User Manual

Application Data
Appendix D
D-3
Bulletin 1333 The Bulletin 1333 Adjustable Frequency Drive has the ability to let a
Heavy Duty Dynamic Braking connected motor generate braking torque. This ability however, is limited
to approximately 20% of the drive rated braking torque. The braking
torque can be increased by adding one or more Bulletin 1333 heavy duty
dynamic braking kits to the drive. Typically the braking torque can be
increased to 100% for 20 seconds at a duty cycle of 20%.
The following evaluation can help determine if heavy duty dynamic
braking may be required for your application.
Brake Specifications Braking Torque: 100% Torque for 20 Seconds (typical)
Duty Cycle: 20% (typical)
Input Power: Power from Drive DC Bus
Temperature: –10 to + 50°C (+14 to +122°F).
Humidity: 5 to 95% Non-Condensing
Atmosphere: No Corrosive Gas or Non-Hazardous Dust
Humidity: 3,300 Feet (1,000 Meters) Maximum without Derating
Enclosure Type: NEMA Type 1 (IP20)
How to Select a Brake To begin selection, the following application information must be obtained.
The nameplate horsepower of the motor HP.
The nameplate base speed of the motor N in RPM.
t
2
N
2
RPM
N
1
RPM
t
1
The speed profile of the motor
where: N
1
= The motor’s minimum speed in RPM.
N
2
= The motor’s maximum speed in RPM.
t
1
= The motor’s cycle time in seconds.
t
2
= The motor’s decel time in seconds.
Motor
Inertia
wk
2
M
Gear
Ratio
GR
Load
Inertia
wk
2
L
Input
RPM
Output
RPM
The motor inertia,
the nameplate gear reduction
ratio, and the load inertia.