PT current in AC or DC?

[Guitarxtc]

I don't understand this part of power transformer current ratings, i always see on Hammond,Edcor and similar only like Center tapped 300-0-300V 0.200A or 0-300V 0.200 A but on Hashimoto Power transformers they label current in AC and DC like on photo. can someone explain this?

Screenshot 2022-01-19 at 22.26.34.png

[mhuss]

They're probably providing the useful DC output current that can be expected using the transformer with the normal rectifiers and caps, etc. In some ways that's more useful then the AC spec, which as your sheet demonstrates is usually different than the actual DC current it can supply.

[martin manning]

....on Hashimoto Power transformers they label current in AC and DC like on photo. can someone explain this?

The relationship between between AC current supplied by the transformer and rectified DC current varies with the rectifier and filter type. This page from Hammond shows what the current ratios are for various configurations. http://www.hammondmfg.com/pdf/5c007.pdf

[pdf64]

There looks to be some dodgy info on that page.
eg the IAC of a 2 phase cap input rectifier should be greater than IDC.
And V average for smoothed DC types isn’t defined.
There must be a better resource on the net for that type of stuff?

[Stevem]

Yup, it's nice to have those rectified DC numbers!

[pdf64]

Yup, it's nice to have those rectified DC numbers!

But in reality, the IAC is dependent on the reservoir cap value.
It seems a bad idea to mix up typical currents (which seems what the IDC data must be) with max rated currents.
And, for the 2 phase rectifier intended types, why isn’t there a consistent relationship between IAC and IDC?

[Phil_S]

Good points are being made all around. I think we should take the Hammond sheet for what it is -- a general guide, something better than OK, but less than perfect. It's still useful information. Just don't try to tax the transformer to its maximum limit.