Synchronous Motors In Field Weakening Range - HEIDENHAIN iTNC 530 Technical Manual

6.8.9 Synchronous Motors in Field Weakening Range

February 2002
Synchronous motors can also be operated with a weakened field. This is
necessary, for example, for high-speed synchronous spindle motors, since the
inverter voltage is not sufficient at high speeds.
If the power supply fails, the dc-link voltage increases sharply. As a result, the
inverters and possibly the motor might be damaged. To protect the inverters
and the motor from being damaged, you can use a braking resistor such as PW
210 for non-regenerative inverter systems and a braking-resistor module such
as UP 110 or a voltage-protection module for regenerative inverter systems.
For synchronous motors, the operation with a weakened field is automatically
activated if MP2160 = 1 has been entered. You do not need to make any
further settings.
7 If you are using a synchronous motor with an appropriate module to protect
the system in the event of a power supply failure, enter MP2160 = 1 so that
the synchronous motor can be operated with a weakened field.
7 If you are using a synchronous motor without an appropriate module to
protect the system in the event of a power supply failure, enter MP2160 =
0 so that the synchronous motor cannot be operated with a weakened field.
MP2160 Protection against failure of power supply for synchronous
motor in field-weakening range
Input: 0: Do not protect
1: Protect
The Control Loop 6 – 155