How to measure relay with multimeter

The relay consists of coil and contact group, which need to be measured separately to judge whether the relay is damaged.

Measuring method of coil resistance:

Use the ohmmeter, put the multimeter on a suitable electric block, and connect two probes to the lead-out pins of the relay coil at will for measurement.

Comparing the detection result with the nominal value to judge whether there is an open circuit phenomenon in the coil; If the resistance value is obviously small, the coil has a local short circuit fault; If the resistance value is zero, the coil is short-circuited; If the resistance value is infinite, the coil is open.

Measuring method of contact resistance:

Use the100Ω electrical block of an ohmmeter to measure the resistance between normally closed contacts, which is usually displayed as several tenths of ohms. If the resistance value is infinite, it means that the two tested contacts are disconnected.

Measure the resistance value of normally open contacts, usually the resistance value is infinite. If the displayed resistance value is small, it means that the two tested contacts are closed.

Extended data:

There are three basic forms of relay contacts:

1, when the moving (normally open) (H type) coil is not energized, the two contacts are disconnected, and when energized, the two contacts are closed. Represented by the combined pinyin prefix "h".

2. When the dynamically disconnected (normally closed) (D-type) coil is not energized, the two contacts are closed, and when energized, the two contacts are disconnected. It is represented by the phonetic prefix "d" of hyphen.

3, conversion type (Z type) This is the contact group type. The contact group * * * has three contacts, namely the moving contact in the middle and the static contact at the top and bottom. When the coil is not energized, the moving contact and one stationary contact are disconnected and the other is closed. After the coil is energized, the moving contact moves, so that the original disconnected contact is closed, and the original closed contact is in the disconnected state, thus achieving the purpose of conversion.

Such a contact group is called a transfer contact. It is represented by the phonetic prefix "z" of the word "Zhuan".

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