Up here in Canada 3 phase 220 is typically wired with 3 black and 1 white wire. The 3 black are actually all 120 so taking one of them and the white neutral will give you the 120 you want.
Double check with an AC voltmeter.
You may want to use a flow control on the pneumatic side of the cylinder to prevent the spring from slamming the gate closed.
Below are some links so you can get a better picture.
Thanks for the above reply. I didn't think of using just a 120v relay off the 3-phase. For some reason 220v got stuck in my mind.
With Nordfab gates costing about 400 bucks each, this is a cheap and quick alternative. Looks like the whole thing can be done under 50 bucks.
The air cylinder link also has controllers if you scroll down for under 10 bucks (I think). I'd definately use one.
Here's my main concern: will tapping off the motor reduce the amps to the motor, or will the motor simply pull more amps? I don't know enough about electricity to answer that.
DUH...pasted the same url twice above.
Here's the link to the pneumatic cylinder:
Here's the original youtube video so you can get an idea how this whole thing works. My system is a lot simpler:
Tapping off the motor legs will not hurt the motor. Many machines have integrated electricals that draw off some power.
On 3-phase just use a standard 220v solenoid and grab power from either pair of legs. If you also have a neutral wire going to the machine for some reason you can use a 110v solenoid. If you are using a phase converter it might be better to avoid the generated leg though.
I have a shop full of these types of air cylinder activated gates I've put together over the years. All of them open when the motors start and turn on the dust collector as well. Some are double acting cylinders and others are single acting with a spring (usually just a small bungee cord) return.
Automatically turning on the dust collector is very easy via simple magnetic switches installed on each blast gate. When the gate opens the magnet moves next to the magnetic switch and closes the circuit.
Then a relay is installed at the dust collector which will complete the power circuit to the dust collector motor when the relay contacts close. The relay can have a 24v AC coil so you can power it from an inexpensive door bell transformer. Run the coil circuit through the magnetic switches on the blast gates and the collector motor will turn on when the blast gates open.
This type of automatic dust collector relay switching is most easily done on a dust collector motor that has a simple on/off switch. It can also be set up on collectors with magnetic switches but this requires a more complicated wiring scheme. I have set up both types of systems in my shop.
Since you have to run something between the machine and the blast gate, why not run a pneumatic tube to a control cylinder, operated by a manual valve like the one in the link below?
Wow, you just made my life way easier.
This is a real slap in the forehead moment: why didn't I think of that (it's why we have these forums...thanks)
It even has push connectors.
I noticed it is also "venting." I'm assuming this means that when I switch it off, it will vent off the line pressure so if I use a spring return pneumatic cylinder, the gate would close when I turn the dial.
I like this setup way better because I like to open the gate before I switch the collector on. And the collector is big enough to power two machines, so I can just leave the collector on and open and close machines as I use them. Much more productive that way.
I just installed a double acting system (like the youtube system) in my shop with 8 blast gates in 2 rooms. I used 5/16" Bimba cylinders and a 5 way pneumatic solenoid. The system runs on 12 VDC. There is a latching push button at each machine. When the button is pressed, it lights up, activates a small printed circuit style DPDT relay. The pneumatic solenoid is activated by one of the relay contacts and the other contact energizes a larger power relay at the dust collector. The blast gate opens and the Dust collector turns on.
Last weekend was the first time the system was operational. The blast gates slammed open and slammed closed with 20 psi. I ordered flow control valves which are being installed this weekend. Hopefully the slamming will be reduced.
Another issue I have is when 2 or more push buttons are on. The respective blast gates stay open until all the buttons are turned off. I'm installing a diode at each station to prevent the feedback from the other switches.
The parts ran about $1,200.00 and I have about 45 hours into it. The guys seem to like the system so far.
I installed the flow controls at the cylinders today. They work like a charm.
The diodes took care of the feedback from the other switches too.