What is Utilization category of isolator?
A range of switch disconnectors (isolators) are available for use on lower current ratings from 20A to 125A, these switches are rated at AC-22 and provide a cost effective alternative to the fuse combination switch especially where the utilisation category AC-23 is not required. ie; mixed resistive and inductive loads.
What is Utilization category of circuit breaker?
The standard defines two utilisation categories, A and B, depending on circuit breaker discrimination with upstream breakers under short-circuit conditions. Category A. Circuit breakers not specifically designed for discrimination applications. Category B.
What is AC3 duty utilization category?
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 is Type 1 and Type 2 coordination starters?
Type 1 and Type 2 coordination was IEC developed criteria of short-circuit performance for starters and contractors. It defines levels of the motor controller’s protection that follows a short-circuit fault.
How are AC-1 and AC-3 utilization categories different?
It can be noticed that operational current ratings are different for utilization categories AC-1 and AC-3, also for different voltages. All AC loads having power factor higher than 0.95 are listed under AC-1 utilization category. Example: resistive load, heating, distribution. These loads have much lower starting current or inrush current.
Which is an example of an AC 1 load?
All AC loads having power factor higher than 0.95 are listed under AC-1 utilization category. Example: resistive load, heating, distribution. These loads have much lower starting current or inrush current. The arc formed while opening the contacts are minimal and can be easily extinguished.
What are the utilisation categories of the IEC?
In order to assist with selection of switchgear devices, the International Electrotechnical Commission (IEC) defined several utilisation categories.
What are the different types of AC duty contactors?
AC duty (Alternating Current) for Contactors: AC-1: Such duty contactors are used in resistive loads such as heaters and electrical furnace. Non-inductive or slightly inductive loads are included which means the power factor of the load lie between 0.95 to 1.
