[time-nuts] Three HP oldies

John Howell j at howell61.f9.co.uk
Mon Mar 12 16:20:41 UTC 2012


I'll second that Rob!

I have the HP 115BR and, what I believe to be a British version made for the Royal Navy by McMichael. Pictured here:

http://www.flickr.com/photos/75ohm/6829984174/ 
and here
http://www.flickr.com/photos/75ohm/6976111697/

Called a 'Clock Direct Reading' & carrying NSN 6645-99-972-5270 this incredibly well made device requires a 100KHz input which is divided to 1KHz. This powers a Muirhead motor with an armature speed of 10,000 RPM. This is then geared down to drive a mechanical digital readout. The display can be advanced or retarded using a handwheel which operates a differential gear in the drivetrain. There is a 'pips' output which is 100mS of 1KHz every second.

I would be most interested to hear from anyone with information about this device, how and where it was used, circuitry etc.

John Howell (in the UK).

 
On 12 Mar 2012, at 10:36, Rob Kimberley wrote:

> Lovely stuff!!
> Rob
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Pete Lancashire
> Sent: 11 March 2012 17:56
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Three HP oldies
> 
> 101A
> https://plus.google.com/u/0/photos/111617808980322733757/albums/571869450289
> 0226481
> 
> 115CR
> https://plus.google.com/u/0/photos/111617808980322733757/albums/571869789245
> 1866241
> 
> 116AR
> https://plus.google.com/u/0/photos/111617808980322733757/albums/571869946252
> 1152657
> 
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