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[#1] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
各師兄: 小弟在USA買了一部CD唱機是120v/60hz, 請問有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,
又若用變壓器可由220v/50hz轉120v/50hz可不可以, 會不會損壞CD唱機呢?多謝師兄指教!!!
hkf112233
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61.xxx.xxx.70
2008-09-21 12:28
[#2] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
Transformer 只能變壓,不能變頻。最簡單的可用一些on line ups , 可set op to 120v 60Hz, 另一些ac to ac converter 也可,但以你的机來說,找隻 stepdown transformer 可以用了, 60 hz 唔雖要理會。
epic
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203.xxx.xxx.93
2008-09-21 15:51
[#3] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
謝謝epic兄, 希望各師兄比多些意見,thx!
hkf112233
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203.xxx.xxx.18
2008-09-22 08:36
[#4] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
希望各師兄比多些意見, 及可否介紹一些變壓器的牌子呢, thanks!
hkf112233
個人訊息 會員
203.xxx.xxx.18
2008-09-22 08:40
[#5] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
epic 兄, 為甚60 hz 唔雖要理會?
hkf112233
個人訊息 會員
203.xxx.xxx.18
2008-09-22 08:46
[#6] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
epic 兄, why 60 hz 唔雖要理會?
hkf112233
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203.xxx.xxx.18
2008-09-22 14:39
[#7] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
一樣工作的, 至多隻牛有小小震或輕微 de de 聲, 你亦可搬返去美國用呀, 咪唔洗轉啦
254mm
個人訊息 正式會員
218.xxx.xxx.9
2008-09-22 15:13
[#8] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
其實你去買隻轉壓牛, 個 sales 哥哥都會解比你聽, 幾拾元就知結果啦, around US $10 can know the answer already
254mm
個人訊息 正式會員
218.xxx.xxx.9
2008-09-22 15:16
[#9] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
"""why 60 hz 唔雖要理會"""

Because your cdp ultimately works on DC. No matter AC of what frequency is fed into it, it will convert it into DC, which is 0 Hz. The 120V transformer in your cdp might be designed for 60 Hz. However, in view of the small difference, it should also work perfectly fine on 50Hz.
thomasc2
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202.xxx.xxx.165
2008-09-22 16:22
[#10] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
Hi hkf112233,
Thomasc2 兄已解答了! Thanks!
一般用的 power transformer 的 frequency respond 絕對可隨意對應 50Hz or 60Hz 的 freq. 只因當地用 60Hz, 所以才 Label 60Hz,如廠方有出口的機種,也只用轉變電壓,再改個label便成, 只差 10Hz 的freq. 不會對機器做成傷害的!除非有些 equipments 係要利用到 AC 的 Freq. 去工作的則別論!
epic
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203.xxx.xxx.89
2008-09-22 17:32
[#11] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
some turntable using AC directly, 50hz must use 50hz, otherwise the speed will be faster.
hercules
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219.xxx.xxx.238
2008-09-22 18:15
[#12] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
yes,sure!

epic
個人訊息 正式會員
203.xxx.xxx.78
2008-09-22 18:48
[#13] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
Maybe I raise a point to discuss about a little bit more for the safety of a transformer between 60Hz transformer using in 50Hz country.

Theoretical from my memory the Turn / Volt of 50Hz designed transformer is about 12% higher than 60Hz, for small signal like CDP or some mentioned can be used in 50 or 60Hz of course no problem at all.

But for the power amp and just 60Hz mentioned on the transformer you better to monitor the temperature of the transformer.

The above just my 2 cents hope some transformer high hand can explain more.
et2
個人訊息 會員
124.xxx.xxx.200
2008-09-22 18:57
[#14] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
There are somethings you need to consider when using a transformer in different Hz even it is just for providing DC.
The maximum power of a transformer is mostly limited by the saturation flux of the iron core. The flux absorbs energy from primary coil and releases energy to the secondary. If the transformer works at a higher frequency, there is more cycle of energy transfer and the total energy passes is larger. That's why those computer switching power supplies need a tiny transformer (those PSU work at a frequency far higher than 50/60 Hz. The frequency is made by the SMPS controller IC). If you use a 60 Hz transformer in 50 Hz mains, the VA value is 5/6 of the original. For a CD player, it should not be a problem. For other power critcial device, the transformer cannot survive in long run.
hetzer
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219.xxx.xxx.3
2008-09-22 22:01
[#15] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
My engineering knowledge is limited as that's not my profession. But I would think if you change from 50Hz to 60Hz, the energy transfer is the same, except the "iron loss" will be more. To the best of my knowledge, my middle school teacher taught me there is "copper loss" and "iron loss" for a transformer. Copper loss is due to copper wire resistance. And iron loss is due to eddy current and vibration. Bad core material will have much eddy current loss and the transformer will get hot. But since we are only talking about 50Hz to 60Hz, effect shouldn't be too high, as we are not saying 50Hz to 1Khz. Otherwise we will all have problems when bringing US equipment back to Hong Kong...:-)
yukclee
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219.xxx.xxx.34
2008-09-23 16:58
[#16] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
most of tansformer factory quote the spec. of it transformer also specify 50/60Hz primary winding, whatever the capacity from 15 to 1000VA.
http://docs-asia.electrocomponents.com/webdocs/0111/0900766b80111b4e.pdf
epic
個人訊息 正式會員
210.xxx.xxx.118
2008-09-23 17:12
[#17] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
Interesting discussion!

Now, as you guys may know, the older PS Audio powerplants allow users to raise the AC frequency up to 120Hz (or so). While PS Audio claimed that this would charge the power capacitors better, what would 120Hz AC do to the power transformer of a power amp.?

thekong
個人訊息 會員
202.xxx.xxx.81
2008-09-23 18:00
[#18] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
Thekong hing,

Good example and question, I never tried the 50Hz or 60Hz TX worked under 120Hz environment, but for me, my answer is positive but not too much gain to use high frequency for the transformer from the electrical side.

Power - from ’hetzer hing’ you get higher VA value, but due to the size of the wire still remain unchanged so you can’t get much higher

Power Loss - from “yukclee hing” Copper loss still remain unchanged but you will get higher Eddy-current loss and Hysteresis loss. They also will generate more heat, but if the grade of the iron core is high such as same material of output Tx applied, those two losses will be minimized to a very low value.

But the other side is after rectifier, you can imagine the time interval in between P to P is shorten that means you got better DC source if your cap good enough, once you got better DC source I suppose you got better sound for the same condition.

Hope some brother tried before and let us know the result.
et2
個人訊息 會員
203.xxx.xxx.63
2008-09-23 19:38
[#19] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
首先,我相信在一般的 application 內,並不雖理會 50/60 Hz 對 equipments的兼容性,很多的牛廠都說明它們的牛能正常工作在 50 or 60 Hz的。很難找到一隻牛只能工作在50 or 60Hz的,應沒有廠家做這樣的牛吧!從發燒角度看,50 , 60 , 120 Hz 的 AC supply是對聱音有影響的。120Hz 我沒試過,我只試過用 on-line UPS 轉做 60Hz,但出來郊果我不喜歡,當然,這並不能代表 60Hz 不好,相信是 UPS 的問題!所以如一定要用60Hz 去operate 你的 equipments, 你所花費在 converter 的金錢也不小。
epic
個人訊息 正式會員
221.xxx.xxx.84
2008-09-23 20:07
[#20] 有冇師兄知有冇變壓器由220v/50hz轉120v/60hz,    
"""50Hz or 60Hz TX worked under 120Hz environment,"""


Would this be similar to using 3 phase electricity to power 2 phase equipments?
The result is that you would have smaller ripples after rectification. Theorectically this should be DC of better quality and therefore less demanding in respect to reservoir capacitors (as PS Audio claims).

thomasc2
個人訊息 會員
218.xxx.xxx.151
2008-09-23 21:32
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