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how many watts does my rock tumbler use? Answered

i just bought a rock tumbler off ebay. the brand name is "chicago power tools".
its a basic 3lb capasity rock tumbler/ lapidary rotary tool.

now, because i live in australia, i have a problem, my power outlets produce 240v , and the rock tumbler can only take 120v, and so when i pluged it into a power adaptor (us-aus), the transformer gegan to work, then overheated and produced smoke, fortunately it still works .

now, i am going to go and buy a stepdown transformer and have learnt that if the device is using more than 90% of what the transformer supplies, the transformer will overheat or break or something.

now, on my tumbler, and everywhere a description for it is put, it mentions nothing on wattage consumption, and so i am asking , how many watts will it use so i may accordingly select a stepdown transformer for it.


When you say that you used a US to Aus power adapter, do you mean one that just adapts the pin configuration to fit a US plug into an Aus outlet?

You need a transformer (240V-120V), or power supply that you can control the voltage with and plug into that, or a 240V motor for the tumbler.You also say that when you plugged it in that the transformer began to work. Does the tumbler already have a transformer attached to supply the motor with a lower voltage? If so you just need to replace that transformer with one suitable for our 240V supply.

You can work out (roughly) the power consumption by multiplying the supply voltage by the current rating on the motor. The best way would be to measure the current the tumbler draws while operating under load and also measuring the voltage (once you get it right).

the brushless motors electromagnets are large pressed metal plates like a padlock, which are conected to the transformer.

like all transformers, it can take higher voltages than its rated for, it just overheats to fast for the fan to cool it down.

the adaptor i used was simply a pin adaptor, one that allows us appliences to plug into australian power points.\

also, what would hapen if say the tumbler needed 100 watss, but only 65 were being produced? would the transformer be destroyed, or would the mill?

when this happens with my small lego mill, it simply stops, what would the large mill do?

If the tumbler needed 100w and the power supply only produced 65w, the tumbler would most likely run very slowly until the power supply overheated, which would trip out it's safety devices or burn out the power supply if it has no thermal protection.

If the tumbler's transformer overheats because the fan can't keep it cool enough when you double the input voltage, then obviously it cannot handle voltages higher than it is rated for. If you increase the input voltage to the transformer, then the output to the motor is also higher. If you keep doing this you will destroy the machine.

Buy a transformer or power supply.

yes, it only changes pin assingment.

also, the rock tumblers motor is a brushless motor built into the transformer, which is inside the tumbler..

the motor has nothing written on it, as it is a brushless motor in a tranformer, which inturn has no writting on it either, as most transformers do.

its basically a brushless motor built into a transformer in the same way as old fashion electric shears and clippers were made.

the transformer is rated at 120v ac, and thats all the info i can get

Its an AC induction motor, by the sound of it. Running it on 240 has probably knackered it, you really needed to have used a transformer !


it aint knackerd, it is just really smells, and it works on 240v as well, it just overheats really fast

i am getting a transformer, thing is though, i need a transformer that produces more watts than the tumbler can use , because apparently, if it overdraws a current the stepdown transformer will destroy the tumbler.

hence i am searching for the wattage the tumbler uses so i may select a transformer that produces more.

Like I said earlier I'd suggest more than 100W, and measure the current, when you do.


I'm also in Australia, and a quick look on eBay revealed 240v to 110v 350W power supplies in the western Sydney area for under 50 dollars. Maybe even cheaper if you look around.

Does the motor it say how many amps it draws at 120V? If so, watts is volts times amps.

The instruction manual

says it should have the amperes marked on the name plate. This might be stamped on the motor itself under the unit's housing.

It's a 120v motor and has no transformer built into the unit. I recommend something along the lines of a clamp-on current meter which will tell you exactly how much power is going to the motor at a given load. (trouble is finding 110 volts to test it).

on the diagram, the transformer, is noted as the motor, but really, that is both.

I'd reckon on ~100W. I can't see it being more than that. What was the adapter you zapped rated at ?

what would happen if the rock tumbler were to exeed the wattage that the step down transformer could provide?

no, the plastic on the transformer powering the brushless motor, with the tumbler is what smoked, the plug i was using simply didnt cut down the voltage like i thought it would


i have just read that a size #3 tumbler will only use about 10-20 watts.
what exactly is a size #3 tumbler? does it mean by its weight capasity 3lb?