Automatically starting a dust collector

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conmgt

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Hello everyone,
I'm working on a woodshop that has two 3ph table saws each with their own 1ph 240V 2hp dust collectors. I need to have the dust collectors turn on/off whenever the saws are turned on/off. Right now, the dust collectors are turned on via a simple mechanical manual ON/OFF contactor at the collector itself.
I figure I can replace that contactor with a magnetic contactor like a SqD 8910 DP12. I called SqD and the tech went right to a magnetic starter with thermal overload protection.
Do I need to make that leap ($$$) if the manual starter supplied with the dust collector sufficed? I want to run an SJ cord from the saw to the collector. Would tying one end into the load side of the saw's starter and the other into the coil of the collector's contactor be appropriate? Or maybe tap into the saw's A1 and A2 terminals? I'd like to use an 18 or 16ga SJ cord but would I need seperate circuit protection since the saw and collector are on 20A and 30A circuits?
Thanks for your input.
 
You probably can't use SJ cord for this install. Take a look at 400.7 and 400.8 for uses permitted and not permitted for flexible cord.

Also review Part VI of Article 430 for motor control circuits.

Chris
 
Leave your manual starter in place to serve as your disconnecting means and motor protection. Add your motor rated contactor in series with the manual starter. You will not be able to tie a single contactor coil directly to two different power sources (you would get backfeeding). You will either need auxiliary contacts on each saw's starter, or use two new contactors (each coil wired to one saw and the contacts wired in parallel to the dust collector).
 
raider1, The collectors are on wheels and came with power cords and plug into 240v recpts. Also, the saws came with flexible power cords. The flex cords are needed to allow 360 degree unobstructed floor space around the machines. As far as 430VI, how about a 2 pole fuse block?

jim dungar, The manual starter has no overload protection in it that I can see. Am I missing it? Is it in the TEFC motor? Also, I had no plans on using both circuits on the coil, I was just going to power the collector's contactor coil with the saw's coil circuit only or vice versa, use the collector's circuit to power it's contactor and the saw's...disconnect to wires from the saw's coil leads from L1 and L3.
Does that address the backfeed concern?
 
My oops, I did not notice you had one dust collector per saw.

It is possible that your 2HP motors have integral protection, in which case put the new contactor in series with the existing manual starter and wire the contactor and saw coils in parallel.
 
I designed a dust collector controll that does not need to be wired directly to the shop tool or starter. I used a current sensing switch (see the link below) to energize the coil of an interposing ice-cube relay and energize the coil of a HP rated contactor for the dust collector. The CT is rated up to 100A so you can run multiple tools through the same CT switch. You can also parrallel CT outputs in order to control more than 100A of shop loads. I installed a time delay relay in the contactor control circuit to delay dropping the dust collector a few seconds after the shop tool is turned off so the dust collector evacuates all the saw dust from the collector ducts. I also incorporated a three position switch for on/off/auto control. If the saw and the dust collector circuits are fed from the same panel this is a great way to control the collection system as you don't need to run control wires all over the place. All the parts fit into a 10x8x6 hoffman box with a back plane and hinged door. The can gets located next to the power panel and you put the CT in the power panel on the load wire and run the dust collector feeder through the control can. I installed one in a friends cabinet shop and he loved it. He was able to turn his dust collector on and off automatically each time he used his shop equipment. Be happy to share more details if your interested.........

http://www.crmagnetics.com/newprod/ProductView.asp?ProdName=CR9350
 
jimday, Yes! I've had that CT switch thing in my head for about a year but couldn't get people to understand what I was looking for. Thanks for the reply. It solves a lot of issues for me.
I definitely would like to hear some more details. Also, I didn't mention in my question that I wanted to do a delay on make and a delay on break timer. One thing at a time, you know.
Anyway, I didn't want to have the collector start with the saw simultaneously and as you pointed out, have the collector run for a few afterwards. ABB makes a great line of very small and flat timers that are called Programa Cubes. They easily fit into a 4x4 box.
Tell me more about your solution

Ed
 
conmgt said:
....that CT switch thing in my head...
Click to expand...
They are called current switches. I have used some from Relay-In a-Box (RIB) and from NK Technologies (whose a brand labeled by others).

If you want timing, I would use a "smart relay" (a programmable device usually with 6-8 inputs, eight timers, and four outputs - kind of like a PLC)
 
jim dungar said:
They are called current switches. I have used some from Relay-In a-Box (RIB) and from NK Technologies (whose a brand labeled by others).

If you want timing, I would use a "smart relay" (a programmable device usually with 6-8 inputs, eight timers, and four outputs - kind of like a PLC)
Click to expand...
i don't think he wants or needs to get that technical and expensive with it.
 
The RIB stuff is all low voltage on the control side and looks quite a bit more complicated not to mention $$. Looks like you need at least 3 of their parts to sense and control one load from another. The solution I came up with uses simple off the shelf parts and can be done for less than $200 not including install....
 
My contact info:----------
j. dungar, I'll google RIB. PLC sounds pricy, ProgramaCubes are about $70 each, but I'll goggle that too.

http://library.abb.com/global/scot/scot260.nsf/veritydisplay/58013a2067c1f7bf8525709e006f5428/$File/KSPDGen.pdf
 
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jimday said:
The RIB stuff is all low voltage on the control side and looks quite a bit more complicated not to mention $$. Looks like you need at least 3 of their parts to sense and control one load from another. The solution I came up with uses simple off the shelf parts and can be done for less than $200 not including install....
Click to expand...
Ribs aren't all low voltage. They are no different than icecube relays except for that they anre inside of a box and they mount with a 1/2" hub. They have them for different voltages. After all that's why one needs a relay to begin with. For different voltages interacting with each other.
 
conmgt said:
raider1, The collectors are on wheels and came with power cords and plug into 240v recpts. Also, the saws came with flexible power cords. The flex cords are needed to allow 360 degree unobstructed floor space around the machines. As far as 430VI, how about a 2 pole fuse block?
Click to expand...


This has no bearing on the wiring method you are suggesting that you wan to use.
Those units may be listed for the wiring method they came with.


You are field wiring an entirely different setup and will be required to use a Chapter 3 wiring method, as Jim has mentioned.
 
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It's all 240 on this job; coils,relays. After I switch the service from
2ph 4 wire to 3ph, it'l be 208.

It should've been Steelers/Eagles (The Turnpike Tussle) in the superbowl but our defense didn't show up last Sunday.
 
conmgt said:
It's all 240 on this job; coils,relays. After I switch the service from
2ph 4 wire to 3ph, it'l be 208.

It should've been Steelers/Eagles (The Turnpike Tussle) in the superbowl but our defense didn't show up last Sunday.
Click to expand...
Yes but you have other voltages available, such as 120. The control circuit in a starter is usually 120. You could put in a control xformer and use 24 volts for controls. Besides earlier in your first post you said the saws were 3 phase. So I guess you have a high leg right?
 
There isn't any 120 in the saw or collector's circuit's conduit. I'd have to run a neutral back to the panel. The 3ph loads are on phase changers...2ph to 3ph changers are popular in Philly. I'm going to need a 3ph to 2ph for the elevator someday...much easier than swapping the motor out. It's about 80yo, 600lb, and works fine.
 
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