Voltage isolation of a relay coil, from an ungrounded floating 125 VDC control circui

[hazzjazz]

If a 125 VDC relay coil is powered from an ungrounded, floating, 125 VDC supply, what voltage level could typically be present on the coil, from the negative side of the circuit, when measured from ground, with the positive side of the 125 VDC circuit open and isolated from ground?

 

[templdl]

If a 125 VDC relay coil is powered from an ungrounded, floating, 125 VDC supply, what voltage level could typically be present on the coil, from the negative side of the circuit, when measured from ground, with the positive side of the 125 VDC circuit open and isolated from ground?

Didn't you say the 125vdc supply is ungrouded?

 

[gar]

151013-1944 EDT

hazzjazz:

I really don't know what is your question. But I will give some comments.

To measure a voltage you have to define two points between which you want the voltage measurement.

You have a simple series circuit consisting of a voltage source (could be a battery), likely some sort of switching element (could be a simple toggle switch), and a relay coil. This circuit is insulated from anything else because you said it was isolated.

Next suppose there is a very conductive earth spaced 4 ft below your circuit. At this point in time we have no way to define the voltage of your circuit relative to earth. Is there any voltage difference between the circuit and earth? Could be anywhere between 0 and some very large value like +/-1,000,000 V, or more. Coulds AC or DC and of any waveform.

Can you clarify what is your quesrion?

.