Transformer Output...What is CTAP?...And VRMS??

charles4400

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What is CTAP?

I believe it is Center Tap but what does that mean? In this diagram is CTAP double the 18VAC so it is 36VAC?

CTAP_zpsahvbhbkk.jpg
 
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Ok thanks for clearing that up, I think I understand.... so in my first diagram, its a 36v transformer, but in the shown configuration the two outer terminals give 18vac and the center is neutral but if you only use the center terminal without the two outer ones, then the center is 36vac.? Is that correct?
 
In this case, yes, it is a 36VAC winding with a center tap.

This can be done for multiple reasons.... but some designs I've seen do a center tapped 15Vish winding into 2 diodes (one on each of the ends, with the common being the center tap, as opposed to using a 7.5Vish winding and using a full wave rectifier (4 diodes). There may be other benefits to the design than saving 2 diodes.... I'm not an EE, others here might no the pros of this design vs a non center tapped design with a full wave rectifier.
 
Thanks for the responses!

Ok one more question...

in this diagram when it says 36Vrms is that the saying the same as 18VAC as in my first diagram?

Vrms_zpsyn2ltxbn.jpg


I believe it is but just want to confirm before burning anything out...

This diagram is from Crusin Exotica in regards to the transformer giving power to the driver board.

The first diagram is of a Cruisn USA transformer going to its driver board.

So do both driver boards use the same power from the same type transformer? I belive they do but seeing 36vrms is throwing me off....
 
Yep, that is from that same transformer. The circled part is just showing you the corresponding pins on the connector.

I don't know why its notated differently in the two diagrams, but if it helps you visualize what's happening, you can measure the AC between the windings.

Blue/Black to Blue, you'll measure 18vAC
Blue/White to Blue, you'll measure 18vAC
and Blue/Black to Blue/White, you'll find 36vAC

"RMS" stands for "root mean square" and effectively means nothing at all, possibly that you can expect to measure slightly higher voltage unloaded?

Oxford dictionary of physics said:
For AC current, RMS is equal to the value of the direct current that would produce the same power dissipation in a resistive load.
 
Great thanks for clarifying that...the different notations between the two were confusing, if I were only looking at Exoticas diagram I would of just assumed it wanted 36v on each which would have been bad!!!

Thanks!
 
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