Program features 63 DC magnetizationDC magnetization can be applied to the motor to• heat the motor to remove or prevent condensation, or• to lock the rotor at, or near, zero speed.Pre-heatingA motor pre-heating function is available to prevent condensation in a stopped motor,or to remove condensation from the motor before start. Pre-heating involves feedinga DC current into the motor to heat up the windings.Pre-heating is deactivated at start, or when one of the other DC magnetizationfunctions is activated. With the drive stopped, pre-heating is disabled by the safetorque off function, a drive fault state, or the process PID sleep function. Pre-heatingcan only start after one minute has elapsed from stopping the drive.A digital source to control pre-heating is selected by parameter 21.14 Pre-heatinginput source. The heating current is set by 21.16 Pre-heating current.Pre-magnetizationPre-magnetization refers to DC magnetization of the motor before start. Dependingon the selected start mode (21.01 Start mode or 21.19 Scalar start mode), pre-magnetization can be applied to guarantee the highest possible breakaway torque,up to 200% of the nominal torque of the motor. By adjusting the pre-magnetizationtime (21.02 Magnetization time), it is possible to synchronize the motor start and, forexample, the release of a mechanical brake.DC holdThe function makes it possible to lock the rotor at (near) zero speed in the middle ofnormal operation. DC hold is activated by parameter 21.08 DC current control. Whenboth the reference and motor speed drop below a certain level (parameter 21.09 DChold speed), the drive will stop generating sinusoidal current and start to inject DCinto the motor. The current is set by parameter 21.10 DC current reference. When thereference exceeds parameter 21.09 DC hold speed, normal drive operationcontinues.ghv Vertriebs-GmbH | Am Schammacher Feld 47 | 85567 Grafing | Telefon + 49 80 92 81 89 0 | info@ghv.de | www.ghv.de
