Phase convertor & Blower - last question I promise :-)

[dubliner]

OK I'm going to post some pics of what I have, and my question is about the "starter" in the cabinet(pic 3). The 3 phase hook up is still intact so thats pretty obvious what I have to do, but there are 3 light gauge wires coming out of it to a magnetic on/off I guess? If thats so what do I need to buy and what does the big block in the cabinet do?. The RPC has its own cab & switch on the side(pic 1), so thats also straightforward. If I'm just going to hook up the blower for now, do I have all I need, except for the connection to my single phase panel & appropriate breaker? TIA Neville

[harold_weber]

I can't follow the wiring in your photo number 3 because its not focused very well. Some motor starters use "low voltage" starter relay coils - typically 24 volts. If this were the case for you there should be a 24volt transformer (and the relay coil on the motor starter would be labeled as needing 24 volts).

Possibly, you have a "line voltage" starter relay coil, and if so, you won't need a transformer and the first wiring diagram in this reference should help:

http://wiki.owwm.com/Motor%20Starter%20Wiring%20Diagrams.ashx

If that's what you have, then the three light gage wires are most likely to wire two momentary contact push buttons - one to start the machine and one to stop it.

Read the portion of the reference in red - - if you are not sure what needs to be done its a lot less expensive to hire an industrial electrician who will be sure.

[curtiss]

Looks like a pretty heavy duty setup you have there.

Do you have one of those things you wear around your neck where you can say "I'm stuck to the table and I can't get up !! :)

[dubliner]

Kind of, I'm Beta Testing one for Robert Ball.

[dubliner]

Posted some new pics in the previous entry.

[Gary Campbell]

Nev...
Those wires look like they are coming from an auxilary set of contacts. I think I saw term #'s & NO and NC. If so, remove them, they are redundant to your use. That is untill you want something else to come on with the blower.

[curtiss]

Posted some new pics in the previous entry.


Is that a "steel toed flip flop" I see in the photo you posted ??

Where do you get those ? They look great for electrical work.

[dubliner]

Very observant :-), I was only there to take a pic, I promise. The ARE insulated though.

[harold_weber]

I disagree with Gary. The Auxillary Contacts are used in most installations to provide a SAFETY feature. Scroll down to the first schematic in the reference I gave. The auxillary contacts are used to provide power to the relay coil after you release the Start Button. This method of wiring is used to make sure the device stays off if the power is interrupted.

[Gary Campbell]

In the case Harold mentioned, I now agree with him. In actuality I told Neville to have an electrician look at it in person. Without seeing it in person, its hard to tell.

[bcondon]

http://samplecode.rockwellautomation.com/idc/groups/literature/documents/wd/800-wd001_-en-p.pdf
Page 6


The concept is straighforward. If you do not understand it after the comment,
then have an electrican wire it up.

This is the CONTROL circuit of the contactor.

The Aux Contact are connected to the same closing mechanism as the
3 main phase lugs (the power to your blower). When the relay closes,
it closes the 3 main lugs AND the aux contact.

Why is this necesssary: The START button is only a momentary contact. When you push the START button, it closes the circuit. When you release the start button, it opens the circuit. SO what is happening is when you push the START button, the relay is closed and so is the AUX CONTACT which is in parellel with the start button. When you release the start button, the power now goes through the AUX contact instead of the Start button... and it will run forever....

Now, when you hit the STOP button (which is wired in SERIES with the whole circuit, the power is removed, the relay releases and the AUX contact is now open. When you release the STOP button, the circuit is perminently broken because the Aux contacts are open and the START switch is open.

Any other "emergency" buttons are wired in series with the STOP button (or shall we say that an emergency switch is just another STOP button in series)

Harold used the term SAFETY for this type of circuit, This circuit does have SAFETY in mind because if you have some sort of power outage, the power is removed and the relay is release just like hitting the stop button, the relay circuit is openned, the AUX contact is open as is the start switch. When the power comes back on, the machine will stay shut down.

If you had just used a switch for the machine, when the power came back on, so would the machine which would be unexepected for the poor operator.

===

Any industrial electrician has wired hundreds of these circuits so if this is still confusing, hire an electrician for your safety!

[dubliner]

Thanks all for you input, advice & cautions. I'm clear on it now so I appreciate you all taking the time to help - Neville