Electrical transformer output questions

flying_fish

I have what I hope is a simple question....

I have an excerise bike that uses a power transformer, which I have lost. From the wonders of google I think its a transformer with an output of 12V and 1 amp that is used.

However I have now got to the limit of what I can find on Google as I am not I am not sure if it is DC or AC output needed, or is this a silly question? There is also a reference to polarity with transformers, what is this? Do transformers always give a DC output, or are AC -> AC transformers also available?

If I have to take a guess on AC or DC, which is it likly to be? Will trying the wrong one result in my frying anything?

Thanks

timbim_2

It might say on the bike what input is needed, I'd guess that it'll be 12V DC, you really don't see stepped down AC in. If it's got polarity markings anywhere, then it's definitely DC, AC has no polarity.

Mr_Oink

Actually it's quite common to see step down AC. Many DSL routers being a point in hand :-) Something I discovered when trying to knock up a portable DSL tester that ran on batteries...

I suspect with an exercise bike it's probably going to be in the order of 6-9v DC with a reasonable amount of current. Looking at my cross trainer and exercise bike one is 6v 500ma DC , the other 9v 500ma DC.

Hope that helps

Debian is an old English word meaning 'Slackware is too hard for me'

flying_fish

I have just had another had a good look on the bike, and I cant see anything on it that tells what input should be. Also I have opened the guards, and had a look at the circuitry. The power appears to enter, then into a circuit with a few resistors and capicators, then directly off to the windings for the resistance control, and to the display. Also the bike has an electromagnetic brake system, so would that mean that the current to the resistance control is DC?

Owain_Moneysaver

Make and model of the bike? Possibly the instructions say what power is required?

flying_fish

Its a Tunturi E3. The manual can be found on google (I am not allowed to post link), however it doesnt give any info about voltage.

If I take a guess as 12v DC and it is incorrect, is it going to result in burning out anything?

Stompa

FWIW here:

http://www3.btwebworld.com/cgi-bin/listprod.cgi/tstl

it says: "Operating voltage 230/110 V, 24 V DC transformer".

flying_fish

Thanks very much! I spend ages searching and didnt find that!

One last question... what about current? Does it matter if I go for a high rating one?

Hammyman

flying_fish wrote: »

I have what I hope is a simple question....

I have an excerise bike that uses a power transformer, which I have lost. From the wonders of google I think its a transformer with an output of 12V and 1 amp that is used.

However I have now got to the limit of what I can find on Google as I am not I am not sure if it is DC or AC output needed, or is this a silly question? There is also a reference to polarity with transformers, what is this? Do transformers always give a DC output, or are AC -> AC transformers also available?

If I have to take a guess on AC or DC, which is it likly to be? Will trying the wrong one result in my frying anything?

Thanks

A transformer will always output AC. That then goes into a circuit which rectifies it to DC and regulates it.

If you're talking about a power supply, it'll be a DC output. You should see something on it saying the output voltage. There'll be a symbol there as well:

This means DC:
____
_ _ _


This means AC:

~

KillerWatt

flying_fish wrote: »

One last question... what about current? Does it matter if I go for a high rating one?

Won't make any odds if the replacement can deliver more current, the bike will take what it needs and that's it.

Polarity will be important though, get it wrong and the risk of damaging the electronics is quite high.

flying_fish

@ Hammyman - Problem is that I dont have anything to look at to determine if its AC/DC or its polarity. There is nothing on the bike that gives this info, or in the manual. Only info I have is the link that stompa has found.