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Homeowner Forum / Construction / June 2005Transformer for 110v power tools?
I have a bunch of 120 volt 60 Hz tools and want to use them with a 220 v 50 Hz supply. The highest current draw is 15 amp for a Milwaukee power saw. Curiously this saw's plate shows 120v AC/DC 15a - no mention of frequency. Does this imply a transformer power rating of 15x120 = 1800 Watts + some extra for power factor or whatever its called? I also have a Milwaukee drill that shows 120v 60Hz 500w, 4.5a Does any transformer stand out from the others for performance and price? Information appreciated. Thanks RF > I have a bunch of 120 volt 60 Hz tools and want to use them with a 220 v 50 > Hz supply. [quoted text clipped - 7 lines] > > Does any transformer stand out from the others for performance and price? A simple transformer will do the voltage conversion but not the frequency conversion. If you operate 60Hz motors on 50Hz they run slower (4000rpm becomes 3333rpm) and they run hotter and may not live very long. You can buy converters either rotary (eg a 50Hz motor driving a 60Hz generator) or solid state (all electronic, no moving parts) but they are likely to be be expensive if you need upto 2000W (2KW). A gas powered generator might be a cheaper if noisier option. You could try asking the maker but a typical answer for a motorised device.... Q: Can I operate my 60Hz freezer on 50Hz A: No! These units will not operate on the wrong supply frequency, attempting to do so may cause permanent damage and invalidate the warranty. Regarding the 120V AC/DC, I suspect the device uses an internal 'full wave rectifier' creating a DC source. Therefore it would not be frequency sensitive. You will still need a transformer capable of 50 Hz. In addition to devices who's speed is determined by the AC frequency, a 50Hz source spends a longer time per cycle above or below a given polarity. When the AC power goes through the transformer there is a likely hood that the magnetic core will saturate. When that happens there is no more resistance and you will get a current spike possibly burning out the transformer. A 50Hz source requires larger transformers because it requires a larger magnetic core. You might be able to use a 'Google' search to locate a 2:1 transformer capable of 1800+ watts, 50Hz for a 220/120 conversion. : I have a bunch of 120 volt 60 Hz tools and want to use them with a 220 v 50 : Hz supply. [quoted text clipped - 13 lines] : : RF > Regarding the 120V AC/DC, I suspect the device uses an internal 'full > wave rectifier' creating a DC source. I didn't spot that reference to DC first time but I'm inclined to agree with Mellowed. I think they are designed to work from DC welder generators. > 120v AC/DC 15a - no mention of frequency. The above means it will run on 120 volt Alternating Current (AC) @ 15 amps AND it will run on 120 volts Direct Current (DC) @ 15 amps As far as running the 60Hz stuff @ 50Hz. Kissem goodbye or please send the tools to me b4 you destroy them. Dan > I have a bunch of 120 volt 60 Hz tools and want to use them with a 220 v 50 > Hz supply. [quoted text clipped - 13 lines] > > RF Because the tools are AC\DC frequency is not an issue. Within the tool there is a rectifier.and the motor never see's anything other than DC.. > I have a bunch of 120 volt 60 Hz tools and want to use them with a 220 v 50 > Hz supply. [quoted text clipped - 13 lines] > > RF Thanks to everyone for the responses. I contacted Milwaukee and have had no reply yet. Will post it here when I get it. Thanks again RF > Because the tools are AC\DC frequency is not an issue. Within the tool there > is a rectifier.and the motor never see's anything other than DC.. [quoted text clipped - 18 lines] > > > > RF > Because the tools are AC\DC frequency is not an issue. Within the tool there > is a rectifier.and the motor never see's anything other than DC.. Well it sees rectified AC which isn't exactly DC. I guess they don't use capacitors to smooth it at 15A ? It is exactly DC, Pulsating DC but none the less DC. Electric current can be either direct or alternating. Direct current flows in the same direction at all points in time, although the instantaneous magnitude of the current might vary. In an alternating current , the flow of charge carriers reverses direction periodically. The number of complete AC cycles per second is the frequency, which is measured in hertz. An example of pure DC is the current produced by an electrochemical cell. The output of a power-supply rectifier, prior to filtering, is an example of pulsating DC. The output of common utility outlets is AC. Why bother with a capacitor? If it were an AC motor it would spend th esame amount of time at zero volts as the DC counterpart. > > Because the tools are AC\DC frequency is not an issue. Within the tool > there > > is a rectifier.and the motor never see's anything other than DC.. > > Well it sees rectified AC which isn't exactly DC. I guess they don't use > capacitors to smooth it at 15A ? Thanks JME for the interesting comments. Only one of the tools - the saw - is AC/DC, the drill is A.C., yet here's the reply I had from Milwaukee about the drill and power saw: "You can use the tools on a 120/ 50hertz system or 120/60 hertz system but nothing else. Please let me know if you have any more questions." More comments? TIA RF > It is exactly DC, Pulsating DC but none the less DC. > Electric current can be either direct or alternating. Direct current flows [quoted text clipped - 7 lines] > > Why bother with a capacitor? If it were an AC motor it would spend the same > amount of time at zero volts as the DC counterpart. > [quoted text clipped - 4 lines] > > Well it sees rectified AC which isn't exactly DC. I guess they don't use > > capacitors to smooth it at 15A ? Transformers equipped with appropriate plugs (get the right ones http://kropla.com/electric2.htm ) and receptacles are readily available. They call them power adaptors. I used one when I traveled to Europe. The transformers don't convert the frequency, of course, but most tools that work on 60 cps (Hz or hertz) will also work on 50 cps. The ones that rectify don't care at all. |||||||||||||||| Nehmo Sergheyev |||||||||||||||| Thanks Nehmo for the tip. Very useful page. I contacted Grizzly Tools and asked about using their 120v 60Hz motors with a 2:1 step down transformer that brings 240v 50 Hz to 120v 50 Hz and they say NO - should not be done. These machines have motors 1 to 2 HP. Wish all my tools and gadgets had rectifiers. I would think that all older tape recorders, VCRs, etc would not run properly on 50Hz. Epson said that my scanner should work fine on 50 Hz but they don't recommend it. Thanks again and enjoy the weekend :-) RF > Transformers equipped with appropriate plugs (get the right ones > http://kropla.com/electric2.htm ) and receptacles are readily [quoted text clipped - 5 lines] > -- > |||||||||||||||| Nehmo Sergheyev |||||||||||||||| |
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