Electric Motor Control Basics - Book - Page 59
Applying Motor Control in a Wastewater Application
Types of Motor Controls used with Water and Wastewater Pumps
1. Contactor:
Contactors are components designed to switch on and off heavy loads in pump
motors. These components feature main contacts (poles), auxiliary contacts,
and an operating coil. They energize the contactor to switch on and off the main
contacts. Auxiliary contacts are designed for controlling and signaling various
circuit applications, whereas main contacts are the current carrying parts of these
contactors.
Typically these contactors feature 3-pole electrically operated switches, which take
less space when installed inside electrical enclosures. The motors used in water
treatment and wastewater treatment pumps are known to draw more energy at any
voltage. The possibility of electric shock increases at high voltage and may cause
heavy damage. However, AC and DC contactors are safe to use while starting the
motor, as there is no current flow between the circuit powering a contactor and the
circuit being switched.
The contactors are mounted so they do not touch the circuit that is being switched.
Because these contactors use less power than the main switching circuit, they help
reduce power consumption. Advanced motor contactors feature compact designs,
which further help reduce the footprint of the device and its power consumption.
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
59
