Hi all,
I'm wondering if anyone can tell me about how mains voltage varies within North America.
I recently shipped a few electronic gizmos, and one user on the west coast reported problems with the unit. After inspecting it, I found the cause to be excessive ripple in the power supply when being powered by insufficient voltages.
Here, I measure 122.5VAC out of the wall. As I've read, the nominal voltage is 120VAC with a variance of +/- 5%, which would be 114v - 126v. My circuit would definitely have problems with 114VAC. What do people do in this situation, design for 114V or even lower?
Hi all,
I'm wondering if anyone can tell me about how mains voltage varies within North America.
I recently shipped a few electronic gizmos, and one user on the west coast reported problems with the unit. After inspecting it, I found the cause to be excessive ripple in the power supply when being powered by insufficient voltages.
Here, I measure 122.5VAC out of the wall. As I've read, the nominal voltage is 120VAC with a variance of +/- 5%, which would be 114v - 126v. My circuit would definitely have problems with 114VAC. What do people do in this situation, design for 114V or even lower?
Mike
MrAl, are there really any electrical standards for that? Most of my experiences come from the general 10% number for motor/light industrial devices. I'd take 15% to heart though because you can never design with too much wiggle room if you can afford it =)
I don't ask for standards Willy Nilly MyAl, I want to see the black and white letters of the standard, so where's the white paper? What is used in Industry is often rule of thumb with varied terminology from region to region with differing electrical codes.MrAl said:Yes that's the standard
These voltage ranges apply to steady-state voltages, and do not apply to momentary voltage fluctuations, caused by switching operations, motor starting, fluctuating loads, and other normally occurring electrical operations
... but I doubt that'd be sufficient if the voltage drops as low as 110VAC. I'm currently looking for a variac to add to the workbench to be able to test these things better.
...
I'm generating +/-15V using a 12VAC 1000mA wallwart with one side going to ground and the other going to a pair of diodes, splitting off to 2200uF filter caps and standard LM317 and LM337 regulator setups.
I don't ask for standards Willy Nilly MyAl, I want to see the black and white letters of the standard, so where's the white paper? What is used in Industry is often rule of thumb with varied terminology from region to region with differing electrical codes.
If you say 15% I say it's a good idea, but if you say it's a standard I'm going to need a technical document specification that is universally accepted, or it's no standard; just someone else's opinion. Regardless of how long you've been in electrical industry if you've been in electronics for any length of time you should understand the important of documentation in standards, for without documentation there is no standard.
That's a really poor design choice - you don't want a 12V transformer feeding 15V regulators, particularly with crude half wave rectifiers, even with the mains at the noiminal 120V. Use at least a 15V transformer, and preferably 15-0-15 with full wave rectification.
I don't trust working standards, too many different versions of them, and I find it especially criminal that the entire US power grid relies on a working standard. I've always found the divergence between groups such as electricians and commercial/industrial electrical engineers and electronics to be night and day, totally different mindsets.There is more than one type of standard, one being a written standard and another being a working standard.
That's self evident, transients and externally injected noise are possible in many situations, this however can be designed into the written standard with broad guidelines and caveats where appropriate. But I think things like expected line voltage at the junction box to a home should have a set standard that is clearly defined.Another question you can ask yourself is, after reading the standard then why does anyone need a line conditioner
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