Automation Canada Machine Safety Issue May 2021 - 30

UNDERSTANDING THE OPTIONS FOR
MOTOR DISCONNECT SWITCHES
Motor disconnects are more than simple on-off devices to satisfy lockout-tagout requirements. They
have become an integral part of the motor control circuit as disconnects increasingly offer control
functions, such as auxiliary contact interface, added selector switches and push buttons. Disconnects can
be metal or nonmetal, as well as fusible or non-fusible. They can have different pole arrangements and
environmental ratings, and some integrate innovative curved profiles
to eliminate standing water and minimize contaminant buildup in food processing and other cleanroom
operating environments. You can even pack multiple disconnects into one enclosure, saving space and
cost.
The following paper discusses the specification steps you should keep in mind when selecting a motor
disconnect, as well as the various electrical, installation and enclosure options that will determine how
your disconnect functions in its operating environment.
SPECIFYING YOUR DISCONNECT
With all the different motor disconnects on the market, the best choice for your application isn't always
obvious. But if you follow a few simple specification steps, you'll end up with the right disconnect switch
every time.
Evaluate the operating environment.While it's good to pay attention to the electrical characteristics
of a motor disconnect, it's just as important to carefully evaluate the disconnect's operating
environment-a step that is oſten overlooked. The operating environment will determine what type of
housing material will work best in your plant or on your shop floor.
High-quality motor disconnect switches are available in both metallic and non-metallic. MENNEKES
products use UL Listed metallic and non-metallic enclosures, both with a NEMA 4X rating, so they offer
watertight protection
for harsh environments. Many NEMA 4X enclosures can withstand challenging operating conditions,
including those with corrosive chemical exposures and caustic cleaning substances. If both metallic and
non-metallic can meet the same NEMA rating, typically the manufacturing environment will make the
choice clear.
Where stainless steel shines. Stainless steel and other metallic enclosures are increasingly favored in
areas with the potential for direct food contact. Food and beverage manufacturers prefer metallic
enclosures in high traffic areas since metal detection systems can pick up foreign matter if there is any
MENNEKES® 277 Fairfield Road, Fairfield, NJ 07004
T: 800-882-7584
F: 973-882-5585
E: info@MENNEKES.com www.MENNEKES.com
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Automation Canada Machine Safety Issue May 2021

Table of Contents for the Digital Edition of Automation Canada Machine Safety Issue May 2021