240 vs 220

[Fairmountvewe]

Hello all.  Quick question.  My ST head is 220vAC.  I have an AVR and it holds pretty well under load, but.......

I live in Ontario-ari-ario, and our voltage standard is 240vAC.  I am running almost 10% under that standard.  My concern is running things like a refrigerator, stove or a washer/dryer that have some kind of computer board but maybe not an actual internal power supply.  I am not too concerned about running the 240v well pump, or the electric water heater (straight resistance load).  Am I putting my (quasi) electronic items at risk running this get head?  I am having a heck of a time finding anyone in this province that can supply an actual 240vAC 2 bearing head for anything resembling a decent price.  Thanks for your time, and have a great day.

Peter

[dieselgman]

Likely not a 100% answer... but, if your power output is steady on frequency 60Hz. then the actual voltage is somewhat flexible in most devices. Also, 220 ac vs 240 ac is sometimes used loosely as a descriptor or equipment rating. Any computer boards will convert this external ac supply via an internal switching power supply (often to 5volts) and regulation will be very close.

Generator head rating: This output value can be adjusted if you run an AVR on your generator head vs the harmonic Z winding (as used in some ST heads).  The brushless Stamford designs will be a much better power source for all things computerized and their output will be controlled with an internal AVR. Yes, they are much more expensive. They offer much less maintenance and longer life-spans.

I hope this helps, dieselgman

[32 coupe]

I see a lot of the equipment today stating it will run on 208 to 240.

I doubt you have anything to worry about.

[AdeV]

Chances are, it won't mind. Mains powered appliances, in this day and age, are pretty forgiving of the input voltage - and even frequency - given the massive worldwide differences in voltages. The real giveaway will be the specification plate, if it has one; this should give a voltage range: 208-240 is apparently "standard" in the US, given the differences in how you get to your 200+ volt outlets. Technology Connections made a good video on how the US mains system works, and why some outlets are 208v and not 240v (or 220v).

[38ac]

It seems to me that 220-240 is a range, not an exact voltage? Have you checked your grid voltage or just assumed it is 240? Our grid voltage varies a lot depending on usage. Runs 235 or so on nice days but have seen it as low as 219 when very hot in the summer, none of our appliances seem to care. My AVRs are adjustable via a pod on the board and I'd bet yours are. I have never installed them as my ST head both are very close without the added complexity.

[Fairmountvewe]

Thanks all for the help.  You have collectively eased my troubled mind.  To answer the question, I actually have measured my grid voltage (test before touch...) both at various 120vAC outlets and at the distribution panel itself and we were right at 120/240 each time.  As I said in my original post, I was more worried about things that have some small electronic board, but maybe no actual power supply (like the LED display on the washer) as I understand that a power supply will regulate the output to whatever is required, 5v, 12v, 120v etc.  I have tried adjusting the output voltage at the AVR via the pot, but mine simply won't go past 223vAC.  Again my thanks. 

[32 coupe]

I would be more concerned about the power from the "ST head" than voltage.

I have 3. Two of them are the earlier series with copper windings and are wound
close to "spec" in that they will produce a solid 120/240 output with no regulator.

The last one I purchased has copper windings but is so far out of spec that with no regulator
it will run about 370 volts output. It will not tolerate any imbalance between line loads.

One thing to also consider is that without some sort of voltage protection when and if you have
a drive failure (engine fail) something on the output side will fail. Could be as small as a diode or
regulator or an appliance being used.


I have pretty much given up on the ST heads. I still play with mine in that I regularly run the sets and
exercise the units with heat strips as loads but when I need to power the house I use sets I have built with
the Stamford "clone" heads because the power is better regulated (voltage, hz and sine wave) and if I do
have an engine failure the voltage will drop to a certain point and the regulator will "drop out" the head with
no damage to head or appliances.

With that said good luck and let us know how it works out.

Gary

[dieselgman]

I would be more concerned about the power from the "ST head" than voltage.

I have 3. Two of them are the earlier series with copper windings and are wound
close to "spec" in that they will produce a solid 120/240 output with no regulator.

The last one I purchased has copper windings but is so far out of spec that with no regulator
it will run about 370 volts output. It will not tolerate any imbalance between line loads.

One thing to also consider is that without some sort of voltage protection when and if you have
a drive failure (engine fail) something on the output side will fail. Could be as small as a diode or
regulator or an appliance being used.


I have pretty much given up on the ST heads. I still play with mine in that I regularly run the sets and
exercise the units with heat strips as loads but when I need to power the house I use sets I have built with
the Stamford "clone" heads because the power is better regulated (voltage, hz and sine wave) and if I do
have an engine failure the voltage will drop to a certain point and the regulator will "drop out" the head with
no damage to head or appliances.

With that said good luck and let us know how it works out.

Gary

Sound advice... The AVR controlled heads are a much better design and worth the extra cost for many of us using modern connected devices.
In addition, the Stamford copies (as well as originals) require no brush maintenance. typical 10,000 hour bearing service, and that is it.

dieselgman

[BruceM]

+1 on comments by dieselgman and 32coupe.   Check your voltage under full load, preferably with a true RMS voltage meter as the ST waveform is sometimes more triangle than sine.  Cheap meters are just scaling the peak voltage of a true sine.

If the stock harmonic regulator of your ST head, with no dropping resistor, can't get over 220VAC, you might eventually consider using an AVR, using the line voltage input instead of the harmonic input.  The AVR units can only limit what you are using for excitation; your harmonic output is marginal.  They do work find using the mains as the excitation source to the AVR; it will limit it.  You must pick the right AVR for your output voltage, 120 or 230/240.  You can find them for cheap on Ebay. 

Check for aluminum rotor windings next time you check your brushes/commutator.