Siemens SINUMERIK 840C - Manual (Page 469)

7 Drive Machine Data (SIMODRIVE Drive MD) 12.93
7.2.2 FDD MD (data description - SW 3)
Limit current power section 1108
Default value Lower input limit Upper input limit Units
200 1 500 A
Active on
Power On
Input of maximum thermally permissible current of power section. The input is an RMS value.
This machine data is automatically parameterized for Siemens power sections by the machine
data "Power section code" (MD 1106).
Reduction factor max. motor current set-up mode 1110
Default value Lower input limit Upper input limit Units
1 0 100 %
Active on
Power On
Input of reduction factor for set-up mode. The transistor limit current (MD 1107) acts as the
reference value. Please note that if the current limit calculated for set-up mode exceeds the
maximum unit-specific current value, then it will be reduced to this value. The maximum
permissible unit-specific current is calculated as a minimum value from MD 1104 (maximum
motor current) x
2 x MD 1105 (reduction max. motor current), maximum current of power
section (e.g. 9/18A 100% corresponds to 18 A
RMS
) and MD 1108 (power section limit
current) x 2.
Example:
Max. motor current (MD 1104) = 5 A
Reduction max. motor current (MD 1105) = 100 %
Transistor limit current (MD 1107) = 25 A
Power section limit current (MD 1108) 18 A
Unit-specific max. permissible current (normal mode) = min. (100 % x 5 A; 25 A; 18 A x 2)
Unit-specific max. permissible current (normal mode) = 5 A
Example 1: Reduction factor max. motor current set-up mode (MD 1110) = 50 %
Unit-specific permissible current (set-up mode) = min. (5 A; 25 A x 0.5)
Unit-specific permissible current (set-up mode) = 5 A
Example 2: Reduction factor max. motor current set-up mode (MD 1110) = 10 %
Unit-specific permissible current (set-up mode) = min. (5 A; 25 A x 0.1)
Unit-specific permissible current (set-up mode) = 2.5 A
Number of pole pairs motor 1112
Default value Lower input limit Upper input limit Units
3 0 4 –
Active on
Power On
Input of number of pole pairs of motor as specified on the motor data sheet (non-Siemens
motor) or through automatic parameterization using machine data "Motor code number"
(MD 1102). The numbers of pole pairs encountered in practice are 2, 3 and 4. The pole pair
number 0 is entered when motor/power section combinations which have not been enabled are
loaded.
7–54 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)