It’s a simple question: do the normally open or normally closed contacts of a relay refer to the state when there is power or when there is no power?

Normally open and normally closed refer to the condition when the coil is not powered.

The normally open and normally closed contacts have nothing to do with whether the coil is powered or not, right? However, the normally open contacts close when powered, while the normally closed contacts open when powered. Last edited by The wind is gentle on 2009-3-11 19:17]

Hehe, saying that he had gotten confused himself

It should refer to the state where the coil is not charged

This should be determined through consultation between the instrumentation team and the electrical team. For example, if the electrical system requires normally closed contacts, then the contacts provided by the instrumentation team to the electrical team should be closed under normal conditions. There is one type of contact, which is the normally closed contact defined by the relay when it is not powered; and another type is the normally open contact defined by the relay when it is powered (in this case, the normally open contact while the relay is powered corresponds to the normally closed contact required by the electrical team). Sometimes, safety requirements related to accidents dictate that solenoids must be powered under normal conditions; in such cases, the normally open and normally closed contacts are not those defined when the solenoid is not powered. Therefore, to determine whether the contacts to be provided to the electrical system or solenoids should be normally open or normally closed, it is first necessary to decide whether the relay is normally powered or not. If the relay is normally powered, then the normally open contact is actually the relay’s normally closed contact; if the relay is normally not powered, then the normally open contact is indeed the relay’s normally open contact. Last edited by 158432543 on 2009-3-11 20:38.]

Normal open – NO (normal open): It is in the open state under normal circumstances, that is, it is disconnected when the coil is not powered. Normal closed – NC (normal close): It is usually in a closed state, that is, it remains closed when the coil is not powered.

In the circuit diagram, all states are in a power-off state

It refers to the state of the contacts when the coil is not excited.

Judge when the coil is not powered

Judge when the coil is not powered

Normally open and normally closed refer to the state of the contacts when the coil is not energized.

It’s described in great detail; it’s a good post.

Normally open: It remains open under normal conditions, that is, without power (electricity) it stays open; it closes when powered. Conversely, for normally closed contacts, they open when energized.

Of course, it refers to the situation when the coil is not charged

Many experts upstairs are overcomplicating things. To put it simply, it’s due to a power outage

In the circuit diagram, all states are in a power-off state

It’s a simple question: the normally open and normally closed contacts of a relay refer to the state of its contacts when it is not powered; there’s no need to compare them with any other reference points.