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Low voltage transformer issue

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Posted by jaimslaw (My Page) on
Tue, Oct 25, 11 at 21:17

My vista 600 watt low volt transformer rings out at 12.5 volts at each if the 12 volt multi taps. My readiing at one fixture 85 feet away on 12/2 also reads 12.5. Input to he transformer reads at 118.

Question: is this an indication of a faulty transformer? I shouod see some voltage drop on a run like that as well.

Is tis a sign of a faulty meter?

I would that that no matter what the input voltage is, those taps should be outputting at an even 12 volts, not 12.5.

Very perplexed. Would not want to return the transformer. Its brand new.

Help?

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RE: Low voltage transformer issue

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"I shouod see some voltage drop on a run like that as well. "

Voltage drop only occurs is current is flowing.
Most meters are high enough impedance you would see almost no drop over the distance you have.

Voltage drop is the current (amps) times the resistance of the path (ohms).

No current, no drop.

An unloaded transformer ALWAYS measures higher than it rated voltage.
There is no current flowing in the secondary that acts to lower the output voltage.

Transformer outputs fall in voltage as the current they are supplying rises.

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RE: Low voltage transformer issue

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Thanks for your expertise. I did test the line voltage st the end of the run, only this time, i had the bulb in and sure enough, voltage was 11.5 VAC. All of the landscaping tips tell you to test the voltage ag the end ofthe run, but fail to mention that testing should be under a load, not just touching the bare wires.

So you are spot on with your reply. Again, thanks for your input.

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