[time-nuts] NTBW50AA Power Consumption

[Bob Camp]

Hi

Ok, I'd agree that there is a slight advantage to running 24 volts instead of 48 volts. I don't think I'd toss out a 48 volt supply setup, but if you're buying a new supply 24 looks like the better choice.

Bob

On Sep 10, 2013, at 5:48 AM, GandalfG8 at aol.com wrote:

> I've monitored the power input against voltage for a couple of the uncased  
> versions of these units, both fitted with Datel TPB-5/5-12/1-Q48 power  
> converters and both well "warmed up", and it does increase somewhat with  
> increasing input voltage. 
> 
> On both units the input power to the DC to DC converter is  approximately 
> 500 to 600 mW higher at 48 Volts than it is at 24 Volts, just  for reference 
> that was with an ambient temperature of around 23 to 24  degrees C, and the 
> change does seem to be reasonably linear with respect to  voltage.
> As would be expected there's very little change in the output voltages so  
> this does represent extra dissipation within the converter itself.
> 
> Using identical Motorola patch antennas one unit consumes approx 6.30W  at 
> 24V and 6.85W at 48V with the other consistently 200mW lower across the  
> range.
> Switching over to a couple of Symmetricom timing antennas, for  example, 
> increased the input power in each case by approx 200mW.
> 
> This does suggest there is actually some benefit to be gained by  running 
> them at the lower voltage, but if this sort of  difference really becomes all 
> that significant then perhaps it might  also suggest a need for heading 
> back to the drawing board:-)
> 
> Regards
> 
> Nigel
> GM8PZR
> 
> 
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