How do you size a magnetic contactor?
Table of Contents
How do you size a magnetic contactor?
There are 5 primary things to consider when determining how to size a contactor for your application:
- Full Load Amperage at Line Voltage. The first item to consider is the load, which is measured in amperes.
- Contactor Coil Voltage.
- IEC Utilization Categories.
- Reversing vs Non-Reversing Contactors.
- Auxiliary Contacts.
How do you choose a magnetic contactor for a motor?
3 Steps to selecting the right contactor for your motor application
- Step 1: Gather the right information from your motor’s nameplate.
- Step 2: Find the right manufacturer’s datasheet and selection guideline for the load type.
- Step 3: Make the selection.
What is A1 and A2 in magnetic 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.
What is the criteria to select the contactor?
You should select the suitable contactor according to the number of phases of the load. For example, if you want to control a 3 phase motor, you should use 3 pole contactor. If you want to disconnect the neutral, your choice should be 4 pole version.
How is motor contactor calculated?
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.
What is the difference between A1 and A2 in electrical circuit?
One side of the contactor coil (A2) is connected directly to one of the incoming power lines. The other side of the coil (A1) has two possible pathways to complete a connection to the other incoming power line.
Can I use a 40 amp contactor with a 30 amp?
Yes, the contact current rating is a maximum value. A 40 amp contactor can replace a 30 amp one. Yes, but make sure it’s not physically too big, so it fits in the space..
Can I replace a 30 amp contactor with a 40 amp contactor?
The contact current rating is the maximum value. A 30 Amp one can be replaced with a 40 Amp one. It fits in the space if it’s not too big.
What amp contactor do I need?
Size of Main Contactor = 100%x6 = 6 Amp….4. Size and Type of Contactor.
| Application | Contactor | Cap |
|---|---|---|
| Non-Inductive or Slightly Inductive ,Resistive Load | AC1 | 1.5 |
| Slip Ring Motor | AC2 | 4 |
| Squirrel Cage Motor | AC3 | 10 |
How do you calculate 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.
What are numbers 95 and 96 used for on the magnetic starter?
The contact 95-96 is used to control the load contactor. The overload relays have a setting scale in Amperes, which allows the direct adjusting of the relay without any additional calculation.
What is difference between AC1 and AC3 rating?
The difference between AC1 and AC3 contactors is AC1 contactors are used for general purpose resistive loads but AC3 contactors are used for high inductive, squirrel cage motor switching. The rating of AC3 is lower than AC1. Because AC3 switches high inrush currents.
