Motor control for chicken house

[buzzlightyear]

what happens when the door gets stuck open and the chicken fly the coupe.

 

[grumpyjohn01]

what happens when the door gets stuck open and the chicken fly the coupe.

My mate Chicken Tim sees it on CCTV, jumps in his truck and Mr Fox goes down in a hail of buckshot...not very Disney is it...!

 

[grumpyjohn01]

I can't see any interlocks or safety device either. Did you get this resolved?

Hi there, Thanks for your response, I probably posted before I thought enough about this! I derived my drawing from a standard reversing contactor diagram and the info that came with the motor/gearbox. Are you familiar with this sort of stuff? Am I on the right lines? The interlock mentioned seems to me to be achieved with my last drawing (003) but I am seeing reversing contactors online with mechanical interlocks, does this do away with the need for this? What sort of additional safety devices are we talking about here? Oh & btw I have added a stop in series between the overload NC contacts and the emergency limit switches. Thanks John.

 

[davesparks]

Ok here is another go, I rectified at least one mistake. The coil of the open contactor is energised via NC aux contacts of closed contactor and vice-versa, is this not interlocking?
The doors themselves are lightweight plywood being winched up or lowered down under gravity, I doubt they could even bruise a chicken. Is the 'safety device' being mentioned to stop the doors causing injury?

A reversing starter normally has electrical and mechanical interlocking for redundancy.

Is something getting crushed by the door the only possible way this could cause injury? Is it impossible for something to get caught in the tracks the door runs in or crushed by the top of the door as it is raised?
What about the motor, gearbox and whatever mechanism connects them to the door, is it possible for something to get caught in there?
Will anyone need to do any maintainence or setting of limits with the system energised?

Machinery is not my area, but these things seem like obvious possible dangers to me.

 

[Bobster]

Reversing contactors require both a mechanical and electrical interlock.

They are quite often sold together.

This was discussed in a thread before, an I posted relevant regulations to match. I can't find it to quote right now though.

 

[SheffSimon]

The law (Supply of Machinery Regulations) says that the first thing you must do is a risk assessment. By "you" I mean your customer and/or you.

That would be before worrying about whether you need to interlock your reversing contactor.

The risks to both operator and maintainer may be negligible, but you need to document them.

Davesparks above has already made a good start.

 

[Automation ATO]

According to the power of the motor. Choose a suitable controller for the current size

 

[Darkwood]

If I can interject and to add weight to others concerns here, it only take a little knowledge to make a functional system but that does not mean it complies to the relative standards.

In the design stage thought must go foremost to safety following a risk assessment, this may include extra measures like redundancy eg fail safe design and complying to the relevant directives etc, it is evident with your replies and posted schematics that you are inexperienced and lack knowledge in this field, the forum will not provide a step by step guide for you either so it is my recommendation that you work alongside someone competent in this field or pass it fully onto them, we would definately advice you do not attempt this project given you are attempting to draft up a very basic functional schematic that would not comply even if it worked in principle.

I am happy to leave the thread open to field some more questions on the matter which may help you realise the depth of adequate design needed and the responsibility that lays solely on your shoulders in undertaking this project.