Transformer question

[shon35us]

Am I going crazy?? I have a 36 volt center transformer,. So I should had 2 18 volt ac output right?

But for some reason I measure 21 volt ac on each output?
Can some shed some light this for me, and by the way this the 3 one I have tried 2 of them were used.

Lost

 

[pooge]

You are measuring "no load" voltage. If the transformer outputs its rated current, the voltage will drop from no load voltage. Also, your mains supply may have a higher voltage than what the transformer specifies for its rated output.