12
Resistor braking
Contents of this chapter
This chapter describes how to select, protect and wire brake choppers and resistors.
The chapter also contains technical data.
Operation principle and hardware description
The brake chopper handles the energy generated by a decelerating motor. The chopper
connects the brake resistor to the intermediate DC circuit whenever the voltage in the
circuit exceeds the limit defined by the control program. Energy consumption by the
resistor losses lowers the voltage until the resistor can be disconnected.
For frame R1…R3 internal brake choppers and resistors, see below. For R4…R9 external
brake choppers and resistors, see Resistor braking, frames R4…R9 (page 343).
Resistor braking, frames R1…R3
￭ Planning the braking system
Selecting the brake resistor
Frames R1…R3 have an built-in brake chopper as standard equipment. The brake
resistor is selected using the table and equations presented in this section.
1.
Determine the required maximum braking power P
Rmax
for the application. P
Rmax
must be smaller than P
BRmax
given in the table on page 338 for the used drive type.
2.
Calculate resistance R with Equation 1.
3.
Calculate energy E
Rpulse
with Equation 2.
Resistor braking 337
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