Electric Motor Control Basics - Book - Page 67
Applying Motor Control in a Wastewater Application
• Digested Sludge Pumps: Contaminated sludge is treated in wastewater treatment
plants before being released into water bodies. The sludge contains solids which
may block the pipeline, so special pumps are used for the purpose. Sometimes,
sludge choppers are integrated into the pumps, or submersible centrifugal pumps
are used for pumping fluids having high sludge content.
• Submersible Pumps: As their name suggests, these pumps are completely
submerged in the liquid. These pumps are used to drain the slurry or sewage and
are mostly placed under the sewage or wastewater treatment plants. Their
operation is controlled using advanced motors.
Applicable Standards and Compliances
All motor controls referenced in this document are designed in accordance with
standards published by NEMA (National Electrical Manufacturers Association) or IEC
(International Electrotechnical Commission).
NEMA is primarily a North American Standard, whereas IEC is a global standard.
Nema Rating
The NEMA ratings of a starter depend largely on the maximum horsepower ratings
given in the National Electrical Manufacturers Association ISCS2 standard. The
selection of NEMA starters is done on the basis of their NEMA size, which varies from
Size 00 to Size 9.
The NEMA starter, at its stated rating, can be used for a wide range of applications,
ranging from simple on and off applications to plugging and jogging applications,
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
67
