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Wiring up a variac

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Hello,
I have to wire up this Variac and don't want to screw up with this High Voltage. The Variac takes in 230VAC and voltage output should be variable from 0 - 280VAC. The model I have is the 6020CT. According to the Data sheet the input for my configuration should be terminal 4-1 and output on terminals 4-3. Any info will be appreciated on how to do this safely.
https://www.electro-tech-online.com/custompdfs/2013/02/vt6000.pdf
My emphasis.

If that's the rotation you wish, then the terminal selection is correct.

AS TO SAFETY:

These variacs are completely electrically exposed and, as a result, pose an extreme electrocution potential. If you are not aware of the precautions needed to wire up such devices, seek qualified assistance before doing so.
 
The one thing ODD about Variacs is that the wiper is fused, not the input. This is VERY important. The general idea is that the transformer is rated for X amps, so the wires on the secondary are rated for a certain current. For an example lets say 10 A, 240 V. This would be 2400 W and lets say the primary is fused at 10 A. (the wrong way). Now draw a secondary power of say 10 V and 20 amps. That's only 200 W. But the 20 A rating of the transformer is exceeded. Therefore, you have to fuse the wiper.
 
actually, it's not that odd when you consider that the current the wiper is fused for is determined by the amount of current the wire in the winding can handle, which remains the same for ANY voltage. for variacs that have been operated unfused, you will often see all except the last 10% or so of the winding has been darkened or burnt. this is because somebody was thinking in terms of a traditional transformer instead of an autotransformer. in a regular transformer, the output current vs the input current is an inverse proportion to the turns ratio. in an autotransformer, the input current is equal to the output current
 
............................... in a regular transformer, the output current vs the input current is an inverse proportion to the turns ratio. in an autotransformer, the input current is equal to the output current
I believe what you mean is that the maximum output current can be no more than the rated maximum input current. Certainly the autotransformer otherwise follows the standard transformer rule of Input VI = Output VI. If not, there would be a lot of power dissipated in the transformer at low output voltage settings, which is not the case. :rolleyes:
 
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yeah, i guess that was a poor choice of words.... what i was trying to say is that if the variac is rated at 2.5A, you can't get 10A out of it with it set at 25% of the input voltage, the max output current is still 2.5A.
 
As mentioned before, the exposed wires and contacts make this potentially very dangerous to own and operate. I HIGHLY RECOMMEND you build some sort of case for it. Acrylic, wood, or other types of plastic are ideal. You really can't go too far wrong though, when this sort of voltage and current is on the line. If I were you, I'd seriously consider purchasing or building a case before using this thing.

Good luck!
Regards,
Matt
 
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