27
6.3Load inductance
The total load inductance must be sufficient to keep the current ripple within the 50% limit
ripple (Ir) can be calculated by using the following equation:
0.5 x Vs |
|
Ir = | (A) |
f x L |
|
L - load inductance in mH.
Vs - Voltage of the DC supply in Volts. f - Switching frequency in KHz.
If motor inductance does not exceed this value, a choke should be added (on the motor branch) summing together the required inductance
Lch = L - Larm
Lch - Choke inductance
Larm - Armature inductance
6.4AC power supply
AC power supply can be at any voltage in the range defined within the technical specifications (chapter 3). However, if the power source to the power supply is the AC line (through a transformer), safety margins have to be considered to avoid activating the under/over voltage protection due to line variations and/or voltage drop under load.
The nominal DC bus voltage should be in the following range:
1.2Vdcmin < Vdc < 0.9Vdcmax
Vdcmin - Minimum DC bus in the table of chapter 3
Vdcmax - Maximum DC bus in the table of chapter 3
ISP - Rev 6/95