|
Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
|
Thread Tools |
5th Nov 2018, 11:30 pm | #1 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
|
Smiths ‘Bijou’ synchronous clock motor
I’ve had some experience and success with a number of Ferranti electric clocks, but my first attempt to repair a 1950s Smiths model CA alarm clock fitted with a Bijou motor has been a bit of a disaster.
A friend asked me to fit a new flex to his clock, but on test the motor would not self-start and seemed to lack torque when running. This motor is the later type with the external flywheel and hairspring. I measured the coil’s DC resistance at about 3.5 kilohms, which I think is rather too low as I’ve read that these are normally around 11k, so I suspected shorted turns. I attempted to gently part the two halves of the motor casing, whereupon the coil former fell apart. It looks like it had cooked and become completely brittle through overheating. “No matter”, I thought, “I can rob the motor from that other Smiths clock in the to-do pile.” After a spot of lubrication, this second motor self-starts reliably and its stator coil measures 11.5k. But its pinion has 8 leaves instead of 12... Hence I’m now looking for someone with the capability of creating a brand-new coil from scratch, or trying to find a working Bijou motor with a 12-leaved pinion. My friend who owns the clock would probably be happy with a quartz movement, but personally I’d prefer to keep the clock original if I can. Attached are some pics of the sorry mess. Any advice from one of the Smiths electric clock experts would be welcome! Phil
__________________
Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 5th Nov 2018 at 11:33 pm. Reason: Typo |
6th Nov 2018, 4:09 pm | #2 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
|
Re: Smiths ‘Bijou’ synchronous clock motor
Is there a reason why you can't just transfer the armature with the 12-leaf pinion into the good stator coil?
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments. |
6th Nov 2018, 5:36 pm | #3 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
|
Re: Smiths ‘Bijou’ synchronous clock motor
I’d thought of that, but wasn’t sure that they’d be completely interchangeable. The rotor shaft has to be driven out through the hairspring collet. I don’t want to cause any more damage, although I could practice removing the rotor from the duff motor to start with.
I’m keeping an eye out for a donor clock of the same type. Incidentally, there’s an excellent exploded diagram and plenty of descriptive information on these motors in T R Robinson’s ‘Modern Clocks’ but it doesn’t mention the different pinions.
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
6th Nov 2018, 6:36 pm | #4 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
|
Re: Smiths ‘Bijou’ synchronous clock motor
One has just been secured at a reasonable price. I’ll keep you posted!
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
10th Nov 2018, 2:02 am | #5 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
|
Re: Smiths ‘Bijou’ synchronous clock motor
Result! The donor clock had been bodged before, but the motor was a good ’un and measures well over 10 Megohms insulation resistance.
Phil
__________________
Phil Optimist [n]: One who is not in possession of the full facts Last edited by Phil G4SPZ; 10th Nov 2018 at 2:04 am. Reason: Picture added |
10th Nov 2018, 12:16 pm | #6 |
Nonode
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,820
|
Re: Smiths ‘Bijou’ synchronous clock motor
I’ve just got myself a clock like that! Mine has the marbled case rather than brown. It worked well, but the wiring was horrific and it had been ‘oiled’ with WD40 all over it... it looks like it was never designed to come apart after it had been assembled, so cleaning it is going to be fun! The motor is good in mine too
Regards Lloyd |
10th Nov 2018, 2:54 pm | #7 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
|
Re: Smiths ‘Bijou’ synchronous clock motor
It might be worth trying to wash the excess oil away from the movement, perhaps using a solvent like petrol or lighter fluid on a modellers’ paintbrush. Once thoroughly dry, try sparingly lubricating with light oil like 3-in-1. These movements have only two arbors and these are slow moving. Where the oil is needed is along the common shafts where several wheels and pinions run. Getting oil into there might be tricky, as there is very little end shake or gaps. A hypodermic would be ideal if you can find one. Normally no oil is needed on the teeth, other than on the first fibre gearwheel that meshes with the motor pinion.
If you do decide that complete dismantling is necessary, T R Robinson’s book ‘Modern Clocks’ contains a page and a half of very detailed instructions and I could scan it and e-mail it to you if you drop me a PM. But it requires some specialist tools and is not for the faint-hearted!
__________________
Phil Optimist [n]: One who is not in possession of the full facts |
10th Nov 2018, 2:57 pm | #8 | |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,866
|
Re: Smiths ‘Bijou’ synchronous clock motor
Well done, Phil.
There are countless variations and improvements of the Bijou to be found over its 20-odd year production run, meaning that interchangeability of parts is not as easy as it might seem. Quote:
Some early cheapies, particularly American-derived ones, seemed to be riveted together, but most of the pre-1960 Smiths stuff is eas easy to work on as any other clock. Could you post some pics in a new thread, please? Nick. |
|
10th Nov 2018, 5:16 pm | #9 |
Dekatron
Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,748
|
Re: Smiths ‘Bijou’ synchronous clock motor
Thanks, Nick.
I confess I much prefer the Ferranti movement to the Smiths, although in fairness to both manufacturers, their clocks survive in healthy numbers eighty years on, so we can hardly complain about the occasional duff motor!
__________________
Phil Optimist [n]: One who is not in possession of the full facts |