Switch 3-phase power with Uno?

Does anyone know if it’s possible to switch a 3-phase (400V) breaker from the 5vdc from the Arduino. Obviously it would have to go through a relay.

Has anyone done this before? And does anyone know what kind of relay/relays I would need

I will have it with a gsm shield. I want to be able to switch a 3 phase motor on and off remotely with my phone.

The correct way to start and stop a three phase motor is through the use of a manual or magnetic motor starter. A starter consists of a switching device (either a switch or relay device) connected to an overload relay. These have special devices in them known as overloads ("heaters") that will either mechanically or electrically trip the on/off device to protect the motor. If the motor is thermally protected, it will be marked on the name plate. If not, the use of a starter is required, otherwise you risk burning up the motor in an overload condition. The circuit breaker feeding the circuit most likely wont see the problem until its way too late, if even then.

So first figure out the specifics of your motor and then do your studies to find out the proper way to switch it.

You could use an inverter drive. That will enable you to run the motor from a normal 230 V supply and can be controlled by logic level inputs. It will also give you all the required safety and overload protection.

Russell.

if you have an existing motor, you will have one of the above.

if you have a manual contactor, you will need to swap that out for a magnetic, or go with the inverter.

inverters are designed to work with low voltage sginals,
but for the magnetic starter, you may need a relay they are typically 120VAC here in the states as the ‘low’ voltage option. DC coils in this equipment is hard to come by.

stuwilson: Does anyone know if it's possible to switch a 3-phase (400V) breaker from the 5vdc from the Arduino. Obviously it would have to go through a relay.

Has anyone done this before? And does anyone know what kind of relay/relays I would need

I will have it with a gsm shield. I want to be able to switch a 3 phase motor on and off remotely with my phone.

Contactors are available to switch 400V 3-phase but their coil is usually energised by 230Vac. So you would need a relay with 5Vdc coil and adequate contact rating to switch the 230V.

As you evidently have little knowledge of working with such components and the high voltages involved, I strongly recommend that you get a suitably qualified electrician or electrical engineer to do this for you. You need a qualified person experienced in working with 3-phase equipment in an industrial environment, not an electrician who only has experience of domestic installations.