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#SHARP ALARM CLOCK BROKEN SERIES#

#SHARP ALARM CLOCK BROKEN SERIES#

Note: Applies from 85x series and the clock motor is a 110v unit with a 12k resistor in the circuit. Leave running like this for a few minutes and smear a little light grease on the nylon worm. It should now be almost silent in operation.

The motor should self-start or may be assisted with a turn on the nylon worm gear. Return to horizontal position dangling on the leads. Turn the motor from horizontal to vertical and brush the end of the shaft so the fluid runs down inside. Now get a small artist’s brush and pick up a droplet of fluid. Get a can of WD40 or sewing machine oil and spray/pour a little in the lid. Undo these and withdraw the motor with the leads still attached to the unit. Remove the back and expose the clock motor.

If you can hear the clock, it needs attention. They are robust units but after many years in a warm atmoshere the bearings run dry and the motor can be heard whirring. 24 hours a day – for years without stopping. By definition the clock must work for the lifetime of the appliance. The clock is an Achilles heel of the vintage teasmade. There, that’s the nannies satisfied for now! Dealing with a noisy clock ( Doug Fennell) Our mains voltage of 240 can kill! If you are unsure about working on anything that uses the mains, better safe than sorry. Do not scrap D25s or motors with faults – there is not an endless supply, and everything is repairable.Don’t squirt WD40 in a clock apart from anything else, if anyone uses ammoniated clock cleaner, all the brass bits will turn a dirty green, and you will have to spend a week getting it all off!.Treat the field coil with respect – if you find a Teasmade in a damp shed, attic or garage, do not switch it on until it has been in a warm room for a week.Don’t lubricate parts that should be dry.

Don’t wash a clock in solvent without dismantling it – you just rearrange the muck.

Dos and Don’ts – read this even if you are in a hurry ( Mike Phelan) So, we have an accurate motor – all we need is some gearing to reduce the speed to once a minute, then once an hour, then once in twelve hours – all these to make the hands operate. Because there is a 50-50 chance it will spin the wrong way, there is an anti-reversing device in the clock (see below) that gives it an abrupt shove if it tries to reverse. How do we spin it? The rotor has pairs of poles that do not fit the field poles exactly, so if we turn on the current, it starts to vibrate until the inertia of the rotor makes it spin. If we spin it somehow, it will lock in to rotate (either direction!) at 50/15 revs per second – 3.33. Inside this is the bit that goes round – the rotor – this has a steel magnet formed as six pairs of alternate poles. If you look inside the motor (see later) you can see the annular polepieces have 15 interleaved projections – this gives alternate north and south poles rotating 100 times a second. The fine wire and thousands of turns mean that very little current is used. The clock motor in the D25 has two annular polepieces that surround a coil of fine wire that is connected to the mains this is called the field. It has no concept of timekeeping itself the accuracy is because the Grid supplies our power at a precise 50Hz – the mains voltage reverses itself 100 times a second.

The clock is simply an electric motor and gearbox. Arbors have pivots that run in pivot holesĪ quick résumé of how a synchronous electric clock works ( Mike Phelan).All the wheels geared together is a train. Clocks have wheels and pinions (old mangles and farm implements have cogs).