Shopping for a conveyor system

I'm quoting on a job for a conveyor line.
We have 17 sections of 20' conveyor, approx 1/2HP motor/drive on each.
Customer wants to be able to vary the speed of the line (one speed for the whole line).
Because of the distances, we are contemplating putting a JB and drive at each motor (350' from main panel to last conveyor).

Q: Has anyone used one drive sourcing multiple motors?
Q: Is there such thing as a 1/2HP AC drive with a built-in starter/overload?
Q: Is there a drive as above, with a built-in VFD?

I've not investigated a cheap stepper or servo, but my gut tells me it still will not be cost-effective.

Electrician wanted to get drives with a card reader or similar way to clone one drive to the other 16 - for initial setup but mainly to vary the speed. I told him to pass on that; we'll use analog.
Q: Anyone have any qualms about sending a 4-20mA signal, 350', with 17 taps?

Are they accumulating conveyors? If so, synchronousing the speeds of each one won't be as important.

Personally I'd use VFDs mounted in JBs with disconnects all linked with Devicenet or something similar.

Yes, they are vacuum conveyors carrying bottles. They do not have to exactly match in speed. +-5% is probably ok.

Yes, you can use one drive for multiple motors. You simply turn off the drives internal overload protection feature, and use a seperate overload block for each motor, which are all paralleled off the same drive.

In this app however, I worry about the distances involved. A LOT of wire will be hanging off that drive, and strange things sometimes happen when you start doing that.

You really dont need any additional starters or overload blocks if you use one-drive-per motor setup. There are drives that contain additional starters and stuff, but these I've mainly seen in the HVAC market. They allow the compressor to run at full speed if the drive fails for whatever reason. Not really what we're discussing here.

Long post short, I second what was said above about using communications to set this up and one drive/motor.

motor/drives

I'm pretty sure I saw an ad recently for a motor/drive combination in one unit. I don't remember the vendor, so search around on google to find them. Lately, I've been using AB PowerFlex drives on EtherNet/IP with good results. They provide overload protection as well.

Multiple motors per drive - it can be done. Check with your vendor or the drive documentation first.

I'd consider putting the drives in one panel, keeping the drives in one location. The construction cost of installing 17 panels would probably justify it. More than a few drives though shielded cable is recommended (more expensive wire + larger wireway). I'd like to hear other comments/experiences on doing this.

J

The one thing you have to remember, in the US anyway, is that if the motor is more then 50' (or out of sight) from the disconnect panel then it must have its own disconnect; so factor that into consideration.

That is a safety situation I have not considered or dealt with that I can remember. I know with a VFD you should not use a disconnect after it, can be detrimental to the drive. In this case if you stop one motor though you need to stop them all.

Overall I think I would look at using separate drives for each motor and using DNET or similar (as mentioned) then if one motor is stopped or disconnected all would stop. I think the drive and a disconnect should be located near the motor, that way you can feed the drive from the disconnect then to the motor.

The cost may be slightly higher but from a maintenance and safety standpoint it may be more cost effective.

rsdoran - can you point me to the code that requires the local disconnect as you mentioned? It's my understanding that a local disconnect is not required as long as the main (say a MCC bucket in a distant MCC room) is lockable.

However, your plant standards might say otherwise... Example - We typically say anything cycled more than once per shift requires one.

I will have to find the specific Article but it should be in 430. T

The issue is not where the disconnect is, the issue is people do not always go back to the main disconnect and disable motors from being energized or someone from energizing a disconnect that has been disabled.

I will see if I can find the specific article but there are always exceptions, personally rather have the disconnect at the motor where I can see its locked out.

Allen Bradley have self contained DOL starters or VSDs in their ArmorStart Range. I have 28 of these mounted at the motor on the conveyor and each has it's own builtin isolator. The units I have are all on DeviceNet, speed and starting are controlled via CIP Messaging to each individual drive.

Steve

I meant, in my first post:
Q: Is there such thing as a 1/2HP AC MOTOR with a built-in starter/overload?

I'm thinking of the AC parallel of a Quicksilver servo - motor, drive, amp - all in one.

RoTaTech said:

I meant, in my first post:
Q: Is there such thing as a 1/2HP AC MOTOR with a built-in starter/overload?

I'm thinking of the AC parallel of a Quicksilver servo - motor, drive, amp - all in one.

Click to expand...

check with Reliance. Example: http://www.reliance.com/pdf_elements/d2937.pdf

Thank you JS - that is almost EXACTLY the thing I want. 1/2HP is plenty for me; the Reliance goes from 1HP to 5HP, but depending on price, it may be worth it. At least I've a starting point for shopping.
Cheers!

http://corporate.sew-eurodrive.com/produkt/C11.htm
As long as the whole line needs to run the same speed and all of your gearboxes are identical I would definately recommend you install a single drive for this application. I think you're going to find it's much more economical to buy one 10HP drive and mount it in a cabinet with 17 overloads than buying 17 - 1/2HP drives (if there is such a thing) and JBs. It's also going to be a whole lot simpler to commission one drive than 17 individual drives and a communication network.

If you go with the single drive solution you just have to add up HP and FLA from all of the motors and make sure your drive is set to run in a V/Hz mode (sensorless vector will not work for multiple motors).

We have also been using the Allen Bradley PowerFlex drives on ethernet with great success in our workplace.

You will have to check the electrical code in your jurisdiction for placement of motor disconnects as rsdoran stated. I know that where I am the disconnect has to be within sight of the motor.

But if your married to the idea of individual drives SEW has a line of integrated gearmotors and drives. I haven't used them myself but I use their motors and gearboxes all the time and they are excellent with short delivery time on spare parts.

http://corporate.sew-eurodrive.com/produkt/C11.htm

rsdoran said:

I will have to find the specific Article but it should be in 430.

Click to expand...

Thanks... I'd like to know if I've missed something. As I said, this is something I run into quite often.

rsdoran said:

The issue is not where the disconnect is, the issue is people do not always go back to the main disconnect and disable motors from being energized or someone from energizing a disconnect that has been disabled.

Click to expand...

There might be more than one case here. By "people" do you mean operators or technicians? If operators have a reason to disconnect the motor (clear a jam, etc), then yes, install a local disconnect. If it's a motor only technicians would disconnect to service it, then I don't see a need, regardless of the distance.

rsdoran said:

I will see if I can find the specific article but there are always exceptions, personally rather have the disconnect at the motor where I can see its locked out.

Click to expand...

I agree - It's nice to have a local disconnect; however, time and money are also a factor. I don't want to install the disconnect, wire, etc. so a technician can save 50 steps every 5+ years. Doesn't make $ sense IMHO. Also, in my case, a suitable location for the disconnect is often harder to find than the money to buy it.

Justin