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Strange Equipment Found

Strange Equipment Found

Strange Equipment Found


Does anyone knows what is the thing below?
I found it in an old MCC included in motor control circuits and i have no idea what it is and what is doing.

RE: Strange Equipment Found

It looks like an octupus, but good post. I hope someone can help you here!

RE: Strange Equipment Found

Could it be similar to a mechanical timer? Motor is for some process machine, like filling a tank, when 'X' gallons have been passed through it shuts off the pump?

The white pieces look like interchangeable cogs that determine when a specific function happens with regard to the entire 100%-finished process.

Dan - Owner

RE: Strange Equipment Found

It's a cam controlled sequence controller.
Generally used to control a sequence of operations.
Normally driven by a clock motor. I have seen models driven by the controlled machinery.
Some models were advanced from step to step by a solenoid and ratchet arrangement.
The advance from one step to the next may be timed or it may be controlled by an external event.
One familiar operation that was controlled by similar devices in years past would be a washing machine.
Step one: Fill, Timer motor off, When the level switch is true the timer will advance to the next step.
Step two: Fast wash, Controlled by timer.
Step three: Slow wash, Controlled by timer.
Step four: Drain, Controlled by timer.
Step five: Fill, controlled by level switch.
Some models such as washer controllers have fixed steps.
Some models are universal in that the position and duration of each cam may be adjusted.
Similar timers were used to control traffic signal lights.

"Why not the best?"
Jimmy Carter

RE: Strange Equipment Found

Waross, thank you very much for your explantion.
This one was used to control mixers in tanks with high viscosity product and from your explanation i think i will be able to understand exactly what this sequence controller was doing.

Once again thank you.

RE: Strange Equipment Found


cam controlled sequence controller

Commonly referred to as a "drum controller" or "drum timer" because of the cylindrical shape of it.

Now days this would typically be replaced with a PLC. (Which often include 'drum timers' in their native language.)

Keith Cress
kcress - http://www.flaminsystems.com

RE: Strange Equipment Found

Ahhhh... memories.

For decades, one of the first tasks assigned in almost every beginner PLC programming classes was to create a PLC equivalent of a "drum switch" just like this. The problem eventually became that nobody taking the class had any idea what a rotating drum switch even was!

"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

RE: Strange Equipment Found

waross described it perfectly.

I've serviced blow molding machines that were sequence controlled by type of device.
They were actually quite complex, having 20 - 30 switches, having multiple other control devices integrated into the control.
Those machines drum controllers were sequenced with a solenoid and ratchet... a dead simple and rock hard reliable electro mechanical gizmo.
At each stage they cause a function to occur until its completion, whether that is based on an actuator meeting a limit switch, or pressure switch, or light sensor, or if it was a timer. When that condition was met it would index to the next step.
Super reliable. These things were a decade older than me when I worked on them, and the drum timer was not the problematic part.

RE: Strange Equipment Found

Drum controller were used reliably for years to control traffic signal lights.
A common configuration was two drums.
The first drum was driven by a timing motor. This supplied the output pulses to advance the second drum. The second drum was advanced by a solenoid and ratchet mechanism. The second drum switched the various lights.
There were replacement gear sets for the drive motor so different cycle times for a complete cycle could be implemented.
There were also check circuit that could skip a pulse or add a pulse if the second drum got out of step.

"Why not the best?"
Jimmy Carter

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