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Old 06-02-2008, 01:06 PM   #1
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110V-230V compatible electrical motors ??h?


What's the difference of a 110V 60Hz and a 240V 50Hz electric motor, found in electric handtools for instance ?? Does the manufactors really develope seperate motors for the different markets or is it a simple way to make them work on ether voltage?? Asking because same brand tools cost under half in US, compared to home (Norway).

Bought a Bosch batterydrill from US (because I have a compatible batterycharger (220V) for my Bosch impact driver) So I tried experimenting on the 120V charger. connected it to "earth-voltage" (190V on the meter) and it seemed to work fine (of course earth fault switch broke the circuit were mounted). Tried to connect it to 240V and it worked fine for about ten seconds (same output voltage), then the fuse inside the charger blew. Can I just get a "bigger" fuse for the printed circuit board?? The fuse that blew read 5A 250V....

hope anyone can help me understand a little more

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Old 06-02-2008, 02:07 PM   #2
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110V-230V compatible electrical motors ??h?


My understanding is that nothing with a motor or with any electronic components can be operated on an electrical frequency it was not designed for. So a 60hz drill, even put through a 110-230 voltage transformer would be damaged by the 50 hz electricity you guys have over there.

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Old 06-02-2008, 10:14 PM   #3
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110V-230V compatible electrical motors ??h?


This might get somewhat complicated here, if so, I (or one of the other electricians around here) will try to explain it better.

As for voltage; imagine voltage as pressure in a pipe. Higher voltage=higher pressure. Suppose that a pipe is rated for 150 pounds of pressure. If you have 120 pounds of pressure in it, it'll hold just fine. Suppose you put 220 pounds of pressure to it. BLAM!! The same is true with operating an electrical device on too high of voltage. That's why the fuse blew. A 120 volt charger cannot be operated directly on a 220 volt line. It needs a transformer to reduce the voltage to something it can handle.

As for frequency (60HZ vs. 50HZ); this will have no effect on anything that's a resistive load. An incandescent light bulb or a heater are resistive loads. It will have an effect on an inductive load. A transformer or a motor are inductive loads. With most transformers, 60 or 50HZ isn't much of an issue. Motors come in 2 basic types, universal and induction.

The universal type is easily identified by the existence of brushes. (The things inside that spark whenever it's running). Usually this type is small and portable. Kitchen appliances and hand-held power tools have usually have them. 60 vs.50HZ has very little, if any, effect on this type of motor.

Induction motors, on the other hand, are greatly effected by frequency. The speed of the shaft is directly related to the frequency of the input power. Generally speaking, a 60HZ induction motor operated on 50HZ will have an output speed of 5/6 of the 60HZ rating. For example, a motor rated at 1725 RPM at 60HZ will operate at around 1435 RPM at 50HZ. There are other factors like voltage vs. frequency that can complicate things a bit here, but generally small motors will work OK on either frequency.

Rob
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Old 06-03-2008, 11:32 AM   #4
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110V-230V compatible electrical motors ??h?


Good job Rob. It should be noted that 60Hz induction motors in particular are subject to damage if installed in a 50 Hz system. However, I have witnessed several running in this exact situation and they are holding up to a degree. These motors came from overseas and the company did not realize the issue. I told them to run these motors until they quit, rewind them for 60Hz, or install a VFD. They opted to run them. It has been a couple years and word has it they are still running. Fortunately they are driving high reduction gear boxes, thus reducing current and running at the high end of the nameplate RPM.
The VFD suggestion was my choice as they could run the motors at 50 Hz (simple program entry) and have the added benefit of the VFD.

Note: VFD Principle
480 Volt system. 1800 rpm motor.
480 @ 60Hz = 1800 RPM (plus or minus slip %)
240 @ 30Hz = 900 RPM (" ")
120 @ 15Hz = 450 RPM (' ")
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Old 06-03-2008, 08:44 PM   #5
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110V-230V compatible electrical motors ??h?


Thanks for answers..... First.. The charger.... It looks like the fuse is situated first in line after the powercord "intake". It said 5A 250V. Shouldn't it then tolerate 240V with no load through the fuse (Only load was multimeter measuring voltage over output pins) Nothing els looks burned inside, and it took a while for the fuse to blow... Think I'll try a bigger fuse and see what happens. I'll come back to it if it's of interest.
Just one concern.. I would like to know the right voltage at the output pins of the chargers. Does anybody have a bosch 7,2-24V NiCd charger??? or other manufactorer with same output voltage rating. I didn't expect the charger to work, but now I'm curious if it will..........

Electric motors.... guess most handtool motors have brushes, ergo not Hz sensitive.. What happens if you double the voltage. Do you half the current draw or do you double the wattage (run faster??)
I work much of the time in the montains where the voltage tend to be a bit low. An electrician said it could be bad for the tools, because they ran hotter. Don't know if he ment because of lower speed and thereby lower fanspeed, or maybe they draw more current to do same work and get hot because of that (wires, windings etc)..
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Old 06-03-2008, 10:46 PM   #6
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110V-230V compatible electrical motors ??h?


All electrical devices are designed to be operated at their nameplate voltage. Most of the time, the range is + - 10%. If you exceed 10% over the nameplate voltage, the device is very likely to be destroyed. (Remember the pipe example?). Some devices can tolerate less than -10% of nameplate voltage (like a light bulb or a heater), but they don't work very well.

If ANY 120 volt device is connected to a 220 volt source, it will be destroyed, usually quickly. If a fuse blows, the reason is because too much current tried to get through. If the fuse is replaced with a higher amp one, something downstream from it will blow. Like a circuit board. Or a transformer. Or a wire, that likely starts a fire when it blows. If a 120 volt power tool is connected to a 220 volt source, the current will not be 1/2. In theory, it'll be twice as much. Twice the voltage + twice the current will certainly burn something up.

Rob

P.S. Almost all handheld power tools have universal (brush type) motors. If this type of motor is operated at a lower voltage, it runs slower and produces less torque (power). The main reason they run hotter is because the operator lugs it down more, and while the actual current is a bit lower, because of the lower speed the fan doesn't cool it enough. If such a tool is designed for 120 volts, and is run with 220 volts, it'll run MUCH faster, but only for a very short time.

Rob

Last edited by micromind; 06-03-2008 at 11:00 PM. Reason: Added P.S.
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Old 06-06-2008, 01:25 PM   #7
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110V-230V compatible electrical motors ??h?


Aren't we talking about a battery charger & not the electric motor? The OP has a battery powered device, which is not driven in any way, by the supply voltage.

Nonetheless, it sounds like the "battery charger" can't handle the input voltage. It should be very easy to build/buy a battery charger to suit the OP's needs.
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Old 06-08-2008, 10:58 AM   #8
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110V-230V compatible electrical motors ??h?


OP's Quote: What's the difference of a 110V 60Hz and a 240V 50Hz electric motor,

Thats why I did include motors as examples.
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Old 11-03-2008, 09:11 AM   #9
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110V-230V compatible electrical motors ??h?


Hi,

I'm going to make a boiler for solid fuels work in Alaska. The problem is, it 's from Poland (my homeland) and it works on 220V 50 Hz compared with Alaskan 110V 60 Hz. I'm going to use a 1000 W Watt 110V - 220V Voltage Converter Transformer. Is this a good idea?
Thanks in advance.

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