IMO SD1 Series - Braking Resistors; Selecting Braking Resistors

SD1 Series Inverters Optional Peripheral Accessories
-160-
C.7 Braking Resistors
C.7.1 selecting braking resistors
It is appropriate to use braking resistor or braking unit when the motor brakes sharply or the
motor is driven by a high inertia load. The motor will become a generator if its actual rotating
speed is higher than the corresponding speed of the reference frequency. As a result, the
inertial energy of the motor and load return to the inverter to charge the capacitors in the main
DC circuit. When the voltage increases to the limit, damage may occur to the inverter. It is
necessary to apply braking unit/resistor to avoid this accident happens.

Only qualified electricians are allowed to design, install, commission, and
operate on the inverter.
 Follow the instructions in "warning" during working. Physical injury or
death or serious property may occur.
 Only qualified electricians are allowed to wire. Damage to the inverter or
brake options and part may occur. Carefully read the instructions of
braking resistors or units before connecting them to the inverter.
 Do not connect the braking resistor to other terminals except for PB and
(-). Do not connect the braking unit to other terminals except for (+) and (-).
Damage to the inverter or braking circuit or fire may occur.
 Connect the braking resistor or braking unit to the inverter according to the
diagram. Incorrect wiring may cause damage to the inverter or other
devices.
SD1 series inverters have internal braking units.
Model
Type of
braking
unit
Braking
resistor at
100% of
braking
torque (Ω)
Consumed power of the braking
resistor (kW)
Min.
braking
resistor
(Ω)
10%
braking
50%
braking
80%
braking
SD1-2.5A-21
Built-in
braking unit
361
0.06
0.30
0.48
42
SD1-4.2A-21
192
0.11
0.56
0.90
42
SD1-7.5A-21
96
0.23
1.10
1.80
30
SD1-10A-21
65
0.33
1.70
2.64
21
SD1-2.5A-23
361
0.06
0.3
0.48
131
SD1-4.2A-23
192
0.11
0.56
0.9
93
SD1-7.5A-23
96
0.23
1.1
1.8
44
SD1-10A-23
65
0.33
1.7
2.64
44
SD1-16A-23
36
0.6
3
4.8
33
SD1-20A-23
26
0.75
4.13
6.6
25
SD1-30A-23
19
1.13
5.63
9
13