How do you size an electrical contactor?

As per above chart:

1. Type of Contactor = AC7b.
2. Size of Main Contactor = 100%X Full Load Current (Line).
3. Size of Main Contactor = 100%x6 = 6 Amp.
4. Making/Breaking Capacity of Contactor = Value above Chart x Full Load Current (Line).
5. Making/Breaking Capacity of Contactor = 8×6 = 52 Amp.

What is contactor size?

NEMA contactors for low-voltage motors (less than 1,000 volts) are rated according to NEMA size, which gives a maximum continuous current rating and a rating by horsepower for attached induction motors. NEMA standard contactor sizes are designated 00, 0, 1, 2, 3 to 9.

What is 24V contactor?

Contactors are used for all kinds of electrical and automated applications, including the control of lighting, heating and electric motors. An example of a contactor is a 24V electromagnetic coil used to control a 230V motor switch circuit.

Can you oversize a contactor?

A contactor is a glorified switch and the ratings are for its own function. You want to avoid under-sizing a contactor, but you can oversize.

What are 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 ohms should a contactor coil have?

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.

Can a contactor cause a short?

Yes….. very possible and quite common. At 2 ohms that contactors coil is shorted.

Which side of contactor is common?

Different Types of Contactors – Single Pole, Double Pole, 3 Pole. A single pole contactor only has to connect one wire for power. The other leg is just the neutral/common and is always in the circuit.

What does AC3 mean on a contactor?

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. On opening, the contactor breaks the rated full load current of the motor.

What are the types of Schneider Electric contactors?

Class 9991 Types SCW20 and SDW20 are designed for contactors only; reset closing plates are not required. SAO, SBO, SCO 00, 0, 1 SCW20 SCW11 2 SCA11 2 SCH2

How big is a heavy duty IEC contactor?

Heavy Duty IEC starters in this guide are sized for NEMA equivalent horsepower sizes. The NEMA size equivalent contactors have been increased by one or more sizes over the standard duty contactor selections in order to meet the single and three phase NEMA HP ratings. The table below shows the oversizing used at each horsepower.

When do you use class 8502 AC contactors?

© 1998 Square D All Rights Reserved 2 5/98 AC MAGNETIC CONTACTORS CLASS 8502 General Information Class 8502 Type S magnetic contactors are used to switch heating loads, capacitors, transformers, and electric motors where overload protection is separately provided. Class 8502 contactors are available in NEMA Sizes 00-7. Type S contactors

What kind of contactors do capacitors use?

Class 8502 Type S magnetic contactors are used to switch heating loads, capacitors, transformers, and electric motors where overload protection is separately provided. Class 8502 contactors are available in NEMA Sizes 00-7. Type S contactors are designed for operation at 600 Volts, AC 50-60 Hertz. Holding Circuit Contact