Demand Load on Motors (Sewing Machines)

[bsosa]

Greetings Everyone,

My name in Bernardo and I work as a Development Engineer. I have a bunch of Sewing machines connected to Ceiling mounted Rails, and I have a bunch of questions on the things I am allowed to do (or not) based on code.
The power Rails are rated for 60 Amps at 300V. It is connected to a 220/110 three phase system. I have sewing machines that go up to 3.5 Amps @220V each.

1. Is it possible to connect more than 60 Amps of load? (I know that the sewing machines will not draw the 3.5 amps since they are provided with a clutch, nor the people sewing will use them at the same time)
2. What other options do I have on this matter?
3. What section of the code would help me on this matter?

P.S: I am an Electrical & Electronics Engineer, I would just like to keep the installation as compliant as possible with code, just need some seasoned person to give me a hint. Would really appreciate it!

 

[MAC702]

Good question. I question whether the code even applies to you, the end user, once it's all installed and operational. You may be permitted to use your installation to the best of your experienced abilities.

For example, the code will tell a designer/installer how many outlets must be provided and where, but doesn't tell a homeowner that they aren't allowed to plug a vacuum cleaner into all of them at the same time. Experience will teach them that.

 

[bsosa]

Good question. I question whether the code even applies to you, the end user, once it's all installed and operational. You may be permitted to use your installation to the best of your experienced abilities.

For example, the code will tell a designer/installer how many outlets must be provided and where, but doesn't tell a homeowner that they aren't allowed to plug a vacuum cleaner into all of them at the same time. Experience will teach them that.

The part that the code might not even apply to me in the worst part, I have no idea on how to treat each machine, I am thinking about considering that most of the time (maybe all the time) they will operate under 60% of their capacity, or something around that. It's kinda funny how these things have to be made by iterating and not by plain rules (It's a good/bad thing). Thanks for the answer, if you have any recommendations they'll be very well received, I'll let you know what I've done in a few!

Thank you, Again.

 

[Little Bill]

Greetings Everyone,

My name in Bernardo and I work as a Development Engineer. I have a bunch of Sewing machines connected to Ceiling mounted Rails, and I have a bunch of questions on the things I am allowed to do (or not) based on code.
The power Rails are rated for 60 Amps at 300V. It is connected to a 220/110 three phase system. I have sewing machines that go up to 3.5 Amps @220V each.

1. Is it possible to connect more than 60 Amps of load? (I know that the sewing machines will not draw the 3.5 amps since they are provided with a clutch, nor the people sewing will use them at the same time)
2. What other options do I have on this matter?
3. What section of the code would help me on this matter?

P.S: I am an Electrical & Electronics Engineer, I would just like to keep the installation as compliant as possible with code, just need some seasoned person to give me a hint. Would really appreciate it!

I used to be a Tech in a plant full of sewing machines. Your set-up sounds similar to what we had.
There was a feed rail running above with 3Ø power. The feed rails were split up and connected to a feed bus. The machines all had their own fuses, usually 3A-5A, depending on the motor size and other needs. Since different machines have different current draw, there isn't much way to tell what might be plugged in to a single rail at any given time. So usually a 30A OCPD fed a rail, and like was said already, you learn how many machines can run on any rail.
Most important thing is that the rail is wired with conductors large enough for the load(s) and the proper sized OCPD installed.

The rails we had used a twist lock plug and made it easy to plug/unplug machines as needed. You could set up a rail thinking it was large enough and some supervisor would come along and decide they needed 10 more machines on that rail. They had to learn the hard way on how many machines could be on a rail. My point is, if the machines get moved around, there isn't much way to know what might get plugged in and they will just have to learn.

You mentioned clutches on the machines, that sound like older AC powered motors. We had begun moving to all DC motors. You could adjust speeds on them and control them easier. Also makes less current draw since the motors are more efficient.