Control circuit

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jes25

Senior Member
Location
Midwest
Hey guys, I have a customer with some unique requirements to control his lights. I'm planning on putting a timer and a motion in parallel with the motion being ran through a holding contact on the lighting contactor. My question is with the timer and motion being in parallel the "load" contacts of the timer / motion will be hot at times when the device's contacts are open. Is this a code violation?

If interested this is how it will work:

Push timer: contactor pulls in for 10 minutes including the holding contact activating the motion circuit

Motion on court: Motion on court within 10 minutes continues to hold contactor closed

No motion and timer expired: contactor opens and lights go off

Lights stay off until timer is pushed again
 
T

templdl

Senior Member
Location
Wisconsin
jes25 said:
Hey guys, I have a customer with some unique requirements to control his lights. I'm planning on putting a timer and a motion in parallel with the motion being ran through a holding contact on the lighting contactor. My question is with the timer and motion being in parallel the "load" contacts of the timer / motion will be hot at times when the device's contacts are open. Is this a code violation?

If interested this is how it will work:

Push timer: contactor pulls in for 10 minutes including the holding contact activating the motion circuit

Motion on court: Motion on court within 10 minutes continues to hold contactor closed

No motion and timer expired: contactor opens and lights go off

Lights stay off until timer is pushed again
Click to expand...
Have you considered a small PLC?
 
T

templdl

Senior Member
Location
Wisconsin
jes25 said:
Yes. Not a good option for us though.
Click to expand...

Is there a way that you can draw a schematic/wiring diagram and attach a picture of to you post? Then there would be no misunderstanding of your verbal description.
I would venture to guess that what you are proposing to do would work. But your reference to "load contacts" concerns me as it implies that everything connected to the load contacts is hot and closing the contacts completes the circuit. It may be like light bulb by wiring one side of the light bulb to the line and putting the contactor on the neutral side which doesn't make any sense..
This is why providing your proposed wiring diagram would be a big help.
 
T

templdl

Senior Member
Location
Wisconsin
jes25 said:
Here it is
Click to expand...

Even though you schematic is incomplete regarding the operation on the timer and motion detector I see no issues what so ever in you wiring schematic. It looks just fine to me with no issues what so ever.
I don't know if you have this installed in an enclosure and if so do you have it configured such that the door can not be opened unless a disconnect is placed in the open position to disconnect power from the circuit. I believe that you have 480 to the contactor but do not show any OCPD that would also be used as a disconnect feeding the contactor. The 120vac for the pilot devices could be run through a N/O (a) contact which will be open when the OCPD is open. That's the only other details that I would address.'
 
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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
templdl said:
Even though you schematic is incomplete regarding the operation on the timer and motion detector I see no issues what so ever in you wiring schematic. It looks just fine to me with no issues what so ever.
I don't know if you have this installed in an enclosure and if so do you have it configured such that the door can not be opened unless a disconnect is placed in the open position to disconnect power from the circuit. I believe that you have 480 to the contactor but do not show any OCPD that would also be used as a disconnect feeding the contactor. The 120vac for the pilot devices could be run through a N/O (a) contact which will be open when the OCPD is open. That's the only other details that I would address.'
Click to expand...

Or at a minimum indicate that the insides of the box get power from two different supply circuits, both of which need to be de-energized before working on the contactor.
 
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templdl

Senior Member
Location
Wisconsin
GoldDigger said:
Or at a minimum indicate that the insides of the box get power from two different supply circuits, both of which need to be de-energized before working on the contactor.
Click to expand...

Good point.
Yes, we used to attach a bright yellow sticker to indicate that there is a separate source supply.
 
beanland

beanland

Senior Member
Location
Vancouver, WA
WHOA!

WHOA!

This control has a flaw! If the timer is closed, closing the contactor, the motion detector contact is a dead short across the 120VAC.

The motion control contact needs to be in series with an aux contact and those in parallel with the timer. The contactor coil should have the only connection to the neutral of the control circuit.

Motion sensors may not like being turned on and off a lot. Suggest leaving the motion sensor continuously powered but route its output through the aux contact and then to the coil.

When both the timer and motion detector open, the lights will go off. The timer will turn the lights on and the motion detector will keep them on.
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
beanland said:
This control has a flaw! If the timer is closed, closing the contactor, the motion detector contact is a dead short across the 120VAC.
Click to expand...
Take another look at the schematic! Although the physical layout of the contacts on the page is a little strange, both the motion detector contact and the timer contact connect only between 120 and the high side of the contactor coil.
 
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