Timers

[Brad93]

I have a few customers now with machines from the 90s that used mechanical timers.
They have failed, used to be able to send them to a company up north, now they've been taken over by sulzer and they no longer repair them.


Basic operation of the machine is such:
Two speed three phase motor.

Set first timer to say 3 minutes, motor runs at slow speed, after 3 minutes the machine switches over to high speed, where a second timer runs for 12 minutes, after which the machine stops.

Now i've found these Finder timers which are well within budget.

https://docs.rs-online.com/6271/0900766b816d52c9.pdf

But i have no idea what ones i would need.

Anyone with experience in such matters?

 

[Onoff]

Two speed three phase motor.

Double star wound?

 

[Seadog]

Not speaking from a position of specific knowledge, but isn't the timer just controlling a set of contactors that power the motors?

 

[daleyd]

What are the existing timers that are fitted? Get a spec from these and go from there if you can.

From the description it sounds like you need an on delay function - so the start is energised and the 3 min timer starts - after 3 mins the on delay runs out and will energise a second on delay timer for 12 mins, after this it resets. But it’s not a given that’s how the circuit is working.

they could equally use an off delay (where a timer counts down from the first timer running out) to trigger the second timer, hence it would pay to look at the existing functions.

 

[Agroshield]

Can you draw a fag packet diagram of what the input and output of the timer needs to look like.

Clearly, when it is off, there is no output from the timer at all. When it is in the first three minutes, I guess one output of the timer is active?

At the speed chage time, what happens there? Does the initial output go low and a different one go high? Does that first output remain high and the second one also become high (and then at switch off time, both go low)?

In your post, those two words "switches over" need some expansion to describe the exact logic of what that requires from the timer.

What supply voltage does the timer run on? What is the control voltage the timer is managing?

 

[daleyd]

There’s a description of various timer functions here

https://media.crouzet.com/catalog/_notice/pdf/CO_TM_00_Timers_function_diagram.pdf

 

[Brad93]

I haven't got a wiring diagram for either machine, they're too old.

The machine currently employs two timers.

Said machine.

 

[Onoff]

Sounds simples! Something like this to fire the existing contactor(s):

 

[daleyd]

I haven't got a wiring diagram for either machine, they're too old.

The machine currently employs two timers.

Said machine.

View attachment 481535

Can you get any details off the existing timers, eg part numbers and any settings (switches etc). You can hopefully cross reference these to get your new ones to the same spec,

 

[daleyd]

The age of them they are unlikely (but not impossible) to be multifunction (where you can choose what type of timing to use)so hopefully if you can get part number off them it will tell you exactly what type of timer they are.

 

[Brad93]

Sounds simples! Something like this to fire the existing contactor(s):

View attachment 481536

No good to me. Needs to be adjustable on the panel of the machine as per attached photo.

 

[gaz1]

i think you might be after something like these

Electro-Mechanical Timers | Eagle Signal

Eagle Signal are the market leaders in rugged, accurate & reliable electro-mechanical timers, leading industry standards for several decades. Our range of On Delay, Off Delay, & Reoeat Cycle Timers will have the functionality to meet whatever your application requires.

www.specialtyproducttechnologies.com

 

[Brad93]

i think you might be after something like these

Electro-Mechanical Timers | Eagle Signal

Eagle Signal are the market leaders in rugged, accurate & reliable electro-mechanical timers, leading industry standards for several decades. Our range of On Delay, Off Delay, & Reoeat Cycle Timers will have the functionality to meet whatever your application requires.

www.specialtyproducttechnologies.com

$700 dollars each Gaz.
Probably not a go-er

 

[Brad93]

Nearest modern equivalent mixer i can find

 

[ajlelectronics]

No good to me. Needs to be adjustable on the panel of the machine as per attached photo.

Do the timers control the motor windings directly or do they feed contactors to do the "heavy lifting"?

 

[daleyd]

Do the timers control the motor windings directly or do they feed contactors to do the "heavy lifting"?

Those timers definitely won’t be connected to motors directly.

 

[gaz1]

there is electonic timer s

1-10min timers

https://www.electroschematics.com/adjustable-timer-1-10-minute/

timer with relay control

Adjustable Timer Circuit Diagram with Relay Output

3 Simple ways to build an adjustable timer circuit diagram (1 to 10 minute timer, cyclic on-off timer and Arduino timer to adjust long intervals of time).

www.electronicshub.org

look for astable mode as can be used in your application of timed on and timed off

 

[daleyd]

Nearest modern equivalent mixer i can find

View attachment 481542 View attachment 481543 View attachment 481544

I’m not sure that really helps, you really need to find what the existing ones are. You could take a stab with the same type on that but your circuit might be different.

 

[ajlelectronics]

Those timers definitely won’t be connected to motors directly.

As I suspected. So a fairly straight forward job of a pair of sequential timers then. What is the output voltage of the existing timers?

 

[Brad93]

This is the timer fitted to
modern mixers.