Nidec DFS Series Power Installation Manual

DFS1/DFS2 Power Installation Guide 43Issue Number: 2Safety information Product information Mechanical installation Electrical installation Technical data4.12 Output contactorA contactor is sometimes required to be installed between the drive and motor for safety purposes.The recommended motor contactor is the AC3 type.Switching of an output contactor should only occur when the output of the drive is disabled.Opening or closing of the contactor with the drive enabled will lead to:1. OI ac trips (which cannot be reset for 10 seconds)2. High levels of radio frequency noise emission3. Increased contactor wear and tearThe Drive Enable terminal (terminal 31 on Unidrive M700 / M701 and terminal 29 onPowerdrive 300) when opened provides a Safe Torque Off function. This can in many cases replaceoutput contactors.For further information see the Control User Guide.4.13 Safe Torque OffThe drives are provided with a Safe Torque Off function. In many cases this can replace outputcontactors.For further information see the Unidrive M700, M701, M702 Control User Guide. CT Part Number:0478-0353-02.4.14 BrakingOutput contactorIf the cable between the drive and the motor is to be interrupted by a contactor or circuitbreaker, ensure that the drive is disabled before the contactor or circuit breaker is openedor closed. Severe arcing may occur if this circuit is interrupted with the motor running athigh current and low speed.Safe Torque Off does not provide isolationThe Safe Torque Off function does not remove dangerous voltages from the drive anddoes not isolate the motor output terminals.BrakingThe current range of DFS drives are not provided with Braking resistors, cabling or a brakeoverload protection circuit that disconnects the drive from the supply in the event of anoverload or fault.Contact the supplier of the drive if braking is required.WARNINGWARNINGWARNING