[ARC5] Vibrator Power Supplies

[Kenneth G. Gordon]

On 7 Dec 2012 at 8:35, Robert  Eleazer wrote:

> Two questions:  
> 
> 1.  Why did they not use vibrator power supplies instead of dynamotors
> in WWII?  They ought to be cheaper and easier to build.

Dynamotors are more reliable and output "better" DC. Have you ever 
examined the DY-88 closely? It is a combination of dynamotor for the 
transmitter and vibrator for the receiver.

> 2.  I have the transformers out of an old RCA Carfone vibrator power
> supply.  Tried to make a DC power supply out of them.  They do not
> work all that well with 115V 60Hz on the secondary.  Anyone know why?

Yes. It has to do with the number of turns per volt and the amount of iron in 
the transformers. They are designed to have pretty high hysterisis to keep 
the spikes down. This is opposite to what you want with a 60 Hz sine wave. 
For a straight 60 Hz sine-wave power supply, you want the hysterisis to be 
minimal and the transformers are designed to provide that.

I suspect that the frequency of operation has something to do with it too.

Ken W7EKB