star delta

[mikehopkins]

Hello folks

I have been asked to wire a star delta motor auger feeder ,it is in a farm yard and the customer has asked for it to be wired via a waterproof plug and socket , so that it can be put out of the way during winter,etc.has any one a steer on how people get around the issues of doing such a motor on a plug.
any ideas much appreciated

 

[Plonker 3]

Sounds like you will need to mount the starter on the side of the machine after the plug and socket.

 

[telectrix]

can't see any reason why you can't use a 3 phase commando plug/socket. this can be enclosed in a semi enclosed IP rated housing.

 

[johnboy6083]

you should really use an interlocked socket that has an isolator. This way the motor cannot be disconnected under load. Try mennekes.

 

[hermetic]

If you mount a star/delta starter (or any other kind for that matter) on an auger it will shake it to bits in no time flat. Why not wall mount the starter near the supply and use a four pin and a five pin sockets to connect the auger, with suitable signage like "AUGER ONLY" on it.

 

[ian.settle1]

If you mount a star/delta starter (or any other kind for that matter) on an auger it will shake it to bits in no time flat. Why not wall mount the starter near the supply and use a four pin and a five pin sockets to connect the auger, with suitable signage like "AUGER ONLY" on it.

And how pray can he connect up the motor as both ends off the coils need to go to the starter using 4 or 5 pin plug ?

 

[Knobhead]

Don't they make 7 pin plugs then?

Nice idea hermetic, but not practical.

 

[Rockingit]

We use a similar concept in rock and roll rigging for truss motors..... you have a 3pin delta socket for the mains to the motor, and then a separate 4pin socket to send the starter/activation/ph rotation. In rigging it works well as it means you can have a string of 3ph motors fed from one point, and the control gets operated via contactors in one single box, so with one 'on/off' button (we call them 'pickles') you can control any number of motors to run in up or down combinations.

 

[Knobhead]

The problem I can see with that is the lack of interlocking between the sockets and starter. The last thing that you would want is someone plugging in to the delta socket without the star being connected and pressing the start button, you would have a plug with 400V on it’s pins.
In you’re situation Rock you would (hopefully) have people that knew what they were doing. We’re dealing with Farmer Brown.

 

[hermetic]

And how pray can he connect up the motor as both ends off the coils need to go to the starter using 4 or 5 pin plug ?

3 coils = 6 wires. I suggested a four pin AND a five pin so that they cannot be cross connected!

 

[ian.settle1]

3 coils = 6 wires. I suggested a four pin AND a five pin so that they cannot be cross connected!

See Tonys comment abovr about Farmer brown.

 

[hermetic]

I read it, usually even farmer brown can be relied on to plug things in, but I take his point. In a situation like this you could use an interlock to hold off the starter coil till both sockets were in, it is not impossible, you sometimes have to be a bit inventive, but mounting a starter on a vibrating machine is definitely not a good idea.

 

[Knobhead]

Farmers around your way must be special, must I’ve come across would even manage to get a 5 pin plug in to a 4 pin socket!

There is a way around it but it’s not cheap.

 

[VoltzElectrical]

i'm sure I'm not the only one who doesn't really 'get' what's going on here. I'll put my hands up, I don't know much about motors or control, but would love to learn and this seems a great opportunity to learn something. so if anyone (Tony??) can please post a definitive guide to the problem and solution ( by PM if necessary) then I would be extremely grateful.

thanks

 

[Knobhead]

i'm sure I'm not the only one who doesn't really 'get' what's going on here. I'll put my hands up, I don't know much about motors or control, but would love to learn and this seems a great opportunity to learn something. so if anyone (Tony??) can please post a definitive guide to the problem and solution ( by PM if necessary) then I would be extremely grateful.

thanks

Look at http://www.electriciansforums.net/commercial-industrial-electrical/43777-motors.html in the industrial section

 

[Knobhead]

If you use sockets with an interlocked isolator the danger of live pins can be removed. See drawings

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