltage/current to the excitation/field coils takes some careful calibration so as not to fry anything. The good news is that you would be starting from a working voltage regulator, from which you could get some numbers to get a new voltage regulator in the ball park, before tuning it on your machine.

I'm of the view that if you depend on a generator to cover you when the chips are down, it is worthwhile stocking spare parts like carburetors, injectors, filters, relays, and, since we do depend on them, yes a backup regulator. I think the regulator for one 6kW cost $20, and perhaps $60 for a 10kW.

All the best,

Peter

 

[goeduck]

I have a Gillette generator that has a Honda GX engine and "Kleen Power" Technolgy on the generator. Rated at 7% THD where commercial power and Honda Invertors are around 3%. No problems other than possibly 1 garage door opener that died of unknown causes a month or so after the house was on the generator. I guess it all depends on your generator.