Electric clocks with power backup

TYPE I

Designed to address unstable A/C frequency or long term power outages or DC Mains power - or any combination of this.

Their timekeeping is based upon traditional mechanical clocks- balance or pendulums

TYPE II

Designed to address short term power outages- the main timekeeping is accomplished by a synchronous motor with a mechanical emergency backup .

The backup is typically not a precision timekeeper. These clocks are limited to A/C operation only.

Based upon these types I have provided a initial list of manufactures of these clocks, the types they made and some general descriptions of each.

There is much to be learned here and any additions and or corrections would be appreciated.

My Email add is:

KKERR@Voyager.net

Mail:

Kenneth Kerr

531 East Main St

Eaton, Ohio 45320 .

Phone

937 4562310

Current list "RULES"

Only clocks designed to operate directly from "Mains" current are included.

Clocks that used mains current through a power supply (even if the power supply was original to the design- IE, not battery operated), are not included at this time.

When, and if included, I will; probably add another "type" to cover them.  

TYPE I

Herschede / Revere

clock types

Strike

market type

voltage

Balance / pendulum

Wind / drive system

(Herschede owned the Revere name)

Hall

Chime and hour

Home

110 V AC

Pendulum

Spring drive for the time- synchronous motor for strike and chime / various ways to wind.

typically used a "balancing spring force" method to sense when wound.

Shelf

Chime  and strike, hour strike only

Home

110 V AC

Pendulum

Same as above

Comments:

Herschede made these in many varieties - none quite the same- most varied of all of the manufactures of these clocks both in types and movements.

Imperial

clock types

Strike

market type

voltage

Balance / pendulum

Wind / drive system

Wall square case

Time only

Business

110V AC, DC and other voltages possible

Balance- 7 jewel platform

Spring drive wound by a heavy lever which stops winding when the lever no longer

can overcome the spring- contacts are at the bottom of the lever.

The lever is reset by two coils through the contacts

Wall - Banjo

Time and strike

Home

110V AC

Balance- 7 jewel platform

Spring drive for the time- wound by the strike motor when the clock strikes

Comments:

The motor has power all of time and is stopped by the strike mech.

The banjo is not common- there is evidence to indicate that Imperial replaced most of the Banjo's movements

with a two motor (one for time, one for strike) synchronous only movement 

International Time Recorder

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Wall- master clock

Time only

Business

110V AC Might have had other voltages or DC

Pendulum

Weight drive through a differential - rewound by a small GE motor controlled

by a Geneva gear driven switch

Comments:

Controller for slave clocks- the slave clocks did not run on 110 volts and required the system to have a power supply to run

Sangamo

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Shelf, wall, hall

Time only, time and hour strike

Home/ business

To order- examples include 110V AC, 25 V AC, 100 V DC

11 and 7 jewel platform

Spring drive through a differential (some time strike models only)

Wound by a constantly powered motor that is braked when the spring is wound

Master / secondary system (to date all are wall clocks)

Time only

Business

To order - same as above- note the master set the secondary time via the mains voltage- three wire system

Controllers had 11 jewel platforms - Secondary had 7 jewel platforms.

Same as above- all clocks  could run 24 hours on their own without power

the secondary were set to time by the primary once a hour

Comments:

Sangamo built a few Westminster strike hall clocks. Not enough is known about these by me to comment on them

Very early Sangamo time only movements do not have a brake- Sangamo selected main springs to balance the force of the wind motor.

Sangamo built two different Master / Secondary systems- neither the masters nor the secondary can be interchanged between the two.

All secondary will run on their own without a controller

South Bend Watch Company

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Shelf

Time only

Home

110V AC

Jeweled balance- number of jewels in not known

Spring- wind system is not known.

Comments:

Very rare - South Bend built a few working clocks as development examples but never went into production

The wind must have been very well designed as one model has been running continuously

since it was built- without service!

Seth Thomas

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Shelf

Time and time / hour strike

home

110V AC

Balance- time only /  Pendulum for time & hour strike

Spring drive via a small GE "eddy current" motor

This motor is stalled via a brake when the clock is wound up.

Comments:

I have only seen one complete clock and one movement.

Seth Thomas may have made some other types according to comments I have heard.

Tork clocks

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Unknown- existing example consists of a dial, hands and movement

Time only

?? Would guess it to be home

110V- listed for AC- could use DC?

2 jewel platform

Spring drive- wound through a oscillating bar / contact system.

A Geneva gear system on the spring barrel shuts of the wind

by stalling the oscillating bar resulting in keeping the contacts open.

Comments:

Called "windless" on the movement can. Movement itself was made in Germany. 

Winding system seems delicate and prone to failure. Flexible wires are connected to the contact assembly  

and these flex with each wind oscillation. The movement is connected to the AC through spring loaded fingers in the movement case / can.

Loose movement

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Brand unknown

Unknown, This movement would not power very large hands

Time only

Unknown, probably home

110V AC

no jewel pin pallet platform

Spring motor barrel drive. Motor wind is stopped through a complicated system of gears on the spring barrel

that move a hook into position to stall the motor thus stopping the rewind.

Very positive and exact in operation

Comments:

Expensive movement to build considering the cheap platform.

Would have fit into a very small case.

Type II

Note- all of these clocks are AC only since most of the time the AC provides the time keeping

Hammond

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Shelf, Wall

Time only

home, business

110V AC

flywheel / brake arrangement

Spring barrel- I have not studied the wind system in depth yet.

Comments:

These the title "Bicronous" on the dial. One of the most common of all of all power bridging clocks.

The motor is NOT self starting. The reserve system has to keep the motor spinning so that it will

start when the power comes back on. The system is complex, with clutches and the like.

These clocks had a calendar option for day of the week and day of the month.

Herschede

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

small to large shelf

Chime, strike, and time only

Home

110V AC

Balance- various from decent quality platforms to alarm clock type mech.

varies- from a inside out Geneva drive hook system to a spring force balance mech. 

Comments:

These movements seem to be almost unlimited in type and variety- from the most compact time only to large

Chime and strike. Some work very well, others seem to be poorly designed. None where cheap to build.

All used Telechron motors.

International time recorder

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Unknown- probably small wall case

Time only

business

110V AC

large alarm clock type balance

Spring drive- large reserve. Uses a telechron rotor to drive the clock

and wind the spring

Stanford

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Small shelf

Time only

Home

110V  AC

Unknown

Unknown

Comments:

I have not seen one of these- they were made on the West Coast and there may be more examples there then here in the Midwest.

Telechron / GE

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

(GE and Telechron marketed many Identicale clocks)

Shelf, Hall

Chime

Home

110V AC

Unknown

Unknown

Comments:

I have not seen many of the these. The advertisements refer to this as a "auxiliary movement" They were noted a  "A" in the model number

It only seems to have been listed for various chime models

Construction would seem toindicate the Herscede may have built some or all of these movements.

ERRATICA:

Loose movements that are still not totally identifiable or specialty "clocks" such as automatic power switches

International time recorder

Clock types

Strike

Market type

Voltage

Balance / pendulum

Wind / drive system

Unknown- probably small wall case

Time only

business

110V AC

large alarm clock type balance

Spring drive- large reserve. Uses a telechron rotor to drive the clock

and wind the spring

Comments:

Uses ITR switches and components but is not stamped as such. 

Very heavy built clock- partially incomplete so hard to say  how it worked