Electric Motor Control Basics - Book - Page 64
Applying Motor Control in a Wastewater Application
Tips when Selecting Motor Controls for use with Water and
Wastewater Pumps
Industrial Control
Basics:
Part 1, Contactors
Contactors
Industrial Control
Basics: Part 2,
Overload Relays
These devices are often confused with relays, however, the main difference is
contactors can easily switch higher currents and voltages, whereas the relay is used for
lower current applications. Keep the following in mind when selecting contactors for
your motors:
• Decide what amount of current, FLA - Full Load Amperage will be required to power
your pump motor.
• Select the coil voltage for AC or DC operation based on your motor horsepower,
input voltage, and single or 3-phase. Coils are mainly offered in control voltages
such as 24VAC, 230VAC, 400VAC, 24VDC, and so on.
• Selecting a contactor with an IEC Utilization Category of AC-3 is typical for pump
applications requiring starting and switching off motors during run time.
• Determine if your pump operation will require reversing of the direction, in which
case a reversing contactor will be required.
• Choose the auxiliary contact based on normally open or normally closed
configurations.
• In addition to the above considerations, it is important to concentrate on ambient
and environment temperatures, necessity of latching, interlocking, enclosures,
overload, timers or coil surge suppressors.
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
64
