[ARC5] Vibrator Power Supplies

[Brian Clarke]

Hello Les,

Saturation is only related to primary Voltage - or more accurately, 
magnetising current, which depends on the primary having sufficient 
inductance; hence, the mag current is mostly reactive, because a good design 
will have low primary resistance to reduce copper losses. The load affects 
the amount of VAr as a proportion of the total primary VA.

A far better piece of data gathering would be to sense current and Voltage 
on a CRO under two conditions, as Les has suggested:
1. changing load
2. changing primary Voltage

Read them as X and Y so you can see the phase relationship.

73 de Brian, VK2GCE.


On Sunday, December 09, 2012 11:18 AM, Les offered:


> An addition to Roy's experiment:  measure the primary current as the
> primary winding voltage is increased.
>
> (1) Set the subject transformer up with rated load and fed from a
> variac.
>     Plot primary winding current vs primary supply voltage.
>    Estimate working voltage as 85% of the voltage where the current
>    falls over the "knee" of the input I-V voltage.
>    Alternately, estimate the point at which the I-V curve deviates from
>    a linear response.
>
> (2) Repeat, but w/out load.
>
> Compare the loaded and unloaded results to estimate the value where
> saturation begins.
>
>
>  Les
>  vk2bcu at operamail.com