Changing secondary voltage (Uncivilized way)

[Nikon1975]

Question: I have a transformer 400-360-0-360-400 in a PSU I use for testing.
To switch between the 400 V and the 360 V, can I connect the rectifier to the 400 V taps and put a switch between the 360 and 400 V taps ?

When the switch is close it will work at 360V, when open at 400V.

Am i missing something ?

Thanks,

Davide

 

[chrish]

Why not use a DPDT (dual pole dual throw) switch and switch between the two 400 and 360 volt taps?

 

[stevecole]

You certainly CANNOT use your initial suggestion, as you will be shorting out 2 sections of your transformer secondary, which will fry it pretty quickly. The Double Pole Switch is a better idea, although still with some risk, as there will be rather a lot of voltage between adjacent poles of the switch. A safer option would be to terminate the secy's on suitably rated terminal blocks (one for each phase perhaps) and then select the ones you require with a link.

 

[tomchr]

If you can find a DPDT relay that can handle the voltage and current involved, I suggest switching between the two taps that way. I would not want 800 V present at some front panel switch. Note that the unused tap on the transformer secondary needs to be floating when not in use - hence the need for a DPDT (double pole, double throw) switch.

~Tom

 

[Nikon1975]

OK, got the point, bad idea
:-(

D.

 

[Richard Ellis]

When working with switches there is another specification in addition to Voltage rating and current rating....that is:
"make before break"
AND
"break before make"

________________________________________________Rick....