AuCom MVE series User Manual page 79

APPENDIX
Using the MVE to Control a Slip-Ring Motor
The MVE can be used to control a slip-ring motor, using rotor resistance.
1
2
V1
V2
3
P1
1 Sub-states
t1 Main contactor close time
t2 Rotor resistance contactor close time
t3 Bypass contactor close time
2 Output voltage
V1 100% voltage
V2 Slip-ring retard voltage
Commissioning
•
1. Configure the MVE as follows:
Parameter settings:
• Parameter 7A
Select 'Changeover Contactor'
•
Parameter 7B
•
Set this to the maximum time (5m:00s).
•
Parameter 12A
•
• Select 'Dual Ramp' (for slip-ring induction motor control)
• Parameter 12C
• Default setting is 150 milliseconds. Set this to a value just greater than the changeover contactor (K3) pole
closing time.
• Parameter 12D
Default setting is 50%. Set this parameter to a value which is high enough to cause the motor to instantly
•
accelerate once the rotor resistance (R1) has been bridged out and low enough to avoid a motor current pulse.
2. Start the motor under normal load conditions and record the time it takes to reach a constant speed with external rotor
resistance (R1) in the circuit. Stop the motor soon after a constant speed has been reached. Change parameter 7B to the
recorded time value.
3. Start the motor under normal load conditions and monitor the motor speed behaviour and motor current when the
changeover contactor (K3) switches in to short-out the rotor resistance (R1)
If the motor does not start to accelerate immediately after changeover, increase the setting of parameter 12D.
If there is a pulse in motor current immediately after changeover, reduce the setting of parameter 12D.
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| MVE User Manual (710-17074-00G)
t1
S2
P2
Relay A Function
Relay A On Delay
Motor Data-1 Ramp
Changeover Time
Slip Ring Retard
t2
S3
P3
3 States
S1 Ready
S2 Pre-start tests
S3 Starting
S4 Running
4 Phases of operation
P1 Start command
P2 Rotor resistance current ramp
P3 Shorted rotor current ramp
t3
S4