3.3Kva Voltage Transformer/Converter
Dear All,
As far as electrical & electronic terms and what not is concerned, I’m illiterate. I had placed an order for a step-down voltage transformer/converter. Since I have yet to receive the shipment, I cannot tell more than what appears in the catalogue.
The spec says it is to be used in 220/240V country for 110/120V machines/appliances. I do not know what is the wattage capacity of the transformer, but written as 3.3Kva in the product description.
My question 1. What is Kva anyway ?
2. My machine is pre-wired 115V and fused at 14A. If I am not wrong the in-put wattage is about 1,600W (115V X 14A=1,610W). Can I operate the machine using this so called 3.3Kva transformer ?
3. Looking at the pic of the transformer, I supposed the round socket can only accept round plug. If my machine is supplied with standard US 3 pin plug, do I have to use another socket adaptor ? Correct me if I’m wrong.
Please find the pic of the transformer.
Thanks
Edited 8/10/2006 12:02 am by Masrol
Replies
KVA is an abbreviation for kilo volts amps. For transformers of this type, where you can get many different voltages depending on how you hook up the various windings, it is easiest to rate the transformer with volts-amps. That's the product of the output voltage and the maximum current at that voltage. For instance, you might find a transformer which can be hooked up to provide 10 volts and 10 amps. When you fiddle around with the windings so that it produces 5 volts, you can expect to get 20 amps from it, because it is a 100 volt-amp device.
Yes, you can use a transformer at less than maximum load. You can pull 1600 volt-amps from a unit rated for 3300 volt-amps.
Hi Jamie
With your explanation I feel more confident now.
Thank you very much.
Masrol
In this particular situation you can say that 3.3kva is 3.3kw or 3300 watts. I can't tell from the picture what outlets it has on it but you should be able to change the plug on your equipment to match with no problem.
Jack
Thank you Jack.
Masrol
Do check again with the supplier. The illustration shows a UK 240 volt input plug fitted and I do not know if the cycles difference between the US and the UK have any relevence in this instance.
The transformer you show is a typical UK site transformer with 13A input and the UK 110 output recepts. It is possible to mount a north american duplex recept in place of the uk ones .However I have adapted a North American powerbar by adding a UK plug to the cord,then one can leave things plugged in .This can be an issue if several people are working at once and no one keeps an eye on the total load.
You haven't mentioned what you intend to run with the step down transformer, but be aware that in addition to voltage and amperage there is a question of frequency.
Some motor designs, such as the universal type motors that use brushes and are typically used on hand held power tools aren't bothered by frequency. Induction motors, which are typically used on stationary tools with a belt drive, can not be used on the wrong frequency because they will be damaged, especially if the frequency is lower than the motor's design frequency. Almost any tool that must be run on a specific frequency will list the required frequency on the tool's spec plate, though I am not sure that lack of a frequency listing guarantees that any frequency is allowed.
If you have tools made for the American market they will be designed for 60 cycle power, Canadian tools are 50 cycle. Much of the rest of the world is also 50 cycle I believe, so you will have to do some additional research as to the type of motors your tools have and the new frequency before you plug anything in. The transformer you have ordered will only change voltage, it does not change frequency, that is a technically more difficult and expensive proposition.
John White, Shop Manager, Fine Woodworking Magazine
Dear John White
Thank you for your reply.
I am in a 220/240V 50hz country. I intended to run any US market machine with input capacity within the range of 1,500 watt to 2,000 watt or maybe higher. I know that most US market machines are designed for 60hz cycle/frequency.
I did make a check on how a voltage converter works. It just converts the voltage and not the cycle. From the info I gathered, a voltage converter may work well with most power machines that are not cycle sensitive. And I do not think a circular saw or router machine is cycle/frequency sensitive.
Until I can find a voltage converter that converts both the voltage & cycle, I hope my machines will be fine. And most importantly, I am safe.
Thank you
Routers and circular saws are always universal motors so you shouldn't have a problem using them on 50 cycle current.
John W.
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