Danfoss iC2 - Page 170

Selection number Selection name Selection description
3 Pre-magnetizing Builds up a magnetic field while the motor is stopped. This allows
the motor to produce torque quickly at commands (induction
motors only). This premagnetizing function does not help the 1st
start command.
Two different solutions are available to pre-magnetize the
machine for the 1st start command:
Solution 1:
• 1. Start the frequency converter with a 0 RPM reference.
• 2. Wait 2–4 rotor time constants (see the formula below)
before increasing the speed reference.
Solution 2:
• 1. Set P 5.6.1 Start Zero Speed Time to the premagnetize time
(2–4 rotor time constants).
• 2. Set P 5.6.2 Start Function to [0] DC hold.
• 3. Set the DC hold current magnitude (P 5.7.6 DC Hold Current
% to be equal to Ipre-mag = Unom/(1.73 x Xh).
Sample rotor time constants = (Xh+X2)/(6.3*Freq_nom*Rr) 1 kW
= 0.2 s 10 kW = 0.5 s 100 kW = 1.7 s).
10 Coast With Stop at Low Reference When a stop command is given, or a start command is removed,
and the reference is below P 5.7.2 Min Speed for Function at Stop
[Hz], the motor is disconnected from the drive.
11 DC Hold With Stop at Low Reference When a stop command is given, or a start command is removed,
and the reference is below P 5.7.2 Min Speed for Function at Stop
[Hz], energizes the motor with a DC-hold current (see P 5.7.6 DC
Hold Current %).
P 5.7.2 Min Speed for Function at Stop [Hz]
Use this parameter to set the output frequency at which to activate P 5.7.1 Function at Stop.
Default value: 0.0 Parameter type: Range (Size Related)
Parameter
number:
182 Unit: Hz
Data type: uint16 Access type: Read/Write
P 5.7.3 DC Brake Time
Set the duration of the DC brake current set in P 5.7.4 DC Brake Current %, once activated.
Default value: 10.0 Parameter type: Range (0.0–60.0)
Parameter
number:
202 Unit: s
Data type: uint16 Access type: Read/Write
170 | Danfoss A/S © 2024.03 AB413939445838en-000301 / 130R1254
Application Guide | iC2-Micro Frequency Converters