Toroidal transformer voltages - sanity check needed!

[m_c]

Just got the new toroid in place, and it's giving me 44V. Slightly lower than what I ideally wanted, but still 8V higher than the previous, so I should be able to eek a little bit more speed out the steppers.

[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.