What is the proper procedure for checking the coil of a contactor or relay?

What is the proper procedure for checking the coil of a contactor or relay? The coil of a contactor or relay needs to be disassembled because the contacts are usually hidden. Once the contacts are visible, use the leads of an ohmmeter to measure across the coil by touching both contacts.

How do you check a contactor coil?

How do you troubleshoot a contactor coil?

Touch each lead to the coils connectors like reading the voltage, but with the meter in the ohms position. The meter should read from 10 to 100 ohms. If the meter does not, the coil is bad and must be replaced.

What is contactor coil?

What is a contactor coil? The contactor coil is an electrical passive device that has two terminals. When a control voltage is applied to its A1-A2 terminals it enables the main contacts of a contactor to change their position.

What causes a contactor coil failure?

By far the most common cause of contactor coil failure is, surprisingly to many, undervoltage. There may be sufficient voltage to pull the contactor in, but not enough to keep the coil armature formers firmly "sealed".

HOW TO TEST A CONTACTOR

What is the difference between a contactor and a relay?

A contactor joins 2 poles together, without a common circuit between them, while a relay has a common contact that connects to a neutral position. Additionally, contactors are commonly rated for up to 1000V, while relays are usually rated to only 250V.

How do you know if a contactor is bad?

A bad AC contactor can be identified by physical signs of deterioration, also known as pitting. Pitting occurs when the contactor has encountered extreme voltage and heat. A pitted contactor tends to stick, causing a continuous flow of electricity to the unit.

How does an AC contactor coil work?

The working principle structure of the AC contactor is shown in the figure below. When the coil is energized, the iron core is magnetized, attracting the armature to move downward, making the normally closed contact open and the normally open contact closed. When the coil is de-energized, the magnetic force disappears.

What causes contactor to spark?

the spark could be coming from high amps or something else. seems like you may have a few problems if you need to manually push in the contactor.

What causes arcing in a contactor?

Inadvertent synchronization of the contacts to line frequency can be caused by, but is not limited to, the following scenarios: Microcontrollers synchronized to power supply frequency. Thyristors synchronized to power supply frequency. Insufficient filtering of the DC power supply which drives the coil.

What is A1 and A2 on a contactor?

What Do A1 and A2 Mean on a Contactor? A1 and A2 on a contactor typically refer to either end of the electromagnetic coil assembly. Most contactor manufacturers use A1 and A2 to designate the two terminals connecting electrical power to the contactor's magnetic coil.

How do you tell if a contactor is shorted?

A shorted contactor has a resistance reading of zero. A small measurable resistance usually indicates a good coil. (If you have a good contactor measure it for your reference). The contacts must be in good enough condition to pass the voltage on to the load.

What is contactor relay?

A contactor is a special type of relay used for switching an electrical circuit on or off. They are most commonly used with electric motors and lighting applications.

What is the coil voltage of a relay?

The Rated Coil Voltage of a relay is the voltage that the relay is supposed to receive in order to be energized. This is the voltage that the relay ideally should receive when you energize it.