Re: [CAD_CAM_EDM_DRO] Re: power supply

Mike Snodgrass wrote:

> Bummer! it seemed like a good one. Is there another way to trim the
> voltage other than huge , hot, nasty, power resistors or bulky variac?

Power resistors will not "trim the voltage", either. They will cause a voltage drop
that varies with current draw.

There are voltage adjusting transformers (usually autotransformers) available for
converting 208 - 240 and 240 - 208. These are often used to run 240 V
air conditioners, or other mid-size motors, in locatins where 120/208 3-phase
power is the only thing available. You should be able to find them at air
conditioning parts shops and electrical contractor suppliers. Because the core
only needs to handle the difference Volt-Amps, these transformers are quite
small. About a 4" cube, weighing maybe 6 pounds. I don't think they are
expensive. I'll bet Grainger has them, too.

You can cut your voltage to 86% of what it is without the transformer.
You'd wire the line input (either 120 or 240 V) to the terminals marked
240 V and the power supply would be connected to the terminals marked
208 V. If you were supplying 120 V to your transformer before, it would
now see 104 V. This should help bring your ~80 V down to 69 or so,
safe for the Gecko.

Jon