Resistor braking
155
Resistor braking
What this chapter contains
This chapter describes how to select, protect and wire brake resistors.
Availability of brake choppers and resistors
Brake choppers are optionally available as built-in units, indicated in the type
description by +D150. External resistors are available on request from ABB.
When is resistor braking needed
Typically, a drive system is equipped with brake choppers and resistors if:
• high capacity braking is needed and the drive cannot be equipped with a
regenerative supply unit
• a backup for the regenerative supply unit is needed.
Operation principle
The energy generated by the motor during a fast deceleration of the drive typically
causes the voltage to rise in the drive module intermediate DC circuit. The chopper
connects the brake resistor to the intermediate DC circuit whenever the voltage in
the circuit exceeds its maximum limit. Energy consumption by the resistor losses
lowers the voltage until the resistor can be disconnected.
Planning the braking system
Selecting the brake circuit components
1. Calculate the maximum power
(P
max
) generated by the motor during braking.
2. Select a suitable drive and brake resistor combination for the application
according to the rating table on page
. Take also account of other factors in
the drive selection. The braking power must be greater than or equal to the
maximum power generated by the motor during braking:
3. Check the resistor selection. The energy generated by the motor during a 400-
second period must not exceed the resistor heat dissipation capacity
E
R
.
Note:
If the
E
R
value is not sufficient, it is possible to use a four-resistor assembly
in which two standard resistors are connected in parallel, two in series. The
E
R
value of the four-resistor assembly is four times the value specified for the
standard resistor.
P
br
>
P
max
Summary of Contents for ACS850-04 series
Page 1: ...ABB machinery drives Hardware manual ACS850 04 drive modules 160 to 560 kW 200 to 700 hp ...
Page 4: ......
Page 12: ...Table of contents 12 ...
Page 20: ...Safety instructions 20 ...
Page 26: ...Introduction to the manual 26 ...
Page 81: ...Installation 81 Assembly drawing frame G1 3AUA0000132078 ...
Page 82: ...Installation 82 Assembly drawing frame G2 3AUA0000132062 ...
Page 83: ...Installation 83 Assembly drawing air baffles 3AUA0000132062 ...
Page 92: ...Installation 92 3 6a 6b 5 4 8 4 8 6a 6b 7a 7b 7b ...
Page 112: ...Installation checklist 112 ...
Page 114: ...Start up 114 ...
Page 116: ...Fault tracing 116 ...
Page 140: ...Technical data 140 ...
Page 142: ...Dimension drawings 142 Frame G1 Drive module dimensions ...
Page 143: ...Dimension drawings 143 Frame G1 Drive module dimensions with optional cabling panels H381 ...
Page 144: ...Dimension drawings 144 ...
Page 145: ...Dimension drawings 145 Frame G1 Cabling panels H383 installed into a Rittal TS 8 cabinet ...
Page 146: ...Dimension drawings 146 Frame G2 Drive module dimensions ...
Page 147: ...Dimension drawings 147 Frame G2 Drive module dimensions with optional cabling panels H381 ...
Page 148: ...Dimension drawings 148 ...
Page 149: ...Dimension drawings 149 Frame G2 Cabling panels H383 installed into a Rittal TS 8 cabinet ...
Page 150: ...Dimension drawings 150 Frames G1 and G2 Bottom plate 3AUA0000082240 ...
Page 151: ...Dimension drawings 151 Frames G1 and G2 Air baffles 3AUA0000138986 ...
Page 152: ...Dimension drawings 152 ...
Page 162: ...du dt filters 162 ...
Page 164: ...3AUA0000081249 Rev C EN 2013 04 11 Contact us www abb com drives www abb com drivespartners ...