Pilot Light Still Glow On the Off State

Can you give us a part number for the pushbutton? Better still, a link to the datasheet?

push button part#PA2 200/1, pilot light # PALAMPR380A. heres the detail. i use a zelio programmable relay controller,with digital input and relay contact output. wired the push buttons (start/stop) with pilot indicators approx. 10 meters from the control room where the zelio is mounted. i just wonder when i use the telemecanique LED pilot lights (same specs except for the brand),regardless of situation/installation/location,it doesn't glow, but since i started using the carlo gavazzi, these glowing problem start to exibit. i contacted the supplier, but no feedback/solution given to date, and this is only showing on their illuminating push button, but on their LED pilot light which is not integrated in their PB, no problem at all. thanks

Writing about 380V pushbutton and pump motor starter made it seem like the simplest situation of an AC 380 volt motor starter, hence my post, #2. Now you tell us a programmable controller is involved! Please note controller relay outputs sometimes have a "spark suppressor" capacitor built-in across the contact (over 0.01 microfarad, 10000 pF in value). In an AC circuit, this can conduct a significant current. Even with controller DC outputs, one cannot be sure switch leakage can be ignored - some have significant leakage, others actually have "circuit continuity check" function which feeds a current into the load while off. When the supply to these suppressed contacts is 110 VAC, I have had to fit a 1 microfarad 250 VAC capacitor across hour counter coils to stop counting while the contact was open. Even if your LED is in a DC circuit, it could still pick-up AC from wires close to its own wire. It would help to tell us the supply voltage to the pushbutton and LED lamp. Also if the lamp has an internal series ballast resistor or an external one. As has been commented, a resistor in parallel with the LED lamp may fix the problem. Have you measured the resistance of the LED lamps with an ohm meter {try both polarities!]? Comparing Carlo Gavazzi with Telemecanique may reveal that Telemecanique put a high value resistor in parallel with the LEDs.

Everything will depend on the existing back lit switch circuitry. 67model has a reasonable idea what might be happening but it is all pure speculation. A possible solution will be to add some parallel load to the lamp circuitry as an alternate path for the proposed capacitively coupled current that produces the dim light.

The only guaranteed solution will be to change the switch to a more appropriate device. Possibly a switch that changes color depending on state or that illuminates a separate ON and OFF lamp depending on status.

Spray a little black paint on the inside of the lens to dim it at night. It should still be visible during the day.

Cheers!

I have had the same problem with solid state relays, the relay would always be energized. The cause is probably caused by cable capacitance as was stated previously.

Our solution was to put a resistor in parallel with the LED.

Try maybe a 1 megohm resistor. If that works, then install a 499k or 500k resistor.

And then, if that works, how about a 249.5k or 250k resistor?

For sure, the pilot lamp is not of 380VDC but you will be having main supply source 380 VDC. This supply source is step down by using a step down transformer and this section of supply is called control voltage. Anywaz your green indication is for RUN and other light which you see glowing is power available indication and if you dont want this light then you can switch off main source. This is availabe on control panel itself. Whenever you want to start pump, you can switch on main and push the Start/Run button.

Are you perhaps switching neutral - not active?

_{I.e. the polarity feeding the load is wrong}

I suggest you connect a diode in reverse bias at the negative terminal of the LED.

Back feed is getting to the Light. Check your wiring Diagram, I have had this happen before and it was a bleed from a transformer to ground that was introduced to the indicator light in the starter. That was a pain to find.................but fun once I found it.

the pilot light/indicator is an of course incorporate LED as its light, but with associated step down resistor, diodes and rc components to accomodate 220vac/380vac power supply. perhaps for the polarity, i suppose not that relevant since AC volts is the supply. i tried using a series resistors as suggested but the "glow" still exist. tried also to install a "shunt" resistor of 10k across terminal L1 and L2, temporarily resolving the issue. however, when power is applied, resistor overheat despite increasing the wattage from 5 watts to 10watts. to remedy, i use interposing relay (2 NO contacts for each line of the pilot light), which i do not agree in terms of cost savings. (have to bought relay for this purpose only)

thanks guys

Glad you solved your problem with one of the suggestions. The figures you give, suggest the supply voltage is 380V - 10 kohm loses 14.5 watts at 380V, losses at 220V would be well under 10 watts you give for resistor rating. Have you considered an 0.33 microfarad capacitor to get 10 kohm at 50Hz without the high losses? A series resistor, say 150 ohms 3 watts, would be needed to protect driving contact from capacitor inrush.

thanks for your contribution. i will try this one and will keep you posted on the result.

thanks guys! cheers