Wiring a "Star Delta" machine

[Karl]

Hope somebody can help out - is it crucial for the phases to be kept in-line on a machine with a star delta start (ie l1 to l1, l2 to l2 and l3 to l3)?

Cheers

Karl

 

[Bright-Spark]

Karl

Not sure exactly what you mean, but for a three phase motor swapping 2 phases around will simply change the rotation.

You can connect the star contactor in any order as this is just connecting the ends of the winding together.

The connections on the main and delta contractors should be the same, on the incoming side or things are going to get very confusing.

Image snipped from google docs should make things a little clearer.

I hope this is of some assistance.

Bright-Spark

 

[Karl]

Thanks Bright Spark.

I'm probably barking up the wrong tree. Just wired up my 2nd hand panel saw which has star delta. First time i've used one. Normally all three lives can be connected to any terminal on the plug, if it's spinning backwards, switch 2 over. Fine. But i've wired this machine up, and nothing. There is power going to it, the digital speed readout lights up, and the brake/emergency stop buttons work fine. But switch on the star/delta switch, and nothing.

Cheers

Karl

 

[RobinBHM]

Thanks Bright Spark.

I'm probably barking up the wrong tree. Just wired up my 2nd hand panel saw which has star delta. First time i've used one. Normally all three lives can be connected to any terminal on the plug, if it's spinning backwards, switch 2 over. Fine. But i've wired this machine up, and nothing. There is power going to it, the digital speed readout lights up, and the brake/emergency stop buttons work fine. But switch on the star/delta switch, and nothing.

Cheers

Karl

Have you checked for any safety micro switches on the machine, or dodgy stop button not retracting properly. Sometimes relays click out need resetting, so may be worth checking those too. (Of course I have to recommend only qualified electricans should be poking around inside a machine....., if machine is not isolated there is risk of a shock and pushing in the motor relay/s will bypass the switch and could start the motor running)

It sounds like you have power going in fine, but most modern machines have a few safety featudes that prevent the motors starting up.

 

[Karl]

Thanks for the input Robin.

Both emergency stops seem to be working fine (retract then the "click" of the brake when pushed in). I had thought about the micro switches (I think there are 3), so i'll have a look at those tomorrow.

Cheers

Karl

 

[Karl]

I checked the micro switches, and they aren't the issue. Stop buttons work fine too.

I'm suspecting it might be the star delta switch itself. It feels rather "clunky" to turn. But I have no idea how to test it, so guess i'll have to find somebody local to take a look at it as i'm at the limit of my limited knowledge.

Cheers

Karl