Dc Braking (Db) Settings; Normal Dc Braking Performance; Dc Braking - Frequency Detection - Omron 3G3MX2 User Manual

"A" Group: Standard Functions
3-5-5

DC Braking (DB) Settings

FW
F-SET
A052
F-OUT
Eample 1: Step change in F-SET
!Caution Be careful to avoid specifying to long braking time or to high carrier frequency

Normal DC braking performance

– The DC braking feature can pro-
vide additional stopping torque
when compared to a normal decel-
eration to a stop. DC braking is
particularly useful at low speeds
when normal deceleration torque
is minimal.

When you set
RV signal) turns OFF, the inverter injects a DC voltage into the motor windings
during deceleration below a frequency you can specify (
The braking power (
ally specify a wait time before DC braking (
free run.
DC Braking - Frequency Detection – You can instead set DC braking to
operate during RUN mode only, by setting
this case DC braking operates when the output frequency comes down to the
one you specified in
graphs figures below.
External DB and Internal DC braking are invalid during the frequency detec-
tion mode.
ON
DB
Example 1, (above left) shows the performance with
changing frequency reference. In this case, when the reference goes to 0, the
inverter immediately starts DC braking because the set point drops below the
value specified in
There will be no DC braking at next downward transition because the FW
input is OFF.
Example 2, (above right) shows a gradually changing frequency reference, for
example by analog input. In this case, there will be a DC braking period at
starting because the frequency set point is lower than the value specified in

.
that can cause motor overheating. If you use DC braking, we recommend
using a motor with a built-in thermistor, and wiring it to the inverter's thermis-
tor input (see 4-5-8 Thermistor Thermal Protection on page 211). Also refer to
the motor manufacturer's specifications for duty-cycle recommendations dur-
ing DC braking.
+
0
-

to (Enable during stop), and the RUN command (FW/
 
) and duration (

while the RUN command is still active. Refer to the
FW
F-SET
A052
F-OUT
Example 2: Analog change in F-SET

. DC braking continues until the set point exceeds
Section 3-5
Running Free run DC brake
A053

).
) can both be set. You can option-

), during which the motor will
 
to (Frequency detection). In
ON
DB DB
 
= with a step-
t
A055
DB

.
105