Fixing Capacitive Coupling (Phantom Voltage) issues with pull down resistor

[Shuntme]

3000 ft is in line with my estimate for how long the wires would need to be for the capacitance to cause that much leakage. (There were very wide error bars on my estimate, but at 3000 ft it is totally plausible that 120V could cause a couple of mA of capacitive coupling.)


Are the 120V secondary coils grounded? The neutral should not be floating at 40V to ground unless you _intend_ to have an ungrounded system.

With 3000 ft of wire, that is totally to be expected. The capacitive coupling would be more than enough to light LEDs.



Remember that 'Phantom voltage' is a _real_ voltage. 'Phantom' in this case doesn't mean that it is some ghost version of voltage, simply that this voltage is derived through a high impedance pathway, and goes away if you have a low impedance load or meter. Don't think of 43V of phantom voltage, think instead of 120V in series with a 46K capacitive leakage path. That leakage path forms a divider with your load impedance. This is why the old electromechanical actuators didn't have a problem; they were very low impedance and that swamped the leakage impedance. The new actuator has a high impedance input, which is why you are considering adding a parallel resistor to lower the total load impedance.


Agreed.


Spitballing here:

1) If some of your 120V control circuits are ungrounded, then you need to think of the conduit as a possible source of phantom voltage. Every bit of metal in the conduit, including the conduit itself, forms a capacitor with every other bit of metal. If your neutral (which is also your signal reference voltage) is floating at 40V, then the conduit is 'pulling' your signal lines away from the neutral potential.

2) Will your new actuators function with _DC_ control signals? How about your LED indicators? DC would eliminate the capacitive coupling form of phantom voltage.

Totally agree. I will open up the #39 actuator and check the 120V transformer if it's Gnd. #38 has been torn down so I can't tell. But like I said, #40 & #41 are same set up with #38 and all control wires run in same conduit but #40/#41 only have 2.2V phantom on the seven control wires to Gnd/N. I quit scratching my head on this as I can't afford to lose any more hairs off the top, lol. I am focusing on getting my new electronic actuator controls(Remote) to work properly.
DC external control is out of the question as it require engineering and industrial codes regulations. I have some follow through mentioned above when I can get to them. I'll post update. Appreciate the precious time you're investing in my adventure. Thx
PS: A similar situation happened about 3 months past with one of our AC units controls. AC stopped working(10yrs) called AC company and their technician said we have faulty wiring cause he was getting 460/230V on the control control transformer but only 40V to Gnd. I showed the technician that he was getting the 230V at the trx but since the secondary was not Gnd it's a floating neutral but the control relay is somehow dumping the 230V so it's not getting the required voltage. Same wiring we have had for 10yrs. He found burnt relay contacts. Replace and Voilla!