DMC SuperSigma2 User Manual

SuperSigma2 AM PMS – V1.5.6 17-1-2020 Page 77 (97) ©2019 DMC GmbH Herten Germany
Example
• Nominal rated current 90 A
• Insulation class F
• Rise time 50 s
Thus, the motor heats up 105 °C in 50 s when 180 A is drawn, the providing starting temperature is 40 °C.
Parameters
The controller will have a set of parameters with which the I
2
t feature can be set up:
• Nominal rated current of the motor.
• The temperature rise time.
• Percentage of the maximum drive current 1.
• Percentage of the maximum drive current 2.
• Percentage of the maximum drive current 3.
The location, unit, range and step size of these adjustments can be found in the “Menu 7 “Limits Setup””.
This rise time must be established by trial and error. Once this time is established, it sets a time in which the surplus of
the nominal current may flow through the motor. After that time, the I
2
t function will limit the motor current in three
steps.
There is Microsoft Excel sheet (available on request) which can be used to setup the I
2
t parameters in the “Menu 7 “Limits
Setup”” of the Sigma2 controller. In this sheet various current settings and the time can be filled in the white boxes (see
also the example below). The figures in bold in the dark green box are the actual current limit value in percentages. These
need to be configured in the “Menu 7 “Limits Setup”” of the controller.
A limit will run from 100 % (no cut back) to 0 % (full cut back). This is displayed also in the “Status Menu” at “Drive torque
limit”.
When the I
2
t feature is actually limiting the current, the “Status menu” will show ‘T1’, ‘T2’ or ‘T3’ limit indication,
depending in which phase the I
2
t function currently is.
The reason that percentages are used instead of real currents, is that all other limit features such as low voltage limit and controller temperature
limit are also in percentages.
Note that the maximum current is specified by the maximum RMS current in the Motor Autotune menu (“Menu 4 “PMS
Motor Auto Tuning”).
Example
An example of the MS Excel sheet is given below.
According to the sheet, 400 Arms is allowed to flow through the motor for a maximum time of 20 s. After that the I
2
t will
cut back the current to the first step (63 %, 250 Arms).
Motor Setup Menu Maximum Torque current in drive ImotMax 400 Arms
Nominal motor current NomCurr 100 Arms 100 Arms
I
2
t Time I2TTime 180 sec 180 sec
I
2
t Cut Back Current 1 I2TCutB1 250 Arms 63% %
I
2
t Cut Back Current 2 I2TCutB2 160 Arms 40% %
I
2
t Cut Back Current 3
I2TCutB3 120 Arms 30% %
I
2
x t
1800000 A^2s
Step 0 T1 T2 T3
I_max [A] 400 250 160 120
I_offset [A] 300 150 60 20
t [s] 20,00 80,00 500,00 4500,00
t [min] 0,33 1,33 8,33 75,00
t [h] 0,01 0,02 0,14 1,25
Menu Motor Limits
Setting up I2t parameters
To use in Motor Limits Menu

DMC SuperSigma2 Specifications

General

Brand	DMC
Model	SuperSigma2
Category	Engine
Language	English