GE Industrial Solutions ASTAT XT - Manual (Page 55)

55 • Starting Procedure
Continued from previous page
6.2 Examples of Starting Curves
6.2.1
Light Loads - Pumps, Etc.
(In these cases the actual current is always lower than the Current Limit setting)
Starting Voltage-
set to 30%
Current Limit
- set to 300-350%
Ramp UP Time
- set to 10 sec.
Upon start, the voltage quickly increases to the Starting Voltage value (30% of Un) and then gradually ramps-
up to nominal.
The current will simultaneously increase to peak current value (lower than the Current Limit setting), before
smoothly decreasing to the operating current.
6.2.2
High Inertia Loads: Crushers, Centrifuges, Mixers, Etc.
(In these cases the actual current is at the CURRENT LIMIT setting during part of the starting time)
Starting Voltage–
set 40%
Current Limit– set 400%
Ramp UP Time
– set 3 sec
• Check Last Start Time and set Max. Start time to approximately 5 seconds
longer than the Last Start Time.
• For future reference it is advised to keep records of the following parameters in the
Statistical Data:
Last Start Time:
Last Start Curr.:
Motor acceleration
time to full speed is
as required?
No
Yes
If acceleration time is too short, increase Ramp
UP Time
setting and/or decrease Current
Limit
setting (when decreasing Current
Limit
, make sure that the motor increases
speed gradually and does not stall).
A
Apply the START command