# Inverter problem



## rexos (Oct 16, 2006)

I have an inverter rated at 150w, which is fine for the TV, Freeview, DVD player etc, but will not power the`Mrs` hair straighteners which are rated at 35w!
Any ideas anyone please?
Thanks
Rex and Denise


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## DABurleigh (May 9, 2005)

Dunno offhand, but I remembered this one, so start there! 
http://www.motorhomefacts.com/ftopicp-179574.html#179574

Dave


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## Snelly (Aug 20, 2005)

What type is it??

Modified Sine Wave

Pure Sine Wave

Quasi Sine Wave

it can make a difference with some appliances...


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## rexos (Oct 16, 2006)

*Inverter prob*

Hello Shane,
Thanks for your reply, its a modified sine-wave type, the inverter doesnt growl or spit at me when Denises straighteners are connected, the led stays on, as opposed to when I apply a hair dryer, and it obviously `chatters` and shuts down.
Do you think the quality of the sine-wave is relevant to these expensive hair straighteners?
Rex


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## 101825 (Nov 18, 2006)

After messing about with modified sinewave inverters I finally bit the bullet and bought two pure sinewave inverters: 1.5Kw and 150w. Now my appliances work much better and the power pack of my computer doesn't heat up.

Roger


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## drcotts (Feb 23, 2006)

hair straighteners ...35w Are you sure of that figure seeing as a telly draws about 50w.. 

Phill


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## olley (May 1, 2005)

Hi just checked the wifes GHD's 35watts is right, but they do have a thermostatic control circuit in them, so maybe it doesn't like m/sinewave

Olley


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## spykal (May 9, 2005)

Hi

Maybe best to give up on the invertor and buy her a Braun gas powered one... :wink:

Here are a few more portable beauty tools ...<<<

and please don't ask what I was doing at a website called "Handbag.com" :lol: I googled it :wink:

Mike


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## Snelly (Aug 20, 2005)

After googling to confirm my suspicions, I can confirm that it is most probebly your inverter. You need a pure sine wave one. In which case you'd be looking at forking out a few quid. Maybe best to go with the "buy her some gas straighteners" suggestion!

http://www.itsnoteasybeinggreen.org...p=162638&sid=279954702088cfe103934ef2ce86dd00


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## Snelly (Aug 20, 2005)

Info from one of my suppliers Sterling Power Products:

Wave form! All inverters are attempting to mimic the mains 230 volt sine wave form. This ensures that all equipment to be run on an inverter receives the same input waveform for which it was designed. With some equipment such as heaters and lights the input waveform is not important. However with things like electric motors and especially microwaves, the waveform is absolutely critical to achieve correct running. There are three inverter waveform types, square wave, quasi sine and sine wave.

The first type, square wave, is not suitable for marine use because it has no voltage control. This means that the input voltage is proportional to the output, i.e. if the transformer is wound to produce 230 volts at 12 volts when the engine is running at 14.8 volts, the inverter would produce about 280 volts. This will cause catastrophic problems with onboard equipment. In order to overcome this regulation problem, the second waveform is used. This is called the step square wave or quasi sine. This waveform overcomes the regulation problem and maintains the output voltage over a large input voltage range. However it falls short of running a microwave 100%. A reasonable figure of 85 - 90% would be more realistic, with about 2% of timers not working. The big plus with this type of inverter is the cost, it is low cost and high performance, linked in with the fact that it will run 95% of general equipment such as microwaves, hair dryers, TVs, fridges, computers, drills, etc. This makes it the most popular inverter choice by far (about 100 quasi sine inverters are sold to 1 sine wave inverter). However, equipment that has thyristor control in it, such as washing machines, will not run on the quasi sine wave form. The best waveform by far is the Pure Sine wave, however this does not necessarily mean it is good for your purpose. The good side of a sine wave is it will run all equipment as well as the mains, however, the bad side is its cost and the fact that the quiescent current is about 2 - 7 times more than conventional quasi sine wave inverters (the Sterling units are about 2 times however other transformer models sold by our competitors are as much as 5 times more). Sine wave is a must when using washing machines and other thyristor controlled equipment. Some quasi sine wave inverters can cause a black line on the TV but not with sine wave inverters, most bread makers need sine wave and a small percentage of portable equipment battery chargers need sine wave.

**** where it refers to "square wave", that is modified sine wave ****


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## artona (Jan 19, 2006)

Hi

_and please don't ask what I was doing at a website called "Handbag.com" Laughing I googled it_

I am sure you did Mike, but did you order anything whilst you were there :lol: :lol: :lol: :lol:

stew


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## 101825 (Nov 18, 2006)

There is a chap in Bicester that sells 150w pure sinewave inverters for about £50. Send me a PM if you want his details. We bought a 1.5Kw pure sinewave with remote for £350 and very happy with it. It runs our hair straighteners, microwave, toaster, hair dryer etc without a problem.

Roger


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