Controlling Motors and Heaters

Hello All,

I am a undergraduate student of Mechanical Engineering working on my senior project. We need to get a power supply for eight 1500 Watt Cartridge heaters that run on AC, two 24 V DC 100W motors, a 16 W heated wire and an air compressor which will probably not be hooked up to the power supply. This leads me to my first question: How can I power all of this? We are looking at Transformers, but am worried that this may not be enough or very expensive.

The next question involves controlling them, For the Heaters we have been looking at solid state relays so we can control them with the Arduino board and will have thermocouples to monitor their temperatures. The motors we could control the same way with a relay, but if someone has a better idea of what to use for this, I would love to hear it. The heated wire just needs to turn on and off with a switch of some kind. The valve of the compressor needs to be controlled but this is a newer addition and is still being researched. I am not as worried about the programming as I am about the feasibility of this kind of project. Since my knowledge of electrical systems is limited I am more just looking as to what is out there. I have been looking around on the internet and have found the information less than helpful. One thing I am sure about is that the Arduino products are what I want to work with, and the information on in is incredible.

Thanks

I am a undergraduate student of Mechanical Engineering working on my senior project.

I am an ex University Lecturer (U.S. == Professor) in Physics and Electronics, with 45 years of experience in electronic systems and if I was doing this myself I would be most apprehensive.
Considering:-

Since my knowledge of electrical systems is limited

I wonder if your supervisor knows what you are trying to do?

I would not consider attempting to make any of this stuff yourself but to but in modules. Have you any idea how much this is going to cost?

We are looking at Transformers

What voltage do the heaters run at?

but am worried that this may not be enough

I don’t think you have any option here, you don’t get many high power AC batteries.

or very expensive

Yes the whole project is very expensive.

We need to get a power supply for eight 1500 Watt Cartridge heaters that run on AC

I suggest the AC power outlets on your wall.

Really, the question is "what are you doing and why do you need a 'power supply'"? Why can't you just connect the heaters up to wall power, with a switching element (like a relay) to control them?

Note, too, that 1500W is about 12.5A at 120V, which is about the limit of a typical household fuse circuit, so if you need 8 of them you had better plan to be somewhere other than a typical household. Or at the very least talk to your facilities manager and figure out how your circuits are fused and whether you can actually draw 8x1500 = 12kW of power.

Any more (specific) details on your project and its goals would be quite interesting.

-- The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected

What voltage do the heaters run at?

So the heaters run on 240v and as design continues to evolve it may only be 6 heating elements.

what are you doing and why do you need a 'power supply'"?

It will be run at our university and we have yet to ask anyone how much power we can draw from the manufacturing center. We have considered just plugging them in and it seems that it is probably our best option, but as far as how to make that work, we are still trying to figure that out. We have found step up/step down transformers that just plug into the wall and have a few outputs both 240 and 120 that might work, maybe getting two of them?

I wonder if your supervisor knows what you are trying to do?

Our teacher doesn't really understand our project and we just submitted our report stating our power requirements so we will see what his input is. We have also made an appointment with a teacher from the EE department for after thanksgiving to get more input.

Any more (specific) details on your project and its goals would be quite interesting.

We are designing a machine that will take used plastic shopping bags and draw them through a heated section to seal the outsides making a "packet" of bags. If it is thinner it can be used as padding or even molded into a shape, if its thicker it can be used for insulation. The hope is to create an automated process that will reuse some of the wasted plastic in the world.

We are designing a machine that will take used plastic shopping bags and draw them through a heated section to seal the outsides making a "packet" of bags. If it is thinner it can be used as padding or even molded into a shape, if its thicker it can be used for insulation. The hope is to create an automated process that will reuse some of the wasted plastic in the world.

So how do people recycle plastic bags at the moment and what is your improvement upon this? Have you done any kind of energy balance calculations to work out what your energy saving will be?

Good point. In France, plastic carrier bags used to be printed with how long they would power a 60W light bulb, if they were burned.

So how do people recycle plastic bags at the moment and what is your improvement upon this? Have you done any kind of energy balance calculations to work out what your energy saving will be?

The project is called upcycling as opposed to recycling. Currently plastic bags are shredded and then melted down to pellets and then reused. This is a very energy intensive process and most plastic bags have stabilizers that are added which make them even more difficult to recycle. We have not yet completed energy balance calculations but it will be part of our final report. We are also looking at this as more of a third world country solution or lower income solution where there are few recycling measures in place.

In the "third world" very little goes to waste. Most things are re-used. This would include, for example, dentures which you can buy second hand (mouth) in the market. Lathes are often extremely skillfully powered using a bow with the blade being operated by foot, 1kw is usually not readily available. Go to a place where plastic bags are returned grab a random handful. How are those bags, some of which will be old, wet dirty and full of holes, be fed into your system?

I don't wish to be critical of your idea because you have given little information about it but I think you yourselves need to take an objective look at its practicality.

quarkyquasar: Currently plastic bags are shredded and then melted down to pellets and then reused. This is a very energy intensive process ...

Given that your solution will be using upwards of 12KW, I doubt that you can claim superiority there. Given the extraordinary power consumption you're predicting, I wonder what benefit you expect to achieve.