Phantom 40V

[Shuntme]

Hi all. Newbie here needing help.
I Have a electronics smart Actuator(LimitTorque MXB) that is not responding to the remote commands as it should due to the presence of a Phantom 40V-N/GND (inductance/capacitance). However if I remove this phantom 40V then the actuator works properly. This electronic smart actuator is replacing an old actuator(electro-mechanical controls) so the phantom 40V did not affect it's(old) operation.
External supply/control wiring:
1. 230V 3-phase electrical panel + Neutral + GND
2. 120V in the panel(Breaker) for a sump pump
3. 4 of 230V actuators(original) with separate individual 120V controls supplied by an internal TRX in each actuator.
4. 230V Power wires(separate breakers) and #12 control wires(remote) run in same pvc conduit then split to each actuator at a J-box
5. Actuator A & B do NOT have phantom voltage
6. Actuators C & D have this phantom 40V - Neutral/GND

Actuator C don't care about the 40V cause it is still an electro-mechanical control system. Actuator D is now replaced with the electronic Smart valve and having issues with the phantom 40V -N/GND.
Question: How do I get rid off/minimize this 40V so it does not affect my Electronic Smart Actuator?
I am thinking a series resistor might work????????
PS: The Remote momentary Stop/Open/Close commands are maintained in the Actuator controls. If I send an Open command(remote) by pushing the Open button and let go(momentary), the actuator will continue to open until I push the Stop button or it reaches the fully open position. I can get rid of the phantom 40V by turning off the breakers to all 4 actuators but that's Not an option. lol
Appreciate all your inputs
Thank you

 

[winnie]

Don't think series resistor, think shunt resistor.

The Electronic Smart Actuator has a high input impedance and doesn't significantly load the control line, so parasitic induction/leakage/capacitance can create voltage on the line. You need to add some sort of load in parallel with the ESA to 'pull the voltage down' so that the ESA doesn't see an active input.

-Jonathan

 

[Shuntme]

Don't think series resistor, think shunt resistor.

The Electronic Smart Actuator has a high input impedance and doesn't significantly load the control line, so parasitic induction/leakage/capacitance can create voltage on the line. You need to add some sort of load in parallel with the ESA to 'pull the voltage down' so that the ESA doesn't see an active input.

-Jonathan

Hi Jonathan.
Appreciate the quick response.
1. Do I calculate the shunt resistor value based on the phantom 40V or the 120V control voltage.
2. Do I shunt it at the Stop button or a shunt at each of the Stop, Open and Close Command lines
3. Also, the Stop button line/conductor supplies the 120V power to the ESA
4. It's a standard Stop(NC) push button that sends the 120V to the ESA but also power to the Open(NO) command and the
Close(NO) command signals

Thank you

 

[winnie]

You calculate the shunt resistor for several cases

1) It has to have a low enough resistance to pull the phantom voltage down enough that the ESA doesn't activate. That calculation depends on the supply voltage for that phantom and the impedance of the phantom connection. You may need to try several different resistors to see what will work.

2) It has to be high enough resistance to not excessively load the circuit when you are intentionally suppling 120V down the line to the ESA. You need to figure the power dissipation of the resistor and the voltage rating of the resistor.

I don't have enough experience with 120V control circuits to help further; my experience with phantom voltage issues is in logic level circuits. You might consider a useful intentional load such as an incandescent indicator light near the ESA.

 

[ptonsparky]

We would use about any small load. Ice cube relays.

 

[Hv&Lv]

You might consider a useful intentional load such as an incandescent indicator light near the ESA.

I’m not a controls man, but I was thinking the same thing about something like a 20W incandescent bulb as you suggested

 

[Shuntme]

We would use about any small load. Ice cube relays.

Thank you
Will give that a shot

 

[Shuntme]

I’m not a controls man, but I was thinking the same thing about something like a 20W incandescent bulb as you suggested

I'll try that too.
Thank you

 

[don_resqcapt19]

We would use about any small load. Ice cube relays.

We had similar issues with the controls for VFDs and at first we used the small ice cube relays, but as they changed the designs of the VFD, we had to use a larger relay to get enough load. It appears as they made the VFDs physically smaller they were more sensitive to "phantom" voltage. We have also used transformer type pilot lights for the same purpose.