AuCom MVE Series User Manual page 30

Constant Current with Current Ramp
Current ramp soft starting raises the current from a specified starting level (1) to a maximum limit (3), over an
extended period of time (2).
Current ramp starting can be useful for applications where:
• the load can vary between starts (for example a conveyor which may start loaded or unloaded). Set the
initial current (parameter 2C) to a level that will start the motor with a light load, and the current limit
(parameter 2D) to a level that will start the motor with a heavy load.
the load breaks away easily, but starting time needs to be extended (for example a centrifugal pump
•
where pipeline pressure needs to build up slowly).
• the electricity supply is limited (for example a generator set), and a slower application of load will allow
greater time for the supply to respond.
4
700%
600%
500% 2
400%
300%
200%
1
100%
Constant Current with Kickstart
Kickstart provides a short boost of extra torque at the beginning of a start, and can be used in conjunction with
current ramp or constant current starting.
Kickstart can be useful to help start loads that require high breakaway torque but then accelerate easily (for example
helical rotor pumps).
6
2
1
4
3
Rotor speed (% full speed)
Timed Voltage Ramp
Timed voltage ramp (TVR) soft starting ramps the application of voltage to the motor over a defined time period. The
voltage ramp reduces the initial starting torque and slows the motor's rate of acceleration.
TVR starting can be useful for applications where multiple motors of different sizes are connected in parallel, and/or
the loads are not mechanically linked.
NOTE
TVR soft starting is not suitable for high inertia loads (such as fans), which require a high level of voltage to
accelerate the load.
NOTE
For multiple motors of the same sizes, and/or mechanically coupled loads, use constant current starting.
3
Time
5
Initial Current
1: (parameter 2C)
Start Ramp Time
2: (parameter 2B)
Current Limit
3: (parameter 2D)
4: Full voltage current
Kickstart Level
1: (parameter 2G)
Kickstart Time
2: (parameter 2F)
Initial Current
3: (parameter 2C)
4: Start Ramp Time (parameter 2B)
Current Limit
5: (parameter 2D)
6: Full voltage current
MVE User Manual (710-17074-00H) |
OPERATION
29