Altivar 312 Variable Speed Drives Page 19 Introduction

19 Altivar 312 variable speed drives Functions Functions (continued) Automatic catching of a spinning load with speed detection ("catch on the fly") This function is used to restart the motor smoothly after one of the following events, provided the run command is still present: Loss of line supply or power off Detected fault reset or automatic restart Freewheel stop On disappearance of the event, the rms speed of the motor is detected in order to restart on a ramp from this speed and return to the reference speed. Speed detection can take up to 1 s depending on the initial deviation. This function is automatically disabled if the brake sequence is configured. It is suitable for machines for which the motor speed loss is negligible during the loss of line supply (such as machines with high inertia, fans and pumps driven by a residual flow, etc.). Automatic restart This function enables the drive to be restarted automatically after it has locked in detected fault mode, provided the detected fault has disappeared and the other operating conditions permit a restart. This restart is performed by a series of automatic attempts separated by increasingly longer waiting periods of 1 s, 5 s, 10 s, then 1 minute for subsequent periods. The restart procedure can last between 5 minutes and an unlimited time. If the drive has not restarted after the configured time, it will lock and the procedure is abandoned until it has been powered off and on again. The detected faults which permit this type of restart are: Line overvoltage Motor thermal overload Drive thermal overload DC bus overvoltage Loss of one input phase External detected fault Loss of 4-20 mA reference CANopen bus detected fault Modbus serial link detected fault Line voltage too low. For this detected fault, the function is always active, even if it is not configured. For these detected faults, the relay configured as a detected fault relay remains activated if the function is configured. The speed reference and direction of operation must be maintained for this function. This function is suitable for machines or installations which are in continuous operation or are not monitored, and where a restart will not endanger equipment or personnel in any way. Derated operation in the event of an undervoltage The line voltage monitoring threshold is lowered to 50% of the motor voltage. In this case, a line choke must be used and the performance of the drive cannot be guaranteed. Detected fault relay, unlocking The detected fault relay is energized when the drive is powered up and has not detected a fault. It contains an N/C contact and an N/O contact with common point. The drive is unlocked after a detected fault in one of the following ways: By powering down until the ON LED goes out, then switching the drive back on By assigning a logic input to the External detected faults function By the Automatic restart function, if it has been configured Resetting operating time to zero The drive operating time can be reset to zero.

Previous Page
Next Page