104
Digistart D3: User Guide
Issue: G
10.6 Soft Braking
For applications with high inertia and/or a variable load, the Digistart D3 can be configured for soft braking.
In this application the Digistart D3 is employed with forward run and braking contactors. When the Digistart D3
receives a start signal (pushbutton S1), it closes the forward run contactor (K1) and controls the motor according to
the programmed primary motor settings.
When the Digistart D3 receives a stop signal (pushbutton S2), it opens the forward run contactor (K1) and closes the
braking contactor (K2) after a delay of approximately 2-3 seconds (K1T). K12 is also closed to activate the secondary
motor settings, which should be user programmed for the desired stopping performance characteristics.
When motor speed approaches zero, the zero speed sensor (A2) stops the soft starter and opens the braking
contactor (K2).
2
1
6
3
4
7
5
220-
440
VA
C
110-
210
VA
C
+10% -15%
+10% -15%
1
Control voltage
K12
Brake relay
2
Remote control inputs
K13
Zero speed sensor relay
3
Motor thermistor input
K1
Line contactor (Run)
4
RTD/PT100 input
K2
Line contactor (Brake)
5
Relay outputs
K1T
Run delay timer
6
Three-phase supply
K2T
Brake delay timer
7
Motor terminals
K3T
Zero speed sensor delay timer*
A2
Zero speed sensor
S1
Start contact
F1
Semiconductor fuses (optional)
S2
Stop contact
K10
Run relay
S3
Reset contact
K11
Start relay
* The K3T timer is only required if the zero speed sensor is the type that performs a self-test upon power-up and
momentarily closes the output relay.
Parameter settings:
•
Pr 3A
Input A Function
(terminals DI4, +24V)
•
Select 'Motor Set Select' - assigns Input A for Motor set selection.
•
Set starting performance characteristics using the primary motor set.
•
Set braking performance characteristics using the secondary motor settings.
•
Pr 4G
Relay C Action
•
Select 'Trip' - assigns Trip function to Relay Output C.
NOTE
If the Digistart D3 trips on supply frequency (Pr 16H
Frequency
) when the braking contactor K2 opens,
modify the frequency protection settings.
