Technical data

33-14
For more information contact Cutler-Hammer at: www.ch.cutler-hammer.com/catalog CAT.201.01.T.E
January 2001
NEMA Contactors & Starters
33
Technical Data
Freedom Line
Vol. 2, Ref. No. [0030]
Electrical Life — AC-3 and AC-4
Utilization Categories
Life Load Curves
Cutler-Hammer’s Freedom Series
NEMA contactors have been designed
and manufactured for superior life
performance in any worldwide appli-
cation. All testing has been based on
requirements as found in NEMA and
UL standards and conducted by Cutler-
Hammer. Actual application life may
vary depending on environmental
conditions and application duty cycle.
Utilization Categories
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 33-3. 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
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