[Hammarlund] A Hammarlund Clock Motors and Rotors

[Roy Morgan]

At 01:21 AM 12/16/03 -0500, Barry wrote:

>A possible correction -- the rotors in the Hammarlund clocks may well be
>3.6 RPM -- a popular configuration, not 1 RPM.

Would be motor replacers,

Here are some critical factors that matter when selecting a replacement 
clock motor:

1) the physical shape/size/mounting of the thing
2) the RPM
3) The direction of rotation.
4) the gear or pinion on the shaft

>I seem to remember it as 3.6, but it's been a while.

You need to get this sorted out before you order a motor. You may not be 
able to return any electrical thing to the supplier.

>  You can check by
>marking one tooth on the gear on the rotor and manually rotating the
>works -- or if someone knows, that would help.

This may not work (turning the mechanism by the setting knob to find out 
how many revolutions are needed at the clock driving shaft/pinion) 
because:  the clutch that allows for setting is normally in the works at 
the hand driving gears, not in the motor..  Usually you cannot move the 
output shaft of a motor at all because of the gear reduction inside the 
motor case.

>The rotor is not special to 24 hr. clocks.  That's done with the gearing
>of the rest of the mechanism.

Agreed.

Notes:

1) old clock motors often sound loud because they are worn out. You can 
expect any new motor to be almost silent.

2) Any one who finds a source for replacement motors for the "Numichron" 
24-hour numeric readout clocks so common in shacks of old, and also used in 
the Heath SB-630 Station Control, gets a reward from me.  (Reward: I'll 
replace the motor you buy or pay for in your clock, and do modest repairs 
to whatever the thing is.)

Roy
who did clock repair a long time ago

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
roy.morgan@nist.gov --