[time-nuts] HP 5370B dropping mains voltage

Jim Lux jimlux at earthlink.net
Sat Jul 6 17:50:25 EDT 2013


On 7/6/13 2:39 PM, Mark C. Stephens wrote:
> How Does that Work Robert?
> I mean why out of phase?

Then the voltage on the secondary of the buck transformer is subtracted 
from the line voltage.

This is a very common thing commercially where you have what's called a 
"buck/boost" transformer to adjust the line voltage.  Typically to boost 
it at the end of a long run where resistive drops make the voltage too low.

The low voltage secondary must be big enough to carry the entire load 
current, of course.


>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Atkinson
> Sent: Sunday, 7 July 2013 12:57 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] HP 5370B dropping mains voltage
>
> Hi Marki,
>
> Dropping the mains voltage is easy. Get a mains to low voltage transformer. Connect the primary across the mains and the secondary in series opposition (out of phase) with the mains supply. Foar example a 100VA 12V transformer will drop your mains to just under 238V with a maximum load of 8A (the current rating of the secondary).
>
>
> HTH,
> Robert G8RPI.
>
>


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