Transformer.

[davethebirdman]

Hello Everyone

I'm now in the market to replace the old transformer that ran my unit. I've looked all over for markings but can't find any. Could someone plse tell me what rating, Voltage & power the unit would run on so that I can buy the appropriate stepdown transformer.

Thanks

Dave

[johnieG]

Quote (davethebirdman @ Dec. 08 2005,10:34)

Hello Everyone I'm now in the market to replace the old transformer that ran my unit. I've looked all over for markings but can't find any. Could someone plse tell me what rating, Voltage & power the unit would run on so that I can buy the appropriate stepdown transformer. Thanks Dave

Again, that depends on what voltage your machine is set for, I assume it's from the U.S. & is wired for 120Volts A.C./50-60Hz (Cycles), so you'd need a step-down(from 220 to 120) transformer of the appropriate V.A (volt-amps, simular to Watts, but for A.C. power transformers) take the voltage used by the unit & mulitply it by the current in amps, this will give you the approximate V.A. so, for say as an example 120Volts at say 12amps...then]120Volts@12amps...then

   120
x    12
-------
1440 V.A. or 1.44 K.V.A. (kilo/volt/amps) THIS IS ONLY AN EXAMPLE, check your nameplate on the side of your machine, or someone else machine, it should list the total amps on the plate...

I would remind you that electric motors pull more amps on startup than when running, so, for this example,I'd go with at least a 2000VA./2.0 KVA unit. hope this helps you out...JohnnieG

[davethebirdman]

Hi Johnie

Thanks for your words of wisdom.

I have found the plate and its 115V 60cycles 1 PH 26 amps. The plate matches up with the freezing unit. So

115 x 26 = 2990 VA. That's right I hope.

I have looked at the website I want to get the transformer from and the highest they do is 3000. They do have a guide

http://www.airlinktransformers.com/transformer-guide.asp

Where the recommend 300 for a fridge and 1000 for a fridge/freezer. Elsewhere they are talking about running huge ammonuts of equipment on 3000.

Am I going mad???

Thanks

Dave

[johnieG]

I'd say your getting there... , 26 amps is way too high!, I think it should be/read 2.6 amps,you're missing a decimal point somewere, the line cord is only 14 gauge/awg at best, that would be rated for 15 amps typically, the line cords on these old machines is only usually 16-gauge/awg that would suffice for about 10 amps/max. (26 amps would require 10-gauge/awg at least!)

A typical 1/4 h.p sealed compressor at 70 degrees-F /120 volts should run about 235 average watts/1.95 amps,  and at startup about 1250 peak watts/10.4 amps . so I'd say about a 1450 VA unit should do ,as I belive that your C-51 has a 1/5 h.p compressor & a 9 watt evaporator fan, the 1/5 h.p. units actually pull a little more current than a 1/4 h.p.

[globalcompressors]

Guys,

Also keep in mind that we are on a 60 cycle system vs. 50 cycle abroad.
This will also make a difference when trying to make an appropriate decision
on how much wattage will be needed. You need a larger transformer to
compensate for the lower voltage. I'm not an electrician but when selling air
conditioning compressors to Africa, 50hz, it was an important issue, especially when
referring to start up or cranking amps.
Just check and make sure!

Eric '>

[johnieG]

You are correct Eric. the lower the frequency (hz*)  the more of a "load" it puts on an electric inductance motor. if a motor is rated/designed for operation at 60hz/(cycles per second) it will tend to draw more current & run hotter, when running on a 50hz power supply/power-grid , same goes for tranformers.

if you look at your machines electrical spec's plate, it will specify what rate (hz) the motor/compressor is rated for, on earlier models. it's almost always only 60hz, sometimes listed as "60-cycles" , most modern motor's have a dual rating of 50/60 hz, so they are designed to run on either. when in doubt, research is cheaper than trial & error!  :'>

so what does this mean in Dave's application, he'll have to add a little extra "head room" (wattage-rating) to the stepdown transformer to compensate for the higher start & run draw (amps) of the compressor & evap' fan motors on 50hz/220V A.C. in England, (which I kinda figured into the suggested KVA the rating of the stepdown transformer without thinking about it anyway.)mmm... brain-food!

plus... he can always check his application with his electrical supplier. remember, the only dumb question is "honey...where's the fire extinguisher !!?"  

[globalcompressors]

You are full of great info, John!!! I knew about the newer equipment having the
duel rating. I just wasn't sure how to get there, the way you did, on older
machines.   See....you CAN teach an old dog new tricks!  

Someone please tell that to my wife...  Ruff, Ruff


Eric '>

[davethebirdman]

Eric & Johnie

Thanks for your thoughts. All this technical stuff, makes me wish I'd paid more attention when I was at school.

Cheers

Dave

[MoonDawg]

Quote (davethebirdman @ Dec. 08 2005,7:34)

I'm now in the market to replace the old transformer that ran my unit.

Why replace it?

[davethebirdman]

Well

Its old and I'm not too sure how long its been lying around. It did seem to work the fridge okay. Longest I had it running was overnight.

If I was to get someone electrical to have a look at it just to make sure its sound it would probably cost me the same sort of money as it would to replace it. I have this great fear of electricity. A fear of the unknown.

BTW - I have made some tentitive enquires here about getting a drum for the V-39 made up to vend cans and the costs are way off the scale. What I think I might do is just enlarge the hole on the bottom plate so that it can take longer necked bottles. I'd be interested to know if anyone has ever done this themselves.

Dave

[BrianB]

Transformers are typically either good or bad. You can measure the input side primary and the out put using a multimeter. Usually, if you have between 800 ohms and 1K ohms (on the high side), it's good to go. If it's lower, you can either replace it, get it rewound or use it till' it croaks on you and then replace it.

[davethebirdman]

Hi Brian

thanks for that. The unit seems to run okay I was just a little concerned about the fire hazzard side of it all. Its old with old wiring running out of it that will need to be changed anyway. I might give it a go for a while to see if I can get life out of the old fella. I just don't want it to repay me by setting fire to the curtains and all the kids Christmas pressies.

Dave