Replacement transformer no longer exists!?

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Old 10-01-13, 08:17 AM
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Replacement transformer no longer exists!?

I have a 4 bulb halogen vanity light which has a burnt out transformer. The transformer is a LIGHTECH LET 151 DC 150 watt also on the label LDC. Input 120V 50/60Hz 1.25A ....11.5V Output 12.5A. Trouble is I can not find a replacement. Seems like everything I find is AC? This unit measures 4.5 inches by 1.75 inches by 1.5 inches. and there is not much room to change that going larger. If I have to install a larger one, I will find a way to hide it. Any help would be appreciated.
 
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Old 10-01-13, 10:56 AM
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Welcome to the forums!

Seems like everything I find is AC?
That may be because a transformer steps voltage up or down without changing the nature of the current. The device you're trying to replace, which converts AC to DC, is called a rectifier. That doesn't mean that people, including people in the industry, don't call them transformers all the time.

Here's one that looks close: LET 201 AC (12V/200W) Halogen Lighting Transformer
 
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Old 10-01-13, 11:17 AM
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Given the cost of a transformer and the heat of halogens have you considered a new LED fixture?
 
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Old 10-01-13, 11:32 AM
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Here's an exact replacement for your fixture.

DC Lightech Electronic Transformer 150 Watt 12 Volt DC | eBay


Also available, different source same original manufacturer. (little more expensive)

LET 151 DC Halogen Lighting Transformer - Discontinued


Slightly different model number but same mfg. Will also work for you.

LET151R (12V/150W) by Lightech
 
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Old 10-01-13, 12:23 PM
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PJmax,

Thanks so much. Found the one on ebay, lifesaver. The last one you posted LET151R (12V/150W) by Lightech is actually AC.

So here is the main question. As this is a halogen fixture working on an AC system, do I really need to go DC at all? Wouldn't AC work? Does the halogen bulb know the difference between AC and DC?

Also good suggestion regarding getting LED regretfully one of two very expensive fixtures, so swapping fixtures is last resort.
 
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Old 10-01-13, 12:29 PM
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AC DC does the 12V bulb really care?

So I had always been under the impression that 12V systems were DC as in a car. So my eduction level is showing. Big question is this once the current has been transformed from 120V to 12V does the halogen bulb really care if it's 12V AC or 12V DC?
 
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Old 10-01-13, 12:44 PM
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Actually it should work okay on either. Of course the bulb on AC will experience brief transient voltages higher then 12volts (peak inverse voltage) but if the bulb is rated for AC that should not be a problem

.
Can a halogen lamp operate on AC and DC?
Yes, the halogen lamp doesn't differentiate between whether the power source is AC or DC, as long as the potential is 120 Volts. However, when the lamp fails, the filament will break and may draw an arc. You need to fuse properly for this event.
Source: teklight.com

So you may need to add a fuse to protect the transformer.
 

Last edited by ray2047; 10-01-13 at 12:53 PM. Reason: Add Ifo
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Old 10-01-13, 01:10 PM
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As with any incandescant bulb they work with either AC or DC.
I have used automotive ( 12 volt DC ) lamps with landscape transformers ( 12 volt AC ) with no issues or shortened lamp life.
In an electric generating station I did some work in they were using standard 120 volt incandescant bulbs ( commonly used in homes at the time ) on their 120 volt DC supply.
 
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Old 10-01-13, 02:37 PM
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Many thanks

PJ, Canuk, Nashkat and Ray many many thanks for your replies. All helpful. Solved the problem and enlightened me.
 
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