Torrid VA ratings, does too much juice hurt?

Hi Guys,

I have a silly question...

I am needing to get a torrid for an SSL comp and need a 15-0-15 and the
parts list says around 25VA. I can have one manufactured locally, but the VA
ratings they do are 50VA and 70VA in that power range.

Is there any danger in having more juice than you actually need, aside from
the fact that physically it is a larger trano. I suspect there is not need
to worry, but wanted confirmation from those in the know.

Alternatively has any one used a torrid from either RS or Farnell (220V)?
Does anyone have the part no handy, is there a partic. brand that is better
than others?

Thanks in advance

Matt

Hi Matt,

In general, the only problem with over-sized transformers is their somewhat-larger iron loss, which translates into a bit more power consumption - and in rare cases they will be a bit more noisy (mechanically and stray-field wise) than small ones.

In a circuit like the SSLClone, there are no parts that are sensitive to induced noise, so anything goes really.

After all, this board was originally designed with an on-board non-toroid power transformer - and these are orders-of-magnitude more electrically noisy than even the largest toroid you can fit into a 19" box..

Jakob E.

Hey Jakob,

Thanks as always :thumb:

I love this place :green:

Cheers

Matt

Matt, I used a 80VA transformer / 230V primary from RS - in Germany it is part nr. 223-8673. Actually I wanted a smaller one, but they didn't have it in stock, so they sent me this big sucker. Working fine, so far!!

And there will be an advantage to the larger toroid in terms of less radiation on the diode charging current spikes, as you will be less likely to be saturating the core. When the core starts to "go away" toroids radiate all too efficiently.