Electric Motor Control Basics - Book - Page 78
NEMA vs IEC Motor Controls
3. Type 2 Coordination
This is an IEC standard that applies to NEMA products as well. It’s afforded by the
use of a contactor or starter. The protection type requires the starter to be reusable
after short-circuit conditions. The IEC standards allow no significant changes in the
operating time-current features of the overload relay.
Since this is a coordinated protection standard, it applies to both NEMA and IEC.
However, NEMA has a greater selection of short-circuit protective devices. The
selection of fuses with IEC-style products is limited.
It’s also worth noting that IEC products are more disposable than serviceable. Most of
them below 100A can’t be serviced; they are required to be removed from a DIN rail,
for replacement with a new component.
Self-protected starters are the representation of a new category of combination
starters. This kind of starter has a contactor, overload relay, and short-circuit
protection. They also undergo a unique testing procedure that goes beyond the
conventional combination of motor controls.
4. Training
One of the biggest differences between IEC and NEMA products is training. The design
of IEC products is more application-specific. The products also require a higher level of
knowledge in the selection process.
You may not need intensive training to be able to select an IEC product, but the training
has to be very specific. It calls for more time and knowledge upfront, to match the
Industrial Control
Basics:
Part 1, Contactors
Industrial Control
Basics: Part 2,
Overload Relays
Industrial Control
Basics: Part 3,
Starters
The Benefits of Type E/F
Motor Protection
Circuit Breakers
Basic Pump Control:
Three Phase DOL Starter
Control of an Electric Pump
Applying Motor Control
in a Wastewater
Application
NEMA vs IEC Motor
Controls
Understanding
IP Ratings
78
