Toroidal transformer voltages - sanity check needed!

[russell]

If that's at nominal mains voltage it will give you over 48 V at the maximum of +10%; I wouldn't want to go any higher. Did you measure the mains voltage when testing?

Russell.

[m_c]

No.
I seem to have a lack of insulated proves for the multimeter just now, so just measured to make sure the voltage wasn't too high. The Gecko's are good for 50V, so a 6V safety margin should be good enough.

[russell]

You are probably OK. However, the reason I asked is that the UK mains voltage is 230 V with a tolerance of +10%, -6%. So, if the mains voltage was 6% low when you made the measurement, then the voltage you get at maximum mains voltage will be over 50 V. An unlikely but possible situation.

Russell.

[JAZZCNC]

If it's for the Gecko G540 then this will do the job. http://www.airlinktransformers.com/t...with-leads.asp

I've just built a control box for someone using this toroid and It is giving a steady 47V and my mains input voltage is quite high due to the fact I live bang next to the sub station.
I've had it on test know for several weeks and no issues's so far.

EDIT: Doh . . . didn't read all the post's did I.!! . See your sorted.

[m_c]

Russell, you've got me curious now!
I'll have to go and find a multimeter with suitable clamps, just to satisfy myself.


Jazz, I'll keep a note of that, as I've got a couple other projects I'd like to do that may involve more G251s.

[russell]

Another thing to consider is: Did you measure it under load?

A transformer usually specified under full RESISTIVE load. So, when unloaded the voltage increases by the specified regulation figure. I guess you tested it unloaded in which case you are safe. Calculating the output voltage of a transformer/rectifier under mixed capacitive and resistive load is by no means easy. For a one off, your approach of try it and see is the best way.

Russell.

[stuboy]

If your still looking for any other caps I have a garage full! So can sort you out something appropriate for (hopefully) much less that RS or Farnell
Drop me a PM, that goes for anybody else that might be interested I guess.
Cheers
Stuart

I've just been searching for the extra bits, and have given up on the search for tonight.
Capacitor calcs work out at around 12500uF, and 63V seems to be the nearest, but neither RS or Rapid have anything suitable in stock.