Technical data

March 2009
CA08102001E For more information visit: www.eaton.com
33-81
NEMA Contactors & Starters
33
Freedom
Technical Data and Specifications
Electrical Life — AC-3 and AC-4
Utilization Categories
Life Load Curves
Eaton’s Cutler-Hammer Freedom
Series NEMA contactors have been
designed and manufactured for supe-
rior life performance in any worldwide
application. All testing has been based
on requirements as found in NEMA and
UL standards and conducted by Eaton.
Actual application life may vary
depending on environmental condi-
tions and application duty cycle.
Utilization Categories
The International Electrotechnical
Commission (IEC) has developed
utilization categories for contactors
and auxiliary contacts. The IEC utiliza-
tion categories are used to define the
type of electrical load for estimating
electrical life, and do not imply the
devices are IEC rated.
AC-1 — Non-inductive or slightly
inductive loads, such as resistance
furnaces and heating.
AC-2 — Starting of slip-ring motors.
AC-3 — Squirrel cage motors; starting,
switching off motors during running.
AC-4 — Squirrel cage motors; starting,
plugging, inching or jogging.
Note: AC-3 tests are conducted at rated
device currents and AC-4 tests are con-
ducted at six times rated device currents.
All tests have been run at 460V, 60 Hz.
Contactor Choice
■ Decide what utilization category
your application is and choose the
appropriate curve.
■ Locate the intersection of the
life-load curve of the appropriate
contactor with the applications
operational current (Ie), as found on
the horizontal axis.
■ Read the estimated contact life
along the vertical axis in number of
operational cycles.
Figure 33-26. AC-3 and AC-4 Utilization Categories
NEMA AC-3 Load Life, Sizes 00 – 5, 480V 60 Hz
100,000,000
10,000,000
1,000,000
100,000
9
110
Break Amperes
100 1000
18 27 45 90 135 270
Size 00
Size 0 Size 1
Size 2 Size 3
Size 4 Size 5
Operations Operations
NEMA AC-4 Load Life, Sizes 00 – 5, 480V 60 Hz
100,000,000
Size 00 Size 0 Size 1 Size 2 Size 3 Size 4
Size 5
10,000,000
1,000,000
100,000
10,000
10854
110
Break Amperes
100 1000 10,000
153 270 540 822 1620