Motion Detector with Contactor

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Shade_M16

Member
Location
Florida
Occupation
Apprentice electrician
Hey y'all, so I have 16 2bulb led fluorescent lights(pulling about 6.2amps total) under a carport at my house that I want to have activated by a motion detector. I installed a contactor in line so all the load isn't going though the motion detector itself. Here is the one I bought. https://www.amazon.com/dp/B001KGSJ74/ref=cm_sw_r_cp_apa_i_KcEJFbDWHG29P

The problem I'm getting is when it turns on the contactor will chatter on and off and the lights flash until I unplug it. I'm curious why that's happening and what would be a fix for that. Idk if I need a different kind of motion detector or contactor maybe? Would there be anything I could install in line before contactor that would prevent it from doing that? Thank you for any help.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
201019-1545 EDT

Shade_M16:

Really bad datasheets. But some probing shows that it is an AC coil.

First: assuming the contactor is 120 V 60 Hz coil, then apply 120 V 60 Hz directly to the coil. Does that work as expected?

If so, then your problem is probably inadequate resistive loading on the motion detector. Put a 100 W incandescent bulb in parallel with the contactor coil, and see if things work. If it works correctly, then determine the smallest wattage bulb that will cause it to work. If 100 W is not large enough try a 250 W bulb.

When you determine the smallest wattage bulb that will make things work, then calculate its resistance.

The next best step will depend upon that resistance, and its wattage.

.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Not enough seal in current from your very tiny motion detector relay.
either get something like a cube relay to pull that one in or wire that one on a bulb circuit.
That relay doesn’t pull much at all. See if it works with an on off switch. Add a 100 watt bulb to the coil circuit and see if it chatters.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I would find a motion detector with an inductive-load rating or a relay-contact output, and omit the contactor.
 

Shade_M16

Member
Location
Florida
Occupation
Apprentice electrician
Alright guys very sorry for the late reply on this, I ended up hooking the incandescent bulb (60w) in line and the lights come on and everything works perfectly. I really appreciate the help from gar and Hv&Lv! Awesome idea yall.
 
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