Inverters transformers and frequency

[Gordon]

Now here is something for you technical guys to think about.

I have a small 300 Watt inverter on the boat, I use it to charge a camcorder/digital camera/lapdog mainly, all switch mode power supplies.

I do however possess a rechargeable electric razor, although shaving and boating are not things that go together in my mind.

Now this rechargeable razor is a very expensive high quality bit of kit, it cost £3.95 in the garage at Wroxham!!

Having plugged it into the inverter it did not charge for long, investigation revealed the primary of the transformer had gone open circuit, maybe cos it was cheap and nasty or maybe........ What is the output frequency of an inverter, clearly mains transformers are designed for 50Hz. So the question is is my theory right and can you use equipment that incorporates a transformer with an inverter

Oh and the razor I replaced the XFMR with a weed lighter plug and a 120 ohm resistor, wonderful 12v charging now

[mbird]

Gordon

I'll stand to be corrected, but I think this is one of those quasi-sine versus pure-sine output problems I was on about in another thread. The output frequency of both is 50Hz irrespective of the type of sine output. I would have thought the constant on-off-on-off of the quasi-sine output from cheaper inverters could interfere with the transformer operation.

As I say though, I stand to be corrected. Our pure sine inverter charges my sons PSP via the mains transformer with no problems.

[Gordon]

Mark, I think you are right, I have now got myself all intriguied about this I have confirmed that these things do give a 50hz quasi sine wave, so the frequency issue is laid to rest in my mind. I was mixing it up with inverters with specifically designed transformers designed to work at higher frequencies, eg in aircraft or old mobile radio equipment. My mind has now turned to the waveform , I am going to have to bring the damn thing home and look at it on a scope to satisfy my own curiosity, if it is nearer square than sinusoid i would expect the peak to be much lower than if it was a sine wave to give the correct average voltage. I hesitate to suggest RMS as that surely can only be applicable to a oure sine wave. So its gotta come home to satify my stupid curiosity. The demise of the transformer is surely down to its cheapness