Motortronics
Page 5
1.4 Applications
The ABC Series electronic brake is ideal for machine and process equipment control applications for efficiency,
increased safety, and reduced equipment maintenance costs. Among the benefits:
Efficiency is improved because you no longer have to wait through long coast-to-stop times for blade changes,
batch loading, or maintenance shutdowns. Productive time increases as overall operating costs decrease
because the load stops more quickly. The ABC Series eliminates the common practice of jamming the load to a
stop which seriously reduces the life and effectiveness of saw blades, molding heads, and knives.
Increase Safety by eliminating the need to "jam-stop" equipment. This will prevent any personnel injuries
caused by kickbacks and broken blades. Use the ABC Series in conjunction with safety inter- lock devices to
stop the motor as quickly as possible, reducing the risk of contact with dangerous rotating elements of
machinery. Prevent premature wear or component failure and eliminate the need for hasty repairs that can put
maintenance personnel in potentially dangerous situations. ABC Series brakes can be used as part of a system
to facilitate O SHA General Industry Standards (29 CFR1910 Subpart O) requiring that workers not be
exposed to hazardous moving parts. They can also be utilized to satisfy braking requirements of the British
Columbia Workers Compensation Amendment Act (Book 3 Part 27.42) for rotating knife machinery such
as planers, chippers, and hogs.
Reduce maintenance costs by using the ABC Series. Eliminate the need to plug-reverse a load and reduce
the associated damage to gear boxes and other power train components. The ABC Series can be used to stop
or slow down the load in one direction before reversing to the other. On machines where mechanical brakes are
used to stop or hold a load, use the ABC Series to stop it first, then set the mechanical brake as a "parking
brake". This eliminates the normal wear and tear to the brake pads or shoes. On loads such as vibrating
feeders, screens, or separators, damage from mechanical harmonics that occur during coast-down can be
eliminated by using an ABC Series. It allows the motor/load to quickly pass through any dangerous speeds and
come to a stop.
1.5 Where Mechanical Brakes should be used
Power loss during braking - The ABC Series, like all DC injection brakes, requires power to be applied during
the braking cycle. If the incoming line power is lost from the utility, an upstream circuit protective device trips, or
an emergency shutdown routine is initiated, no braking will take place. If braking is still necessary for safety
reasons (even in the event of a power failure), consider using mechanical brakes as a backup device. Under
normal operation conditions, the ABC Series stops the load and the mechanical brake holds it.
Holding the load after it comes to a stop - All DC injection brakes inherently lose braking torque when the
motor comes to a complete stop and therefore
CANNOT BE USED AS HOLDING BRAKE
. If braking must be
applied continuously while the load is at rest, mechanical "Parking Brakes" are required. The ABC Series
includes a Mechanical Brake Release Relay to facilitate proper coordination of the mechanical brake in these
applications.
Stop times shorter than start times - Like all DC injection brakes, the ABC Series waits for the residual motor
energy to dissipate from the windings before DC current can be applied (otherwise damage to the brake or
circuit devices may occur). The length of this "wait state" depends on the motor's residual magnetism and the
motor frame size, but can be as much as 5 seconds. This, combined with the limits on braking torque, makes DC
injection braking ineffective if braking time must be shorter than the starting time (Across-the-Line).
WARNING!
DC Injection brakes cannot be used for holding a load after it comes to a stop. The ABC Series includes a
Mechanical Brake Release Relay that can be used to coordinate the operation of a mechanical brake for
use in these applications.
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
