Lostazhell (Randy)

Randy,
Is that wire heading to the recept blue or green?.
I hope that that wire with the tape on it isn't hot?.

Based on the wire count and color code, I'll bet there was one of the old Simplex clocks there. It used several wires and was syncronized to a central clock. Those who remember the clock in thier school "jumping backwards" know what I'm referring to.

The decal in the backpan may tell the story...

Mike, the only wire showing voltage was the one going to the receptacle, (which is blue)

MX has it right, this used to be where a Simplex style(the label in the can actually said Dukane)clock was.... there was just a regular clock hung over the opening though, plugged into that taped up outlet.

MY college Syracuse Univ had a system like this in their engineering building. Problem was that students kept stealing the expensive clocks (which would operate on ordinary 120VAC I heard) so maintenance just bought and used ordinary Telechron wall clocks plugged into the 120VAC feed. Using those outlets that would be used for snap fits into square holes in bathroom light fixtures (avoided exposed screws).

when you email a picture to a moderator, do you leave the topic title to the moderator? If so, you're in clever hands with electure .

The problem with running the slave unit of those Simplex clock systems by itself; is that unless you have the master clock, you can't really set the time on the thing by itself.

At least one of the ones I saw in my old school (some professor had it hanging on a nail on the wall in his office and connected to a 110 volt socket via a chopped off piece of extension cord) didn't have a time-set knob on it.

The prof said he had to wait until it was about the right time that was showing on the clock and then he'd plug it in.

So...unless the students at Syracuse knew how to trigger the setting mechanism on these clocks, I wonder if they were probably stealing them just out of mischief?

EDIT: Couldn't whoever did this knockup of a job have just used a replacement female cord connector? Just as non-code but at least it would have been a bit...safer than an exposed in-wall receptacle.

[This message has been edited by SvenNYC (edited 10-19-2005).]

There wasn't a beat-up DeLorean parked outside the bank, with a garbage pail in the trunk, by any chance?

Alan

Thanks, but that one was Randy's

Well, I think it was considerate of them to leave spare wire nuts in box.

I actually have one of those Simplex school clocks; it had a clutch/solenoid mechanism which was operated via the master clock (don't remember how on that particular one). I took the 'slave' innards out and, yes, it CAN be easier to wait for the proper time to plug the clock in rather than removing the spring for the glass 'cause getting that spring to cooperate is a REAL PAIN!!!

I've also seen an IBM school clock circa 1953 or so that had a small vacuum-tube receiver which apparently listened for a 1 KHz tone on the power feed. The clutch would engage when the tone was detected.

Just my two cents' worth...

Hi, I'm aware of European systems who run the seconds of a 'slave dial' on 220 Volts 50Hz, the seconds hand makes one full revolution in about 59 seconds and then stops till the Masterclock provides the 1 minute pulse @ 24 Volts DC, which releases the brake and the process starts all over again. This will keep the seconds hand in step with the master clock.
Minute pulses are positive , negative, pos. etc to prevent a clock jumping 2 minutes in case of contact bounce from the master.
In the drive from the synchronous motor to the seconds hand is a slip clutch provided which avoids stalling the motor.

Many railwaystations in The Netherlands and Germany use these types of clocks ( T&N and FAVAG ) The seconds hand makes a smooth pulsing movement and stops briefly at each second. "schleichenden sekunden".

In the Simplex system I think that a similar approch is used mains voltage for the motor and 24 Vdc for the minutes although not with changing polarity.