on/off and emergency stop circuit using relays

[mabauti]

e stop circuit

I need a simple electric circuit using relays and a push button for turning on/off the power supply and an emergency stop for disabling the power supply.

ideas are welcomed

 

[KMoffett]

mabauti,

We need more details!

What's the power supply's input and output voltage and current? Do you want to do all three functions with one pushbutton? What's the load on the power supply? And...any other details you can add.

Ken

 

[FvM]

You can use the circuit used in any simple machine involving a contactor. It uses a N.O. start and a N.C. stop button and a N.O. holding auxilary contact at the contactor. Emergency stop is simply by additional series connected N.C. contacts.

I'm confident that you are able to imagine the circuit without a schematic provided.

 

[mabauti]

just ONE push-button for off/onn and the emergency buttton

 

[FANT]

Be careful about the emergency stop that in Europe with the EN60204-1 and the machine ry directive all the emergency units must be certified by a third body.
If the circuit is for educational purposes OK, if it is to be installed ina amachine take a lot of care.

Mandi

 

[FvM]

Not certfied generally, as far as I know, the EU machine directive at least is based on manufacturer (self) declaration. But this would be a different topic.

Having an on/off pushbutton clearly contradicts established safety philosophy and also any requirement of intuitive operation to my opinion. It may be useful for light switches but can be problematic even in such simple cases.

Imagine a number of on/off pushbutton light switches at a wall. You want to switch out the last light but are not sure about the right one. Usually you're switching any other circuit until you found it. Sounds funny, but may be expensive for a company in terms of lamp lifetime.

 

[cyberrat]

Perhaps a bit of googling is called for.

I.E. try looking here for info.

 

[mabauti]

Thank you cyberrat.

I clicked the (helped me) button

 

[FANT]

To FVM:
Alla the Emergency devices follow the annex IV of the machinery directive and then cannot be certified by the company that produces it but must be a third party company.

Mandi

 

[FvM]

the Emergency devices follow the annex IV of the machinery directive and then cannot be certified by the company that produces it but must be a third party company

No, not generally. Machinery directive 98/37/EC Annex IV is a limited enumeration of machinery types. Some types of safety equipment are covered by the list, e. g. safety light barriers, but not the Emergency devices, e. g. a simple emergency stop button.

Furthermore, an external certification is required generally for Annex IV machinery not underlying a harmonized EC machinery standard. If a harmonized standard exists (there are a lot), the manufacturer has an option for external certification. Alternatively he can deposit the documentation.

 

[gringo.ramiro]

Can u pls explain this ckt..

 

[chuckey]

For a start Drive1 and drive 2 must be on ( contacts closed). Pushing the on button feeds the +24V down to the 4 contactors( K10t, K20t, K30t and K40) so they all pull in and contact K40 is made and keeps the +24V feed going when the ON button is released. When any of the "safety circuit" contacts are broken, the +24V feed is broken and K10,20,30,40 fall out and the circuits are broken.
Frank