How do you size a magnetic contactor?
How do you size 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 is contactor size calculated?
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 many circuits can a contactor control?
Lighting contactors can also be of the multi-pole type, rated to make and break many 20/30/40 amp branch circuit loads (generally 4 – 20 circuits). Multiple contactors can be wired together for group operation. Contactors are therefore a good method of controlling blocks of similar loads.
How do you choose a magnetic contactor for a motor?
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.
Why DC motors of medium sizes are fitted with starters?
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. This gives a starting current (Ia) of 550 amps, which can be more than ten times the rated current, and high enough to damage the internal motor circuit.
How do you determine overload size?
The overloads are determined using 125% of the FLA, 7A x 1.25 = 8.75A. The maximum allowable size for the overloads is 9.8A. The overloads can be sized at 140% of the FLA if the overloads trip at rated load or will not allow the motor to start, 7A x 1.4 = 9.8A.
How do you select a magnetic contactor?
What is the difference between a magnetic starter and a contactor?
Contactors can be used as a magnetic starter. A magnetic starter is a device designed to provide power to electric motors. It includes a contactor as an essential component, while also providing power-cutoff, under-voltage, and overload protection.
What is AC1 and AC3 rating of contactor?
The difference between AC1 and AC3 contactors is AC1 contactor is used for less inductive loads such as resistive loads (the power factor of the load is near about 1) but AC3 duty contactors are used for high inductive, squirrel cage motors which will be off during the motor is running condition.
What voltage should a contactor coil be set at?
Contactor Coil Voltage You should next confirm the control voltage to be used to power the contactor. This can be the same as the line voltage, however often a lower voltage is selected for the contactor for safety purposes. Generally, coil voltages are 250V or below.
What are the different types of AC contactors?
Contact can be divided into three types of point contact, line contact and surface contact by contact conditions, the contract of AC contactor is generally double breakpoints bridge contact. According to the make-break capacity, contract of AC contactor is mainly divided into main contact and auxiliary contact.
What happens when the AC contactor disconnects circuits with large current?
When the AC contactor disconnects circuits with large current or high voltage, a strong arc will be produced between the movable and static contacts.
How do I choose the right contactor size?
If a motor will be jogged or have frequent stop/starts, then it should be accounted for by choosing a slightly larger contactor. It’s not just a question of what type of device you are powering, but also how it may be used. Springer Controls sizes our contactors for 10 million operations to ensure long life.
