What should a contactor coil read?
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 a coil in a contactor?
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 is a magnetic contactor used for?
Magnetic contactors are used in the electric motors to balance the change in frequency of the motor or the state of the motor which can be termed as the switching of the motor from ON and OFF state.
How do I know if my contactor coil is bad?
Check ohms. Touch each lead to the coil connectors and look for a reading between 10 to 100 ohms. If you do not get this reading, you have a bad coil. If your contactor or coil is malfunctioning, you can purchase a new one separately to repair your AC unit.
Why do contactor coils burn out?
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”.
What do the numbers on a contactor mean?
These auxiliary contacts (also called control contacts) each have an order number and a function number. The first number is used consecutively (order number) and the second number specifies the type of contact (function number).
How much current does a contactor coil draw?
The inrush current for a size 2 contactor with a 120 volt coil is 1.8 A and the seal-in current for the same coil is 0.25 A.
What causes a contactor coil failure?
How do you calculate contactor coil current?
- First, the type of the AC contactor for the motor generally adopts the ac-3 series.
- Then, the working current of the motor is estimated: I=5.5*2=11A.
- At last, the working current of the AC contactor can be about: 11*1.5=16.5A.
- We can choose 18a, which is slightly larger, as the working current.
How do I select a contactor?
The followings are the selection parameters of a contactor.
- Number of poles. Power contactors have 3 poles or 4 poles versions.
- Utilization category.
- Current and power.
- Coil voltage.
- Rated operating voltage (Ue), Insulation voltage (Ui), Impulse voltage (Uimp)
- Number of auxiliary contacts.
- Size.
- Mounting types and positions.
What is a 237 contactor used for?
NEMA Magnetic Contactors 237 products Heavy-duty magnetic contactors prevent expensive damage to industrial machinery. The correct contactor type and capacity bridges the gap between direct power sources and high-load electrical lights, heaters and motors.
How do heavy-duty magnetic contactors work?
Heavy-duty magnetic contactors prevent expensive damage to industrial machinery. The correct contactor type and capacity bridges the gap between direct power sources and high-load electrical lights, heaters and motors. These contactors balance changes in electrical frequency and cut the current in the event of a malfunction or overload. View More
What is the purpose of contactors?
The correct contactor type and capacity bridges the gap between direct power sources and high-load electrical lights, heaters and motors. These contactors balance changes in electrical frequency and cut the current in the event of a malfunction or overload. View More View All