FAO Electronically Minded People

[Tom 14021]

I got an amp through the post today and Fender have included the wrong power lead.

 

So they gave me a European two pin.

 

However the amp operates with a Kettle lead (230v/50hz), which at the moment I don't have.

 

However I do have a kettle lead that operates at (250v/50hz), so it's more powerful but the frequency is the same.

 

Is that usable?

[Jimbo 175]

Totally usable, UK mains voltage is often quoted as 230v, although its strictly speaking 240v.

[Tom 14021]

Nice one!

 

The very though of getting a brand new amp I can't even use till I get another cable is fucking horrible!

 

I'm getting one sent out tomorrow but the one I have in my possession will do i guess

 

Cheers Jimbo

[Park Life 71]

A few mins later: KABAAAAAAAMMM!!!

[Rob W 0]

Voltage figures are "nominal" anywhere - they vary quite a bit through the day - I think +/- 5% is quite normal and it can be +/- 10% dependent on wher eyou live

 

It only gets serious if you swop an American system for a Yuropean one TBH

 

Power supply variations - standards & tests

 

If you are a manufacturer or user of electrical equipment, power supply variations could be the cause of a number of operational headaches. To help overcome such problems, there are a number of standards relating to power quality together with complementary tests to verify equipment's ability to operate properly during accepted power variations. Below is a brief in-sight into just some of the potential problems relating to supply irregularities, relevant standards and tests:

 

Around 10 years ago the European public low-voltage power supply network was harmonised to 230V between phase and neutral conductors and the UK supply regulations (HD472) were amended to reflect this change. However, it was decided to widen the low-voltage tolerances to 230V +10% -6% for 10 years and then extended a further five years taking the transition period up until 1 January 2008. As a result, in parts of the UK nominal voltage is still 240V, which contributes to inaccuracies in power consumption and ratings calculations. Consequently, some imported equipment that runs happily on its home supply might not function correctly in the UK (e.g. its output rate might be too low or too high), or it might be unable to operate at all.

 

Although such situations are unusual in the UK, this issue could be a more important consideration for equipment that is to be exported to a country with a less well-controlled power supply. Exporters should therefore verify local supply and fit a UPS or voltage stabiliser for locations where supply is erratic.

 

Voltage sags, dips and interruptions:

 

Voltage sags, dips and short interruptions are commonplace, although there is a European power quality standard, EN50160:2000 (voltage characteristics of electricity supplied by public distribution systems, that provides the limits and tolerances of these and other phenomena that can be expected). Voltage sags or dips, defined as having duration of less than 1 minute, at a level of less than 85% of the nominal voltage can occur up to 1000 times per year, whereas short interruptions (less than 1% of nominal voltage) are permitted up to 50 times per year with durations of up to three minutes. Therefore, it is most important to test electrical equipment to ensure that software, safety-interlocks and self-resetting equipment can operate correctly under these conditions.

 

Also, because the power quality standard allows for accidental, long interruptions (duration > 3mins) to occur up to 50 times per year, systems that incorporate PLCs or other programmable devices should be tested to ensure correct start up is achieved after an unplanned shutdown caused by power loss. The appropriate test method for this is EN/IEC 61000-4-11.

 

It is equally important to ensure that heavy loads do not cause unacceptable dips in the supply when they are started. One way of avoiding this is to fit a soft-start. Most variable-frequency motor drives include this as a standard feature but in instances where variable speed is not so important (such as in the case of compressors or air-conditioning fans) then a more cost-effective solution is to fit simple electronic soft-start to achieve a progressive increase in the start-up voltage over the first few mains cycles after switching on.

 

Generally, one would not expect power frequency variation to be a problem but, if the power source is a stand-by generator, such as in the case of hospitals (which have to test their generators for half a day every few months), the situation could arise. Also phase-unbalance is something that most installers of electrical systems are aware of but problems of this nature are not uncommon. Therefore, these are two phenomena which have to be considered and appropriate immunity tests are recommended.

[Matt 0]

In non-tech terms, the cable will probably be the same standard anyway, so it's all about the supply and the equipment in question. Cable standards are more about current (amps) rather than voltage.

 

Or what Rob said.