Jumping a 110v off 230 feed?

[camm]

I'm starting the wiring of our new PRS Alpha with a single phaze spindle. The question is, can I just jump a 110v leed off of the 230v input for the spindle?
Or do you have to run a 110v leed into the control box?
i would not like to have two cords if I do not have to.

thank you.

[scottj]

This is not recommended and in most cases when we’ve seen the incoming power configured this way it is problematic, usually manifested in the form of communications breaks, jumps or sudden pauses and false triggers of limit switches and e-stops. It is a much better solution to run the separate 110v circuit to power the machine.

[harryball]

If you are determined to have a single power feed to your bot you should bring over a suitable power connection and install a sub panel on the bot itself, then break out what you need. I put my sub panel on the wall and ran the required cable over on individual breakers as required.

I guess the answer is yes you can but no you should not pull 110V off a 220V leg. For one thing, overload protection could be compromised if the 110V load should have a lower amperage rated breaker it will actually have the rating of the 220V breaker on the one leg. I also second what Scott said, by running on the same breaker you could be introducing noise in the circuit for the control board.

/RB

[camm]

Thank you for that advice!

[richards]

I'm a little confused about why there is concern about using a 240VAC line (in North America) to supply 2-120VAC lines. Our power companies use two 120VAC lines to make one 240VAC line. The lines consist of a 120VAC line (Black), a second 120 120VAC line (Red) and a neutral. The Black line and the Red line are 180-degrees out of phase so that that peak-to-peak we get 339VAC or 240VAC RMS.

Take this next part with a grain of salt. I am not an electrician. I build process control computers, but I rely on electricians to properly prepare the site before I install my stuff.

The purpose of a fuse is to keep you from burning down your building. All wire has some resistance. Resistance in an electrical circuit causes some heat. A fuse or breaker keeps the heat from getting hot enough to cause damage.

As I understand it, you are required to have a fuse in your breaker box matched to the wiring attached to that circuit. For example, 10-gauge wire is normally rated at 30A, 12-gauge wire is normally rated at 20A and 14-gauge wire is normally rated at 15A. So, if you have a 15A fuse in the line, you MUST have wiring that is at least 14-gauge to carry the current allowed by the fuse.

That brings us to a controller.

As long as the wiring to the controller can handle all the current allowed by the panel, you are safe. When you sub-divide a circuit inside the panel, you MUST furnish a fuse or breaker IF the wiring inside the controller is smaller than the wiring going to the controller. For example, let's say that you have a circuit that only needs 1A of current at 120VAC. As long as you have a fuse or breaker that will blow if more than 1A of current starts to flow through that circuit, you only need wiring that is guaranteed to carry 1A - after the fuse.

It seems totally reasonable to use a 240VAC single phase circuit to power a machine that requires a lot of current. If you separate the two 120VAC lines properly so that each line carries about half the current, things should work very well.

Cross talk and electrical noise are not caused by having two 120VAC lines inside your control box; they are caused by not properly grounding your lines and by mixing high-voltage devices with low-voltage devices. A high-voltage device might be something like a router. A low-voltage device might be something like a sensor. A low-voltage TTL device probably works with 5VDC. What most people don't know is that a 5VDC TTL circuit is guaranteed to work from +0.7VC to 2.2V. The math says that the circuit can toggle between on/off if the voltage range is only 1.5VDC. If your TTL signal lines are mixed with your high-voltage lines, 1.5VDC can easily be "imposed" onto the TTL lines, after all, the peak-to-peak voltage on a 120VAC line is really 170VAC. A little 1.5V signal can easily get lost when a strong 170VAC signal starts up.

In industrial wiring, it is common practice to split single-phase 120VAC lines from a 240VAC line. It is common practice to run low voltage sensors near high-voltage devices. A good layout makes it all possible.

In other words, don't be afraid of electricity. Take the time to learn about it and then learn how to make it work for you.

[bcondon]

Well, having worked with electricity for 30 years, I would ONLY recommend separating the control and spindle circuits.

The installation makes complete sense to anyone installing industrial equipment.

If you mix this, then you would need to have a 60 amp double pole breaker and wiring for 60 Amps to the machine...

The 60 Amp breaker is protecting the spindle (which should be protected for 30 A) and the control system (which should be 25A) because one leg of the 120/240 would support BOTH units (30A spindle + 25A control)...

You just spent a lot more money and reduced your protection.

I just installed mine with the recommended setup and she works like a champion!