How can I make this work?????????

[chevyx92]

Existing setup on paint booth. Exhaust fan in paint booth is controlled by a start/stop which controls one side of the coil(208v) of a 3 phase starter, this starter then feeds the exhaust fan. This starter and controller is located outside the booth on the wall behind it. Here's what needs to happen. Install door switches with NO contacts wired in series on all doors of paint booth so that if the paint booth door opens it shuts off the exhaust fan. Sounds simple right. Well I have installed the door switches and placed them in series with one side of the 208V coil. Problem is doors need to be closed before you can push the start button, once you turn it on and then walk back over to the paint booth, open the door to enter, fan shuts down. And they don't want "JUST" the door switches to operate the fan. They want the option of start stop. How can this be done without installing a start/stop in the booth? (if you can even do that legally) Sorry if this is a bit long.

 

[marissa2]

Maybe a on-delay timer in the control circuit.
Lou

 

[chevyx92]

Maybe a on-delay timer in the control circuit.
Lou

Good thought, I was thinking of that too.

 

[ronaldrc]

What about putting another toggle switch in parallel with the NO kill switch inside the booth
and after you enter the booth and close the door then turn off the toggle switch.

 

[augie47]

my first thought would be to change the operation to a two wire control using an on/off switch in place of the start-stop button.

I have to ask..did you note 516.3(C)(4) in installing your switches ?

 

[chevyx92]

my first thought would be to change the operation to a two wire control using an on/off switch in place of the start-stop button.

Customer doesn't want it that way.

I have to ask..did you note 516.3(C)(4) in installing your switches ?

Yes I did.

 

[chevyx92]

What about putting another toggle switch in parallel with the NO kill switch inside the booth
and after you enter the booth and close the door then turn off the toggle switch.

If you did this and forgot to shut the switch then even if you opened the door the fan would still run which is not what is suppose to happen.

 

[LarryFine]

Okay, how's this: wire the door switch so it activates the starter like a jog button. Master toggle switch outside, booth door closed to activate contactor, don't use the latching contacts.

 

[chevyx92]

don't use the latching contacts.

So the latching contacts toward the back of the starter dont have to be used then? Can just leave them alone and just put power to the coil and it will still work properly?

Okay, how's this: wire the door switch so it activates the starter like a jog button. Master toggle switch outside, booth door closed to activate contactor,

How does that still give me pressing the start button which is outside the booth, then walk over into booth close door and have fan run but if you open door it needs to kill power to the fan. I'm thinking there's only 2 ways. A time-delay on the control circuit or a start button inside the booth. Because the door can't solely operate the fan. Reason is that sometimes they do sanding in the booth and don't wan't the fan running. Now if they're painting they want to turn fan on but as soon as a door in the booth opens the fan must be killed. Has part to do with fire suppresion inside the booth.

 

[LarryFine]

So the latching contacts toward the back of the starter dont have to be used then? Can just leave them alone and just put power to the coil and it will still work properly?

The typical latching contacts are in parallel with the start button. Wire it to operate like a standard contactor, no latch.

How does that still give me pressing the start button which is outside the booth, then walk over into booth close door and have fan run but if you open door it needs to kill power to the fan.

Reason is that sometimes they do sanding in the booth and don't wan't the fan running. Now if they're painting they want to turn fan on but as soon as a door in the booth opens the fan must be killed.

Place a toggle switch and the door switch(es) in series. If the toggle is off, no fan. If the toggle is on, fan only with all doors closed.

 

[benaround]

How about an air activated switch, like they use on hot tubs, install that inside the booth

back to back with the starter?

 

[Cow]

Place a toggle switch and the door switch(es) in series. If the toggle is off, no fan. If the toggle is on, fan only with all doors closed.

I agree. Larry's way is the easiest and uses the fewest parts.

I'd probably pull the start-stop buttons out, plug one hole, and install a 2 position selector switch in the other.

 

[quogueelectric]

Maybe call the paint booth manufacurer and ask them what they recommend. You change the factory wiring and you just bought all the liability of something bad happening that you didnt think of.

 

[iwire]

I agree. Larry's way is the easiest and uses the fewest parts.

I'd probably pull the start-stop buttons out, plug one hole, and install a 2 position selector switch in the other.

But IMO it does not do what he wants.

 

[Doug S.]

Put the on / off control in the booth. This can be done remotely via several simple mechanisms. ( Rope, Through-wall PB, and the like. ) Think mechanically for this avenue, not electrically.

Otherwise spend the cash and go exp. proof, or with power limited stuff.

 

[LarryFine]

But IMO it does not do what he wants.

What's missing?

 

[benaround]

They have intrinsically safe switches now.

 

[benaround]

They have magnetic switches also, up to 240 volts rated.

 

[Mvillines]

My wife knows nothing about electricity but says she has a solution. Install an entrance door and a separate exit door. Design the entrance door where if would be difficult to open from the inside with a nice EXIT sign on exit door that is wired to shut off the blower. I don?t know the size of the paint booth or if it is in the construction stage but said it may be possible and I?ll give them your suggestion. I also told her this is an electrical forum and this may insult all of us in the electrical trade.

 

[chevyx92]

My wife knows nothing about electricity but says she has a solution. Install an entrance door and a separate exit door. Design the entrance door where if would be difficult to open from the inside with a nice EXIT sign on exit door that is wired to shut off the blower. I don?t know the size of the paint booth or if it is in the construction stage but said it may be possible and I?ll give them your suggestion. I also told her this is an electrical forum and this may insult all of us in the electrical trade.

What????