Gents GENTS C7 master / transmitter tips & info

[bruce linde]

just got this... it came with a 'gents of leicester controlled electric clock system' .pdf pieced together off of the message board.

i'd like to know how to get it running... what should i know? what do i need?

i did find this post, as well: Gents C7 - adding a C69 Bell controller

 

[bruce linde]

here's essential documentation:

[pdf]511757[/pdf]

 

[bruce linde]

for some reason i thought this was going to be difficult, but it couldn't have been easier.

i tried the 6v power supply i had purchased from kensclockclinic for my stromberg master clock but it did not stir the slumbering beast. i found a 12v power supply in the garage and hooked it up: we had lift-off!

i reached out to tinker dwight, who walked me through ohm's law to figure out how to set the variable resistor on the left.

amperes times resistance is equal to the voltage... I * R = E
which can be moved around to resistance equals voltage/amperes... R = E / I
desired amperes for the clock is .22, so 12v / .22 = 54.5 ohms​

i put a wire between the two power terminals and used my fluke voltmeter to dial in 55 ohms across the contacts using the sliding resistor on the left.

i then cleaned the contacts, escape wheel surfaces and other parts that interact when running, and it's been running ever since:

main -

secondary -

p.s.: love that they call it a 'transmitter' instead of a master clock:



p.p.s.: the pendulum assembly weighs in at 11 lbs

 

[bruce linde]

also found this really good installation/maintenance/repair guide... hope it helps someone.

a 4-page .pdf with enlarged versions of the annotated drawings in the document added 2/2/19.

[pdf]512043[/pdf]

[pdf]516108[/pdf]

 

[bruce linde]

excellent reading on gents (and other electric clock manufacturers):

Gents Pulsynetic Master Clock Intro

 

[bruce linde]

more docs:

- a gent catalog from 1925
- a gent brochure from march 1905
- a gent instruction manual from 1970

[pdf]512893[/pdf] [pdf]512895[/pdf] [pdf]512896[/pdf]

 

[bruce linde]

there was a Gents Master Clock Survey being circulated by the electric horology sub-group of the AHS (antiquarian horological society) in london. please see this thread for the .pdf survey: Gents - Gents Master Clock Survey

 

[bruce linde]

an early brochure... note the promised accuracy with the optional upgrade invar pendulum...

 

[harold]

I am about to trade for one of these. Can you show me where to hook up to the power points.

 

[bruce linde]

if the one you're getting is like mine, refer to the last photo in my post #3 above... it shows the hookup terminals and the variable resistor.

the resistance should be about 55 ohms for a 12V supply. connect the two terminals with a temporary wire across the the cabinet... do not have the supply connected for this measurement. measure across the open points (follow the left arrow from the 'clean me!' legend... with you meter set on ohms. the 100 ohm variable resistor ( lower left ) might have a set screw that holds it in place.

ohms law says I * R = E (also written as A * R = V (ampere * resistance = volta ('ampere' and 'volta' being the scientists who worked this out))). amperage times resistance is equal to the voltage. with a 12v power source and a target of 0.22 amperes (specified in the pul-syn-etic docs and the label inside the clocks) you can move the equation around to R / E = I or R = E / I or 12/0.22 = 54.5454... or close enough 55 ohms.

i have a slave/secondary clock winging its way to me and will have to re-do the math for mine when it arrives and i hook it up.

(thanks and acknowledgement to tinker dwight for walking me through this...)

 

[bruce linde]

some pictures from a 1905 Gents catalogue: water-level indicators

 

[Frank the Clock]

Bruce,
I don't know if you know this already but the date of manufacture was written on the label inside the top left. Often the labels get damaged though.

 

[bruce linde]

yeah... my label was damaged.

i received the following info from the electric horology guys in england:

"Everything in the picture ties in with the case number and a date in early 1948. It looks like a mahogany case, found in some 1947 clocks. The Agba case was introduced in 1948, but certain clocks had cases in other woods. Your example is one of the last to have 2BA terminals for the transmitter connections. These were superseded by a ‘Grelco’ Bakelite terminal block in that year. All looks in good order, including the contacts. At that date these were in a gold/silver alloy, and seem to be everlasting. if the numbers are as stated, the pendulum is not original. This is not uncommon. 8781 corresponds with a date in 1953, about September of that year."