Danfoss VLT AQUA Drive FC 202 Operating Instructions Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

6.1.3. Submersible Pump ApplicationThe system consists of a submersible pump controlled by a Danfoss VLT AQUA Drive and a pressure transmitter. The transmitter gives a 4-20 mA feedbacksignal to the VLT AQUA Drive, which keeps a constant pressure by controlling the speed of the pump. To design a drive for a submersible pump application,there are a few important issues to take into consideration. Therefore the drive used must be chosen according to motor current.1. The motor is a so called “Can motor” with a stainless steel can between the rotor and stator. There is a larger and a more magnetic resistantair-gap than on a normal motor hence a weaker field which results in the motors being designed with a higher rated current than a norm motorwith similar rated power.2. The pump contains thrust bearings which will be damaged when running below minimum speed which normally will be 30 Hz.3. The motor reactance is nonlinear in submersible pump motors and therefore Automatic Motor Adaption (AMA) may not be possible. However,normally submersible pumps are operated with very long motor cables that might eliminate the nonlinear motor reactance and enable the driveto perform AMA. If AMA fails, the motor data can be set from parameter group 1-3* (see motor datasheet). Be aware that if AMA has succeededthe drive will compensate for voltage drop in the long motor cables, so if the Advanced motor data are set manually, the length of the motorcable must be taken into considerations to optimize system performance.4. It is important that the system is operated with a minimum of wear and tear of the pump and motor. A Danfoss Sine-Wave filter can lower themotor insulation stress and increase lifetime (check actual motor insulation and the frequency converter du/dt specification). It is recommendedto use a filter to reduce the need for service.5. EMC performance can be difficult to achieve due to the fact that the special pump cable which is able to withstand the wet conditions in the wellnormally is unscreened. A solution could be to use a screened cable above the well and fix the screen to the well pipe if it is made of steel (canalso be made of plastic). A Sine-Wave filter will also reduce the EMI from unscreened motor cables.The special “can motor” is used due to the wet installation conditions. The drive needs to be designed for the system according to output current to beable to run the motor at nominal power.To prevent damage to the thrust bearings of the pump, it is important to ramp the pump from stop to min. speed as quick as possible. Well-knownmanufacturers of submersible pumps recommend that the pump is ramped to min. speed (30 Hz) in max. 2 -3 seconds. The new VLT© AQUA Drive isdesigned with initial and final Ramp for these applications. The initial and final ramps are 2 individual ramps, where Initial Ramp, if enabled, will rampthe motor from stop to min. speed and automatically switch to normal ramp, when min. speed is reached. Final ramp will do the opposite from min. speedto stop in a stop situation.Pipe-Fill mode can be enabled to prevent water hammering. The Danfoss frequency converter is capable of filling vertical pipes using the PID controllerto slowly ramp up the pressure with a user specified rate (units/sec). If enabled the drive will, when it reaches min. speed after startup, enter pipe fillmode. The pressure will slowly be ramped up until it reaches a user specified Filled Set Point, where after the drive automatically disables Pipe Fill Modeand continues in normal closed loop operation.This feature is designed for irrigation applications.Electrical WiringTypical parameter settingsTypical/recommended settings in brackets().Parameters:Motor Rated Power Par. 1-20 / par. 1-21Motor Rated Voltage Par. 1-22Motor Current Par. 1-24Motor Rated Speed Par. 1-28Enable Reduced Automatic Motor Adaptation (AMA in par. 1-29)NB!Note the analog input 2, (terminal (54) format must beset to mA. (switch 202).6. Application ExamplesVLT® AQUA DriveOperating Instructions48 MG.20.M5.02 - VLT® is a registered Danfoss trademark6