Siemens SIRIUS 3RW51, Руководство по эксплуатации оборудования

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Parameters
Parameter Description
Starting voltage The starting voltage determines the starting torque of the motor. A lower starting
voltage results in a lower switch-on torque and a lower starting current. Set the
starting voltage to a value that ensures that the motor starts up immediately and
smoothly once the start command reaches the 3RW51 soft starter.
• Factory setting: 30%
• Setting range: 30 ... 100%
Ramp-up time The ramp-up time determines the time taken to increase the motor voltage from
the parameterized starting voltage to the line voltage. This has an influence on
the motor's acceleration torque which drives the load during the ramp-up oper‐
ation. A longer ramp-up time results in a shorter acceleration torque across the
motor ramp-up. The motor therefore runs up more slowly and smoothly.
Set the length of the ramp-up time such that the motor can reach its rated speed
by the time the end of the ramp is reached. The actual motor starting time is load-
dependent and can differ from the parameterized ramp-up time.
If you choose a time that is too short, the ramp-up time ends before the motor has
accelerated to speed. If the time selected is too short, a very high starting current
that equals the direct starting current at the same speed will occur. In this case,
the 3RW51 soft starter can switch itself off via the internal overload protection
function and signal fault.
With the setting "0 s", the motor is switched on with a ramp-up time of 100 ms
approximately.
• Factory setting: 10 s
• Setting range: 0 ... 20 s
8.2 Current limiting function
Operating principle
Activate the current limiting function if you want to ensure that a specific current value is not
exceeded during motor starting.
The motor is always started up with the voltage ramp. If the current exceeds the parameterized
current limit x I
e
, the voltage ramp function is aborted and the current limitation function starts.
The current limitation function remains active until the 3RW51 soft starter has detected the
motor ramp up and the motor is in a normal operating state.
Application
• Avoiding current surges
• Reducing energy costs
Functions
8.2 Current limiting function
SIRIUS 3RW51 Soft Starter
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Equipment Manual, 09/2020, A5E37108631002A/RS-AC/003