Terminal Board basics?

[Brian448]

I am new to the world of wiring things and I am in need of some education.

Note: I will add pictures to help clarify what I am dealing with asap as I know my descriptions will most likely not be very good. LOL

We (at work) are installing an air compressor. Instead of using the existing START/STOP switches we have also installed a wall box which will act as the START/STOP control for the compressor. It is a Sullair 40HP series 10B compressor. We moved the transformer from the compressor to the wall box and removed the wires from the hour meter and START and STOP switches on the compressor door.

Currently the wires from the other main components are still plugged into the terminal board as intended. This is where that question of needing some knowledge thrown my way comes in. How exactly does a terminal board function. I see all these wires plugged in from components along the right side of the terminal and I do not understand the logic of their placement.

As per the boss' instruction, I ran a white wire from the (moved) transformer (X2) to the left side of the terminal board also numbered "2". Running the wire from the transformer to the TB2 slot... does that give the whole terminal board power? How do you determine which side of the terminal board to use plug into? He did not explain to me why or how this is supposed to work and he is not around today for me to ask. That is why I am here pestering you guys with the noob questions. Ha! I am an aircraft mechanic by trade so am not mechanically ignorant but I have very little electrical experience to draw from on this kind of thing. If it is mechanical of hydraulic, I am your man, but this is a brain buster to me. So any help would be appreciated. I feel like once I can wrap my head around some of the basics that I am missing, then the pieces will start to fall into place. Thanks in advance.

And I will post pics shortly to help illustrate.

 

[Brian448]

Here are the pics of the compressor and wall box.

Notice that moving to the wall box we now have a start switch then a three position switch (HAND/OFF/AUTO).

The only component wiring that was removed is the Hour Meter. I am trying to figure out how that needs to be wired in to this new configuration as well.

 

[Brian448]

And for additional assistance, I am attaching the original wiring diagram of the compressor. Note that ours is a standard air cooled compressor so anything labeled in the schematic as "water" or "optional" is NOT installed on this unit.

 

[porcupine73]

Basically anything that is moved to your new control panel needs wires between it and where it was connected in the compressor control panel.

So for example, if you moved the control power transformer, it needs X1 and X2 connected to wherever they were in the original panel.

On TB's / terminal blocks, there is not always apparent logic in how it is layed out. Sometimes the panel builder just goes by the drawing or uses a method that does not seem apparent. Usually the equipment is wired to one side of the block, and then all control panel connections to the other side, just to keep it neat and provide an interface between the equipment and controls.

Note that ground shown on X2 off the transformer on the drawing. That is very important to make sure that is intact. Otherwise the voltage on the transformer secondary can float with respect to ground and can cause bad things to happen.

I see the control power transformer has some things wired in series with X1 which are safety features, such as a contact for the motor overload (OL's), and what looks like a phase monitor relay to shut it down in the event of loss of one of the power phases such as a blown fuse, probably to keep the motor from single phasing.

Just an additional note on this type of thing....sometimes it is risky to make engineering changes to equipment without the manufacturer's approval. Especially if that panel had say an overall UL label or something like that. There could be insurance implications in modifying it if something goes wrong later.

 

[Aceman]

I am new to the world of wiring things and I am in need of some education.

We (at work) are installing an air compressor.

I usually cut guys slack when they're working on their own stuff, but since this is at "work", why doesn't your boss hire an electrician?