How do I choose a magnetic contactor?
As per above chart:
- Type of Contactor = AC7b.
- Size of Main Contactor = 100%X Full Load Current (Line).
- Size of Main Contactor = 100%x6 = 6 Amp.
- Making/Breaking Capacity of Contactor = Value above Chart x Full Load Current (Line).
- Making/Breaking Capacity of Contactor = 8×6 = 52 Amp.
How do you select a contactor?
When selecting a contactor, please make sure that the contactor’s rated current is specified for the AC-3 load type. Ensure that you are looking at the right table. You can see the rated current for the AC-3 load is lower than the rated current for the AC-1 load.
How do you use a magnetic contactor?
Magnetic contactors are a form of electrical relay found on most electrically powered motors. They act as a go-between for direct power sources, and high-load electrical motors in order to homogenize or balance out changes in electrical frequency which may come from a power supply as well as to act as a safeguard.
What are the different types of contactors?
There are different types of contacts in a contactor namely, contact springs, auxiliary contacts, and power contacts. Each type of contact has an individual role to play.
What are the three current ratings found on a contactor?
Contactors are rated by designed load current per contact (pole), maximum fault withstand current, duty cycle, design life expectancy, voltage, and coil voltage.
How many amps 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 is the difference between ac1 and ac3 duty contactor?
AC-1 – This category applies to all AC loads where the power factor is more than 0.95. … AC-3 – This category applies to squirrel cage motors with breaking during normal running of the motor. On closing, the contactor makes the inrush current, which is about 5 to 7 times the rated full load current of the motor.
What is NO and NC In Contactor?
Relays and contactors have two types of contacts, each suited for different applications: Normally open (NO) contacts allow current when the relay or contactor is energized. … Normally closed (NC) contacts allow current through when the relay or contactor is not energized.
What are the parts of magnetic contactor?
A magnetic contactor has two incoming circuits which include the main circuit to power the load and an auxiliary circuit to operate the contactor itself. The auxiliary circuit connects to an induction coil, and when current flows through the circuit, the coil generates a magnetic field.
Why contactors are used?
Why are Contactors Used? Contactors are used for high power applications. They allow a lower voltage and current to switch a much higher power circuit, so they are generally larger and more heavy-duty than control relays, enabling them to switch higher power loads on and off for many thousands of cycles (Figure 1).
How many ohms Should a coil read?
Most ignition coils should have a primary resistance falling somewhere between 0.4 and 2 ohms; however, refer to your manufacturer’s specifications for the correct reading. If a reading of zero is displayed, that signifies that the ignition coil has shorted internally in the primary windings and needs to be replaced.
What’s the difference between a relay and a contactor?
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.