What could voltage across a closed contact in a 24V control circuit indicate?

When voltage is present across a closed contact in a 24V control circuit, it typically suggests that there is an issue with the contacts themselves, such as being pitted or dirty. This can happen due to wear over time or when electrical arcs occur as contacts open and close, which can lead to carbon buildup and surface degradation.

In ideal conditions, when the contacts are functioning correctly, you would expect to see a low or negligible voltage drop across them. A significant voltage reading across closed contacts indicates that there might be resistance caused by poor contact quality, which can hinder the reliable operation of the control circuit.

While proper functioning can indicate that there’s no short circuit or open circuit, the presence of a voltage across closed contacts leans towards a problem rather than optimal operation. Proper functioning would mean that the contacts are allowing current to flow without significant resistance, thereby not showing a voltage drop. Thus, the reading of voltage suggests issues with contact integrity rather than good operation.